WO2010080823A1 - Frequency drift estimation for low cost outdoor unit - Google Patents

Frequency drift estimation for low cost outdoor unit Download PDF

Info

Publication number
WO2010080823A1
WO2010080823A1 PCT/US2010/020246 US2010020246W WO2010080823A1 WO 2010080823 A1 WO2010080823 A1 WO 2010080823A1 US 2010020246 W US2010020246 W US 2010020246W WO 2010080823 A1 WO2010080823 A1 WO 2010080823A1
Authority
WO
WIPO (PCT)
Prior art keywords
signals
frequency
dsp
oscillator
intermediate frequency
Prior art date
Application number
PCT/US2010/020246
Other languages
French (fr)
Inventor
Robert F. Popoli
Original Assignee
The Directv Group, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by The Directv Group, Inc. filed Critical The Directv Group, Inc.
Priority to MX2011007027A priority Critical patent/MX2011007027A/en
Priority to BRPI1006912A priority patent/BRPI1006912A2/en
Publication of WO2010080823A1 publication Critical patent/WO2010080823A1/en

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04HBROADCAST COMMUNICATION
    • H04H40/00Arrangements specially adapted for receiving broadcast information
    • H04H40/18Arrangements characterised by circuits or components specially adapted for receiving
    • H04H40/27Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95
    • H04H40/90Arrangements characterised by circuits or components specially adapted for receiving specially adapted for broadcast systems covered by groups H04H20/53 - H04H20/95 specially adapted for satellite broadcast receiving
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03JTUNING RESONANT CIRCUITS; SELECTING RESONANT CIRCUITS
    • H03J7/00Automatic frequency control; Automatic scanning over a band of frequencies
    • H03J7/02Automatic frequency control
    • H03J7/04Automatic frequency control where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant

Definitions

  • the present invention relates generally to satellite video systems, and in particular, to a method, apparatus, and article of manufacture for frequency drift estimation in satellite outdoor unit systems.
  • Satellite broadcasting of communications signals has become commonplace. Satellite distribution of commercial signals for use in television programming currently utilizes multiple feedhorns on a single Outdoor Unit (ODU) which supply signals to up to eight Integrated Receiver/Decoders (IRDs), e.g., set top boxes, on separate cables from a multiswitch.
  • ODU Outdoor Unit
  • IRDs Integrated Receiver/Decoders
  • FIG. 1 illustrates a typical satellite-based broadcast system of the related art.
  • System 100 uses signals sent from Satellite A (SatA) 102, Satellite B (SatB) 104, and Satellite C (SatC) 106 that are directly broadcast to an Outdoor Unit (ODU) 108 that is typically attached to the outside of a house 110.
  • ODU 108 receives these signals and sends the received signals to IRD 112, which decodes the signals and separates the signals into viewer channels, which are then passed to monitor 114 for viewing by a user.
  • IRD 112 which decodes the signals and separates the signals into viewer channels, which are then passed to monitor 114 for viewing by a user.
  • the orbital slots are typically designated by their longitude, so, for example, a satellite 102 located in the orbital slot at 101 degrees West Longitude (WL) is usually referred to as transmitting from "101.”
  • Satellite uplink signals 116 are transmitted by one or more uplink facilities 118 to the satellites 102-106 that are typically in geosynchronous orbit. Satellites 102-106 amplify and rebroadcast the uplink signals 116, through transponders located on the satellite, as downlink signals 120. Depending on the satellite 102-106 antenna pattern, the downlink signals 120 are directed towards geographic areas for reception by the ODU 108.
  • Each satellite 102-106 broadcasts downlink signals 120 in typically thirty-two (32) different frequencies, which are licensed to various users for broadcasting of programming, which can be audio, video, or data signals, or any combination.
  • These signals are typically located in the Ku-band of frequencies, i.e., 11-18 GHz, but can also be broadcast in the Ka-band of frequencies, i.e., 18-40 GHz, but typically 20-30 GHz.
  • the downlink signals 120 are downconverted to lower frequencies using an oscillator and a mixer.
  • the oscillator is a Dielectric Resonant Oscillator (DRO). If the DRO frequency drifts, the downconversion of the downlink signals 120 drifts as well, which makes processing of such downconverted signals more difficult. Further, as satellites 102-106 broadcast additional services and additional channels to viewers, as well as additional satellite signals present in such bandwidths, it will be more efficient to monitor and, if necessary, correct drifts in the DRO frequency.
  • DRO Dielectric Resonant Oscillator
  • a receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (A/D) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.
  • DSP Digital Signal Processor
  • Such a system further optionally comprises the drift estimator driving a digital mixer within the DSP to compensate for the determined frequency drift, an output of the drift estimator being fed back to the oscillator to control the frequency drift of the oscillator, an automatic gain control coupled between the mixer and the A/D converter, the A/D converter sampling the signals at the intermediate frequency at a speed greater than 1 gigasample per second, the satellite signals being transmitted in at least the Ku-band of frequencies, the satellite signals being further transmitted in at least the Ka-band of frequencies, a Digital-to Analog Converter (DAC), coupled to the DSP, and an output of the DAC being mixed with a second oscillator, such that an output of the receiver antenna system is set to a desired band on a single wire interface.
  • DAC Digital-to Analog Converter
  • a system for distributing a plurality of satellite signals on a single interface in accordance with one or more embodiments of the present invention comprises an oscillator for down- converting the plurality of satellite signals to signals at an intermediate frequency, an Automatic Gain Controller (AGC) for gain controlling the signals at the intermediate frequency, an analog- to-digital (AJO) converter, coupled to the AGC, for receiving the signals at the intermediate frequency, wherein the A/D converter directly samples the signals at the intermediate frequency, and a Digital Signal Processor (DSP), coupled to the A/D converter, wherein a first output of the DSP is used to determine the intermediate frequency and a second output of the DSP is an input to the single interface.
  • AGC Automatic Gain Controller
  • AJO analog- to-digital converter
  • Such a system further optionally comprises a Digital-to- Analog Converter (DAC), coupled to the second output of the DSP, the first output of the DSP determining the intermediate frequency by controlling a frequency of the oscillator, the first output of the DSP driving a compensatory frequency shift by controlling a digital mixer internal to the DSP, the oscillator being a Dielectric Resonance Oscillator (DRO), the plurality of satellite signals being transmitted in a plurality of frequency bands, the plurality of frequency bands comprising a Ka-band and a Ku-band, the DRO down-converting the Ka-band to at least a first intermediate frequency band and the DRO down-converting the Ku-band to a second intermediate frequency band as convenient for A/D conversion, the A/D converter sampling the signals at the intermediate frequency at a rate greater than the Nyquist rate for the signals at the intermediate frequency, state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, and the diagnostic output comprising at least
  • FIG. 1 illustrates a typical satellite-based broadcast system of the related art
  • FIG. 2 illustrates a typical Single Wire Multiswitch (SWM) of the related art
  • FIGS. 3A and 3B illustrate related LNB modules and an LNB module in accordance with one or more embodiments of the present invention, respectively;
  • FIG. 4 illustrates an Analog-to-Digital subsystem functionality in accordance with one or more embodiments of the present invention
  • FIG. 5 illustrates a block diagram of the Digital Single Wire Multiswitch (DSWM) Channelizer in accordance with one or more embodiments of the present invention
  • FIG. 6 illustrates a coarse granularity channelizer in accordance with one or more embodiments of the present invention
  • FIG. 7 illustrates an exemplary fine granularity channelizer embodiment in accordance with one or more embodiments of the present invention.
  • FIG. 8 illustrates a block diagram of a frequency drift control system in accordance with one or more embodiments of the present invention.
  • one or more embodiments of the present invention provide significant commercial advantages over current analog designs. Further, simple brute force digital mimicry of known analog building blocks for demuxing/muxing/conversion processes are expected to lead to less commercially-viable designs.
  • DSP Digital Signal Processing
  • the present invention allows for better overall performance of an embodiment of a Single Wire Multiswitch (SWM) architecture because the present invention allows for the distribution of more channels within the same bandwidth (i.e., single wire bandwidth) through tighter packing of channels. Distribution of additional channels allows for the support of additional IRDs, or the same number of IRDs with less wired bandwidth. Further, embodiments of the present invention allow for inexpensive provision of baseband I/Q signals for reduced cost integration of a significant portion of the current IRD. Further still, embodiments of the present invention allow for the ability to provide greater flexibility for future system designs, and the potential of a smaller footprint for the SWM into the current system.
  • SWM Single Wire Multiswitch
  • Embodiments of the present invention also allow for simpler integration and interfaces between the parts of the present system, by simplifying the interface of shared demodulation resources without expending any bandwidth. This simplification allows for future products, such as Home Gateway and Multi-Dwelling Unit (MDU) architectures, to become possible.
  • MDU Multi-Dwelling Unit
  • FIG. 2 illustrates a typical Analog Single Wire Multiswitch. Hardware advances have increased A/D sampling rates in excess of 1 Gigasample/second
  • FIG. 2 illustrates SWM 200, where SWM 200 is fed by four composite signals 202-208, specifically LNBl 202, LNB2 204, LNB3 206, and LNB4 208, which are produced by the LNB module 300 hardware shown in FIG. 3A.
  • Each LNB signal 202-208 comprises multiple (e.g., three) stacked 500 MHz bandwidth signals, generated from downlink signals 120 and received at various orbital slots.
  • Ku-band signals 302 are from satellites at the 119 WL slot
  • Ku-band signals 304 are from satellites at the 110 WL slot
  • Ka-band signals 306 are from satellites at the 102.8 (also referred to as 103) WL slot
  • Ku-band signals 308 are from satellites at the 101 WL slot
  • Ka-band signals 302 are from satellites at the 99.2 (also referred to as 99) WL slot. Combinations of these signals, based on their polarization and transmission frequencies, are used to generate LNB signals 202-208.
  • the Ku-band signals 302, 304, and 308 are down-converted to an Intermediate Frequency (IF) band, 500 MHz wide, in the frequency range of 950-1450 MHz.
  • IF Intermediate Frequency
  • the Ka-band signals 306 and 310 are down-converted into two different 500 MHz wide bandwidths, namely the 250-750 MHz bandwidth (known as Ka-LO IF band or Ka-B IF band) and the 1650-2150 MHz bandwidth (known as Ka-HI IF band or Ka-A IF band), and are combined in various combinations to form signals 202-208
  • the SWM 200 shown in FIG. 2 selects any nine 40 MHz pieces of spectrum from LNBl 202 through LNB4 208 and stacks them to form a single composite signal called the channel stacked output 210.
  • the nine 40MHz channels are typically located on 102 MHz centers and range from 974 MHz to 1790 MHz (i.e., the channels are at 974, 1076, 1178, 1280, 1382, 1484, 1586, 1688, and 1790 MHz, respectively).
  • FIG. 3B illustrates an embodiment an LNB structure corresponding to a Digital SWM Design in accordance with the present invention.
  • the SWM module 300 is modified into module 312, where signals 302-310 are combined into different signals that are to be used as inputs to a modified SWM. Rather than stacking 1500 MHz into a single signal, as is done with signals 202-208, a larger number of outputs 312-326 are used. Although eight outputs 312-326 are shown, a larger or smaller number of outputs 312- 326 are possible without departing from the scope of the present invention.
  • LNBl signal 312, LNB2 signal 314, LNB5 signal 320, and LNB6 signal 322 each comprise two 500 MHz signals, each 500 MHz signal corresponding to a Ka-LO band signal and a Ka-HI band signal.
  • This arrangement is appropriate if the A/D has enough front end bandwidth to subsample the Ka-Hi band in its 2 nd Nyquist Band.
  • separate independent IF conversion for the Ka-Lo and Ka-Hi can be provided for more traditional 1 st Nyquist band sampling of each signal.
  • LNB3 signal 316, LNB4 signal 318, LNB7 signal 324, and LNB8 signal 326 are 500 MHz signals, each corresponding to a Ku-band signal.
  • the local oscillators 328 can be modified so that each of the signals 312-326 can have a desired and, possibly, different tunable starting frequency from 10 to 100 MHz, or beyond these limits if desired. Additional mixing can be added to achieve an offset frequency start for one or more of the signals 312-326 if desired. It is also possible within the scope of the present invention to implement tuning for signals 312-326 within the digital domain if desired.
  • FIG. 4 illustrates an embodiment of the Analog-to-Digital subsystem functionality of the present invention.
  • FIG. 4 shows the A/D subsystem 400 functions, where the sampling frequency Fs is adjustable, typically from 1.02 GHz to 1.2 GHz, but other frequencies and ranges are possible within the scope of the present invention.
  • Each signal 312-326 is placed through a filter 402, and then into an A/D converter 404, which produce the output signals 406-428.
  • the typical maximal sampling rate of the A/D converters 404, FsMAX is typically 1.35GHz, but other rates are possible without departing from the scope of the present invention.
  • the Ka HI signals are typically sub-sampled, so the analog paths should have a useable bandwidth of FsMAX + 500 MHz, which is typically 1.85 GHz. Alternatively if separate IF conversion is provided for the Ka-Hi signal then traditional 1 st Nyquist band sampling and Lo-Pass anti-alias filters would be employed.
  • FIG. 5 illustrates a block diagram of the DSWM Channelizer in accordance with one or more embodiments of the present invention.
  • Each input "x" 500, 502, etc. receives one of the A/D converter 404 outputs 406-428, and there can be extra inputs x 500, 502, etc., to allow for expansion of the system.
  • Each typical input x 500 is typically channelized into uniformly spaced K filters 504.
  • L the number of filter bands on the output side, is set to be equal to the number of stacked carriers desired at the stacked output 210.
  • FIG. 6 illustrates a coarse granularity channelizer in accordance with one or more embodiments of the present invention.
  • system 600 shows inputs 406-428, each entering a Real to Complex Hubert transformer 600.
  • Other types of Real to Complex transforms of the signal inputs 406-428 are also possible within the scope of the present invention.
  • the K filters 604 for each of the inputs 406-428 are set to 16, but other settings are possible within the scope of the present invention, including different values for K and x for each input 406-428. If the transponder count and spacing are uniform and well known, then K can be set to the number of transponders, etc. If, however, the number of transponders varies from satellite to satellite and/or the spacing of these transponders is not uniform, then a number of filters 604 greater than the maximum number of transponders to be encountered is typically used to allow for expansion.
  • the filters are then expanded or contracted by slight adjustments in the sampling frequency and by slight shifts in the down-converter LO frequency used in the LNB.
  • the down-converter LO frequency used in the LNB.
  • any channel spacings can be accommodated in any of the LNB outputs.
  • the signals 406-428, after being filtered by filters 602 are subjected to Fast Fourier
  • FFT Transforms
  • multiplexer 608 The combined signal is further processed to generate stacked output 210.
  • the present invention can use a non-maximally decimated filter bank of overlapping filters. This approach, along with the added technique of near-perfect reconstruction techniques simplify the fine granularity design.
  • the choice of the power of 2 composite K and L is chosen to simplify the FFT hardware implementation.
  • Other approaches or arrangements may also be used within the scope of the present invention.
  • FIG. 7 illustrates a fine granularity channelizer implementation in accordance with one or more embodiments of the present invention.
  • a fine granularity design using perfect or near perfect reconstruction polyphase filtering techniques has advantages over the coarse granularity approach.
  • the spectrum of each of the incoming 500 MHz blocks is subdivided much more finely than in the coarse granularity design.
  • the goal is to create a number of filters greater than or equal to the maximum number of expected transponders
  • the fine granularity design the goal is to divide up the spectrum into smaller pieces. This can be done in such a way that the fine pieces of spectrum can be "glued" back together to yield a nearly perfect reconstruction of any arbitrary spectral bandwidth within the granularity specified for the design. Employment of non-maximal decimation techniques can be used to simplify filter design if desired.
  • An illustrative design for a fine granularity system is shown in FIG. 7.
  • the system 700 shown in FIG. 7 has four output signals 702, 704, 706, and 708.
  • Outputs 702 and 704 are typically used to create two 500 MHz blocks of single wire bandwidth. Outputs 702 and 704 can then be power combined onto a single wire interface and thus replicate the output of related SWM designs, except that they provide more channels within the same physical bandwidth.
  • outputs 706 and 708 depicts two illustrative embodiments that include shared demod assets that do not expend any of the Single Wire Bandwidth. Other embodiments are possible within the scope of the present invention. Optionally, only one output 706 or 708 can be implemented, or other embodiments can be implemented alone or in any combination, without departing from the scope of the present invention.
  • Output 706 illustrates an approach having an additional internal single wire interface which drives conventional receiver/demod inputs.
  • Output 708 illustrates an approach where the receiver portion of the receiver demod chips can be eliminated at the same time as the last up-conversion of the processed signals. These chips correspond to I/Q near baseband demodulation. Other configurations are possible if some of the output polyphase filtering is incorporated directly on the demod chip for individual true baseband I/Q processing.
  • the output of the shared demod resources is Satellite Communicator Identification Code (SCID) filtered data which is networked onto any suitable physical layer and/or network layer protocols for distribution throughout the house or Multiple Dwelling Unit (MDU).
  • SCID Satellite Communicator Identification Code
  • MDU Multiple Dwelling Unit
  • the outputs 706 and 708 are Internet Protocol (IP) type outputs, or similar, that can be output over ethernet cabling, local area networks, RF, or other similar interfaces as desired, without departing from the scope of the present invention.
  • IP Internet Protocol
  • FIG. 8 illustrates a functional block diagram of processing of one 500MHz band in accordance with one or more embodiments of the present invention.
  • DSP Digital Signal Processing
  • signals 120 are received at ODU 108, and then are passed on to receiver 112.
  • an antenna 800 receives the signals 120 at both Ku-band and Ka-band (e.g., approximately 20 GHz), which are mixed at mixer 802 with the output of DRO 804.
  • This mixing process results in an output of mixer 802 of the sum and difference frequencies of signals 120 and DRO 804, and the frequency of DRO 804 is chosen to down-convert signals 120 to a frequency convenient for A/D conversion.
  • These signals are then typically filtered through a Band Pass Filter (BPF) 808 to remove harmonics and other unwanted signals, and then typically passed to Automatic Gain Control (AGC) 810 circuitry to normalize the signals 806 to a common signal strength.
  • BPF Band Pass Filter
  • AGC Automatic Gain Control
  • A/D 812 is a high-speed A/D converter, in that it can run at 1 Gigasample per second
  • GSPS Digital Signal Processor
  • DAC Digital Converter
  • Such signals are then mixed at mixer 818 with a local oscillator 820 and forwarded on to receiver 112.
  • this last mixer can be avoided if a DAC with sufficient BW is employed such that it can directly cover the desired single wire interface band.
  • the signals can be sent to a drift estimator 822, where drift of the frequency of signals 806 can be sensed.
  • Sensing drifts from various sources are achievable within the scope of the present invention, e.g., drifts which affect single carriers within a given bandwidth of signals or drifts which affect an aggregate of carriers, etc., however, the primary cause of drift of signals 806 is the DRO 804 frequency drift with temperature and age.
  • DRO 804 is located at the dish antenna 800 of ODU 108, and as the sun heats the dish antenna 800, DRO 804 warms up which causes drift, and as the sun goes down dish antenna 800 cools down, cooling down DRO 804, again causing drift in frequency.
  • the drift estimator 822 can be of several varieties.
  • One solution that can be used for drift estimator 822 is to create a discriminator based on a matched filter design, such that the expected type and distribution of transponders within the aggregate bandwidth of signals 806 is sensed.
  • Such a discriminator can be developed for individual transponders if desired, or the edges of the bandwidth can be sensed.
  • the discriminator can be a matched filter with a sign reversal about the center frequency, however, if the purpose is to drive the average drift of the DRO 804 to zero, a matched filter for all of the transponders within the aggregate bandwidth can be utilized.
  • the drift estimator algorithm may result in a biased estimate of each transponder's frequency that is down-converted by the DRO 804, the DRO 804 is tuned by the aggregate of the transponder drift discriminants (biased or not) and will therefore tend to average out the biasing effects due to any individual transponder gain slopes and ripples.
  • the present invention also allows for system 100, via ODU 108 (also called a Single- Wire Multiswitch ODU or SWM-ODU) to recognize large frequency deviations and frequency trends over the life of ODU 108.
  • ODU 108 also called a Single- Wire Multiswitch ODU or SWM-ODU
  • the present invention can provide not only feedback to DRO 804, but to system providers via receiver 112 callbacks or other communications between receiver 112 and system providers.
  • Receivers 112 typically comprise a high-speed internet or other interface to allow communications between the system provider and individual receivers 112; reporting system 100 health issues can now, through the use of the present invention, be undertaken by processors in receiver 112 and/or DSP 814.
  • drift estimator 822 The outputs of drift estimator 822 are then converted to analog voltages in DAC 824, and then fed back to DRO 804 via a control input 826 to DRO 804.
  • DRO 804 acts like a Voltage Controlled Oscillator (VCO) at this point, where the voltage applied at 826 controls the frequency output of DRO 804.
  • VCO Voltage Controlled Oscillator
  • a mixed signal ASIC will typically include the AGCs 810, ADCs 812, DSP 814, DACs 816, and a general purpose processor implementing the Drift Estimator 822 matched filter discriminant.
  • the general purpose processor has access to information regarding the state of each of these subsystems.
  • the matched filter results coupled with knowledge of the AGC states provides important diagnostic information if no match is found over the possible range of drift frequencies of a given expected transponder.
  • the system can thereby recognize the absence of expected transponders and can report this fault.
  • This fault represents a fault in system 100 to deliver the missing transponder to the ODU 108.
  • the failure of the match filter to find a match for any transponder in a given 500MHz band indicates the potential failure of one of the 500MHz signal paths 312,314,318,320, 322,324, and 326 or subsequent processing these signal paths indicating a potential hardware failure in the ODU 108.
  • ODU 108 mis-pointing is indicated.
  • the diagnostics described also have value. Analyzing a combination of matched filter and AGC results, information to aid in the initial ODU antenna pointing and verification of the final installation can be provided.
  • the above examples e.g., the use of state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, where the diagnostic output comprises at least one of fault recognition, fault reporting, performance monitoring, installation aiding, and installation verification for the system 100, are provided as examples of the class of diagnostics and installation verification aids possible by analysis of data related to the state of the subsystems of the given architecture. Any such diagnostics or installation aids derived from such state information is within the scope of this invention.
  • DRO 804 Although discussed with respect to voltage control of DRO 804, other methods of control of signals 806, and the effects of DRO 804 drift, can be accomplished with the present invention.
  • a digital compensation within DSP 814 of the frequency offset, once estimated by drift estimator 822, can also be achieved via feedback between drift estimator 822 and DSP 814.
  • a receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (AJO) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.
  • AJO analog-to-digital
  • DSP Digital Signal Processor
  • Such a system further optionally comprises the drift estimator driving a digital mixer within the DSP to compensate for the determined frequency drift, an output of the drift estimator being fed back to the oscillator to control the frequency drift of the oscillator, an automatic gain control coupled between the mixer and the A/D converter, the A/D converter sampling the signals at the intermediate frequency at a speed greater than 1 gigasample per second, the satellite signals being transmitted in at least the Ku-band of frequencies, the satellite signals being further transmitted in at least the Ka-band of frequencies, a Digital-to Analog Converter (DAC), coupled to the DSP, and an output of the DAC being mixed with a second oscillator, such that an output of the receiver antenna system is set to a desired band on a single wire interface.
  • DAC Digital-to Analog Converter
  • a system for distributing a plurality of satellite signals on a single interface in accordance with one or more embodiments of the present invention comprises an oscillator for down- converting the plurality of satellite signals to signals at an intermediate frequency, an Automatic Gain Controller (AGC) for gain controlling the signals at the intermediate frequency, an analog- to-digital (AJD) converter, coupled to the AGC, for receiving the signals at the intermediate frequency, wherein the A/D converter directly samples the signals at the intermediate frequency, and a Digital Signal Processor (DSP), coupled to the A/D converter, wherein a first output of the DSP is used to determine the intermediate frequency and a second output of the DSP is an input to the single interface.
  • AGC Automatic Gain Controller
  • AJD analog- to-digital converter
  • Such a system further optionally comprises a Digital-to-Analog Converter (DAC), coupled to the second output of the DSP, the first output of the DSP determining the intermediate frequency by controlling a frequency of the oscillator, the first output of the DSP driving a compensatory frequency shift by controlling a digital mixer internal to the DSP, the oscillator being a Dielectric Resonance Oscillator (DRO), the plurality of satellite signals being transmitted in a plurality of frequency bands, the plurality of frequency bands comprising a Ka-band and a Ku-band, the DRO down-converting the Ka-band to at least a first intermediate frequency band and the DRO down-converting the Ku-band to a second intermediate frequency band as convenient for A/D conversion, the A/D converter sampling the signals at the intermediate frequency at a rate greater than the Nyquist rate for the signals at the intermediate frequency, state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, and the diagnostic output comprising

Abstract

Systems and devices for controlling frequency drift in satellite broadcast systems. A receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (A/D) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.

Description

FREQUENCY DRIFT ESTIMATION FOR LOW COST OUTDOOR
UNIT
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates generally to satellite video systems, and in particular, to a method, apparatus, and article of manufacture for frequency drift estimation in satellite outdoor unit systems.
2. Description of the Related Art.
Satellite broadcasting of communications signals has become commonplace. Satellite distribution of commercial signals for use in television programming currently utilizes multiple feedhorns on a single Outdoor Unit (ODU) which supply signals to up to eight Integrated Receiver/Decoders (IRDs), e.g., set top boxes, on separate cables from a multiswitch.
FIG. 1 illustrates a typical satellite-based broadcast system of the related art.
System 100 uses signals sent from Satellite A (SatA) 102, Satellite B (SatB) 104, and Satellite C (SatC) 106 that are directly broadcast to an Outdoor Unit (ODU) 108 that is typically attached to the outside of a house 110. ODU 108 receives these signals and sends the received signals to IRD 112, which decodes the signals and separates the signals into viewer channels, which are then passed to monitor 114 for viewing by a user. There can be more than one satellite transmitting from each orbital location (slot). The orbital slots are typically designated by their longitude, so, for example, a satellite 102 located in the orbital slot at 101 degrees West Longitude (WL) is usually referred to as transmitting from "101." Satellite uplink signals 116 are transmitted by one or more uplink facilities 118 to the satellites 102-106 that are typically in geosynchronous orbit. Satellites 102-106 amplify and rebroadcast the uplink signals 116, through transponders located on the satellite, as downlink signals 120. Depending on the satellite 102-106 antenna pattern, the downlink signals 120 are directed towards geographic areas for reception by the ODU 108.
Each satellite 102-106 broadcasts downlink signals 120 in typically thirty-two (32) different frequencies, which are licensed to various users for broadcasting of programming, which can be audio, video, or data signals, or any combination. These signals are typically located in the Ku-band of frequencies, i.e., 11-18 GHz, but can also be broadcast in the Ka-band of frequencies, i.e., 18-40 GHz, but typically 20-30 GHz.
Within ODU 108, the downlink signals 120 are downconverted to lower frequencies using an oscillator and a mixer. Typically, the oscillator is a Dielectric Resonant Oscillator (DRO). If the DRO frequency drifts, the downconversion of the downlink signals 120 drifts as well, which makes processing of such downconverted signals more difficult. Further, as satellites 102-106 broadcast additional services and additional channels to viewers, as well as additional satellite signals present in such bandwidths, it will be more efficient to monitor and, if necessary, correct drifts in the DRO frequency.
SUMMARY OF THE INVENTION
To minimize the limitations in the prior art, and to minimize other limitations that will become apparent upon reading and understanding the present specification, systems and devices for controlling frequency drift in satellite broadcast systems are presented herein. A receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (A/D) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.
Such a system further optionally comprises the drift estimator driving a digital mixer within the DSP to compensate for the determined frequency drift, an output of the drift estimator being fed back to the oscillator to control the frequency drift of the oscillator, an automatic gain control coupled between the mixer and the A/D converter, the A/D converter sampling the signals at the intermediate frequency at a speed greater than 1 gigasample per second, the satellite signals being transmitted in at least the Ku-band of frequencies, the satellite signals being further transmitted in at least the Ka-band of frequencies, a Digital-to Analog Converter (DAC), coupled to the DSP, and an output of the DAC being mixed with a second oscillator, such that an output of the receiver antenna system is set to a desired band on a single wire interface.
A system for distributing a plurality of satellite signals on a single interface in accordance with one or more embodiments of the present invention comprises an oscillator for down- converting the plurality of satellite signals to signals at an intermediate frequency, an Automatic Gain Controller (AGC) for gain controlling the signals at the intermediate frequency, an analog- to-digital (AJO) converter, coupled to the AGC, for receiving the signals at the intermediate frequency, wherein the A/D converter directly samples the signals at the intermediate frequency, and a Digital Signal Processor (DSP), coupled to the A/D converter, wherein a first output of the DSP is used to determine the intermediate frequency and a second output of the DSP is an input to the single interface.
Such a system further optionally comprises a Digital-to- Analog Converter (DAC), coupled to the second output of the DSP, the first output of the DSP determining the intermediate frequency by controlling a frequency of the oscillator, the first output of the DSP driving a compensatory frequency shift by controlling a digital mixer internal to the DSP, the oscillator being a Dielectric Resonance Oscillator (DRO), the plurality of satellite signals being transmitted in a plurality of frequency bands, the plurality of frequency bands comprising a Ka-band and a Ku-band, the DRO down-converting the Ka-band to at least a first intermediate frequency band and the DRO down-converting the Ku-band to a second intermediate frequency band as convenient for A/D conversion, the A/D converter sampling the signals at the intermediate frequency at a rate greater than the Nyquist rate for the signals at the intermediate frequency, state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, and the diagnostic output comprising at least one of fault recognition, fault reporting, performance monitoring, installation aiding, and installation verification for the system.
Other features and advantages are inherent in the system disclosed or will become apparent to those skilled in the art from the following detailed description and its accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings in which like reference numbers represent corresponding parts throughout: FIG. 1 illustrates a typical satellite-based broadcast system of the related art;
FIG. 2 illustrates a typical Single Wire Multiswitch (SWM) of the related art; FIGS. 3A and 3B illustrate related LNB modules and an LNB module in accordance with one or more embodiments of the present invention, respectively;
FIG. 4 illustrates an Analog-to-Digital subsystem functionality in accordance with one or more embodiments of the present invention;
FIG. 5 illustrates a block diagram of the Digital Single Wire Multiswitch (DSWM) Channelizer in accordance with one or more embodiments of the present invention;
FIG. 6 illustrates a coarse granularity channelizer in accordance with one or more embodiments of the present invention; FIG. 7 illustrates an exemplary fine granularity channelizer embodiment in accordance with one or more embodiments of the present invention; and
FIG. 8 illustrates a block diagram of a frequency drift control system in accordance with one or more embodiments of the present invention.
DETAILED DESCRIPTION
In the following description, reference is made to the accompanying drawings which form a part hereof, and in which are shown, by way of illustration, several embodiments of the present invention. It is understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention.
Overview
Recent advances in high speed Analog to Digital (AIO) converters open up the possibility of direct A/D conversion of baseband or near baseband 500 MHz wide Satellite downlink signals. This allows for all-digital demultiplexing (demuxing) of one or more 500 MHz complexes or transponders and subsequent all-digital multiplexing (muxing) of a selected subset of these transponder channels onto a single wire interface for home distribution. With such a digital implementation, selected transponder baseband I/Q signals may be selected for direct demodulation, for subsequent home or multi-dwelling distribution over any suitable physical/network layer protocols.
By integrating the high-speed AJO hardware with computationally-efficient Digital Signal Processing (DSP) techniques, and adapting them specifically for the purposes of demuxing, muxing, and baseband I/Q conversion, one or more embodiments of the present invention provide significant commercial advantages over current analog designs. Further, simple brute force digital mimicry of known analog building blocks for demuxing/muxing/conversion processes are expected to lead to less commercially-viable designs.
No known previously proposed satellite home/MDU distribution design exists to create a practical all digital implementation of the demuxing, muxing, and direct digital demodulation (demod) interface. This specification proposes a number of embodiments of such designs which utilize computationally efficient techniques which allow for commercially viable all digital implementation of these functions.
The present invention allows for better overall performance of an embodiment of a Single Wire Multiswitch (SWM) architecture because the present invention allows for the distribution of more channels within the same bandwidth (i.e., single wire bandwidth) through tighter packing of channels. Distribution of additional channels allows for the support of additional IRDs, or the same number of IRDs with less wired bandwidth. Further, embodiments of the present invention allow for inexpensive provision of baseband I/Q signals for reduced cost integration of a significant portion of the current IRD. Further still, embodiments of the present invention allow for the ability to provide greater flexibility for future system designs, and the potential of a smaller footprint for the SWM into the current system. Embodiments of the present invention also allow for simpler integration and interfaces between the parts of the present system, by simplifying the interface of shared demodulation resources without expending any bandwidth. This simplification allows for future products, such as Home Gateway and Multi-Dwelling Unit (MDU) architectures, to become possible.
Digital SWM (DSWM)
FIG. 2 illustrates a typical Analog Single Wire Multiswitch. Hardware advances have increased A/D sampling rates in excess of 1 Gigasample/second
(1 GSPS) with a good Effective Number Of Bits (ENOB) and an adequate linearity performance figure. Advances in multi-rate Digital Signal Processing techniques coupled with nanometer Application-Specific Integrated Circuit (ASIC) processes allow applications with significant signal processing capabilities. These factors make it possible to make an all-digital replacement for the demux and mux functions of the Single Wire Multiswitch (SWM). Further, these technological advances allow for a baseband and/or near baseband digital I/Q interface for cost- effective integration of a significant portion of the IRD front end functionality. One or more embodiments of the present invention provide a digital replacement for the hardware shown in FIG. 2. FIG. 2 illustrates SWM 200, where SWM 200 is fed by four composite signals 202-208, specifically LNBl 202, LNB2 204, LNB3 206, and LNB4 208, which are produced by the LNB module 300 hardware shown in FIG. 3A.
Each LNB signal 202-208, as shown in FIG. 3A, comprises multiple (e.g., three) stacked 500 MHz bandwidth signals, generated from downlink signals 120 and received at various orbital slots. Ku-band signals 302 are from satellites at the 119 WL slot, Ku-band signals 304 are from satellites at the 110 WL slot, Ka-band signals 306 are from satellites at the 102.8 (also referred to as 103) WL slot, Ku-band signals 308 are from satellites at the 101 WL slot, and Ka-band signals 302 are from satellites at the 99.2 (also referred to as 99) WL slot. Combinations of these signals, based on their polarization and transmission frequencies, are used to generate LNB signals 202-208.
After down-conversion within module 300, the Ku-band signals 302, 304, and 308 are down-converted to an Intermediate Frequency (IF) band, 500 MHz wide, in the frequency range of 950-1450 MHz. The Ka-band signals 306 and 310 are down-converted into two different 500 MHz wide bandwidths, namely the 250-750 MHz bandwidth (known as Ka-LO IF band or Ka-B IF band) and the 1650-2150 MHz bandwidth (known as Ka-HI IF band or Ka-A IF band), and are combined in various combinations to form signals 202-208
The SWM 200 shown in FIG. 2 selects any nine 40 MHz pieces of spectrum from LNBl 202 through LNB4 208 and stacks them to form a single composite signal called the channel stacked output 210. The nine 40MHz channels are typically located on 102 MHz centers and range from 974 MHz to 1790 MHz (i.e., the channels are at 974, 1076, 1178, 1280, 1382, 1484, 1586, 1688, and 1790 MHz, respectively).
Coarse Granularity Design
FIG. 3B illustrates an embodiment an LNB structure corresponding to a Digital SWM Design in accordance with the present invention.
The SWM module 300 is modified into module 312, where signals 302-310 are combined into different signals that are to be used as inputs to a modified SWM. Rather than stacking 1500 MHz into a single signal, as is done with signals 202-208, a larger number of outputs 312-326 are used. Although eight outputs 312-326 are shown, a larger or smaller number of outputs 312- 326 are possible without departing from the scope of the present invention.
As shown in FIG. 3B, LNBl signal 312, LNB2 signal 314, LNB5 signal 320, and LNB6 signal 322 each comprise two 500 MHz signals, each 500 MHz signal corresponding to a Ka-LO band signal and a Ka-HI band signal. This arrangement is appropriate if the A/D has enough front end bandwidth to subsample the Ka-Hi band in its 2nd Nyquist Band. Alternatively, separate independent IF conversion for the Ka-Lo and Ka-Hi can be provided for more traditional 1st Nyquist band sampling of each signal. LNB3 signal 316, LNB4 signal 318, LNB7 signal 324, and LNB8 signal 326, on the other hand, are 500 MHz signals, each corresponding to a Ku-band signal. To facilitate A/D conversion, the local oscillators 328 can be modified so that each of the signals 312-326 can have a desired and, possibly, different tunable starting frequency from 10 to 100 MHz, or beyond these limits if desired. Additional mixing can be added to achieve an offset frequency start for one or more of the signals 312-326 if desired. It is also possible within the scope of the present invention to implement tuning for signals 312-326 within the digital domain if desired.
FIG. 4 illustrates an embodiment of the Analog-to-Digital subsystem functionality of the present invention.
FIG. 4 shows the A/D subsystem 400 functions, where the sampling frequency Fs is adjustable, typically from 1.02 GHz to 1.2 GHz, but other frequencies and ranges are possible within the scope of the present invention. Each signal 312-326 is placed through a filter 402, and then into an A/D converter 404, which produce the output signals 406-428. The typical maximal sampling rate of the A/D converters 404, FsMAX, is typically 1.35GHz, but other rates are possible without departing from the scope of the present invention. The Ka HI signals are typically sub-sampled, so the analog paths should have a useable bandwidth of FsMAX + 500 MHz, which is typically 1.85 GHz. Alternatively if separate IF conversion is provided for the Ka-Hi signal then traditional 1st Nyquist band sampling and Lo-Pass anti-alias filters would be employed.
FIG. 5 illustrates a block diagram of the DSWM Channelizer in accordance with one or more embodiments of the present invention.
Each input "x" 500, 502, etc., receives one of the A/D converter 404 outputs 406-428, and there can be extra inputs x 500, 502, etc., to allow for expansion of the system. Each typical input x 500 is typically channelized into uniformly spaced K filters 504. The portion k 506 of the K filters 504 actually utilized may be different for different LNB paths, and, typically, k = 12 for Ka HI, k = 12 for Ka LO, and k = 16 for Ku. L, the number of filter bands on the output side, is set to be equal to the number of stacked carriers desired at the stacked output 210. There are many embodiments within the scope of the present invention that can create computationally efficient DSP architectures. Another example embodiment of the present invention uses multi-rate poly phase techniques and takes advantage of the correspondence between the complex mixing and the Fast Fourier Transform (FFT), as shown in FIG. 6. FIG. 6 illustrates a coarse granularity channelizer in accordance with one or more embodiments of the present invention.
In FIG. 6, system 600 shows inputs 406-428, each entering a Real to Complex Hubert transformer 600. Other types of Real to Complex transforms of the signal inputs 406-428 are also possible within the scope of the present invention. The K filters 604 for each of the inputs 406-428 are set to 16, but other settings are possible within the scope of the present invention, including different values for K and x for each input 406-428. If the transponder count and spacing are uniform and well known, then K can be set to the number of transponders, etc. If, however, the number of transponders varies from satellite to satellite and/or the spacing of these transponders is not uniform, then a number of filters 604 greater than the maximum number of transponders to be encountered is typically used to allow for expansion. Further, the filters are then expanded or contracted by slight adjustments in the sampling frequency and by slight shifts in the down-converter LO frequency used in the LNB. By adjustment of both the down- converter LO of the LNB and sampling rate, any channel spacings can be accommodated in any of the LNB outputs. The signals 406-428, after being filtered by filters 602 are subjected to Fast Fourier
Transforms (FFT) in FFTs 606, and then selected, reordered, and combined in multiplexer 608. The combined signal is further processed to generate stacked output 210. Alternatively, the present invention can use a non-maximally decimated filter bank of overlapping filters. This approach, along with the added technique of near-perfect reconstruction techniques simplify the fine granularity design.
A choice of L = 32 and K =16 are illustrative only. The choice of the power of 2 composite K and L is chosen to simplify the FFT hardware implementation. Other approaches or arrangements may also be used within the scope of the present invention.
ADC ENOB Considerations
Consider any one of the 500 MHz LNB signals 406-428. Since each signal is a composite of many signals, each signal is approximately Gaussian distributed. Given this approximation, the attack point on the ADC can be set low enough so that probability of the input exceeding the full scale deflection is controlled and thereby minimize the clipping noise effects. Similarly the attack point can be set high enough so that the ADC is driven hard enough to minimize the effects of quantization noise. The balancing of these two noise affects yields an optimal attack point (sometimes referred to as backoff point). For any given backoff point then the ADC Effective Number of Bits (ENOB) will determine the Signal to Quantization Noise Floor. For anticipated transponder loadings an ENOB of 8 bits is more than sufficient. Since A/D are available at approximately this ENOB while operating well in excess of 1 Gsps, the current state of the art in ADCs is sufficient to implement the designs described by this invention. However, an accounting of the Noise-Power Ratio of the finite word processing and additional details of the noise bandwidth and system settings may allow the ENOB to be relaxed from a 8 bit setting and still be within the scope of the present invention. Fine Granularity Design
FIG. 7 illustrates a fine granularity channelizer implementation in accordance with one or more embodiments of the present invention.
A fine granularity design using perfect or near perfect reconstruction polyphase filtering techniques has advantages over the coarse granularity approach. . For such an approach, the spectrum of each of the incoming 500 MHz blocks is subdivided much more finely than in the coarse granularity design. Where in the coarse granularity design the goal is to create a number of filters greater than or equal to the maximum number of expected transponders, in the fine granularity design the goal is to divide up the spectrum into smaller pieces. This can be done in such a way that the fine pieces of spectrum can be "glued" back together to yield a nearly perfect reconstruction of any arbitrary spectral bandwidth within the granularity specified for the design. Employment of non-maximal decimation techniques can be used to simplify filter design if desired. An illustrative design for a fine granularity system is shown in FIG. 7.
The system 700 shown in FIG. 7 has four output signals 702, 704, 706, and 708. Outputs 702 and 704 are typically used to create two 500 MHz blocks of single wire bandwidth. Outputs 702 and 704 can then be power combined onto a single wire interface and thus replicate the output of related SWM designs, except that they provide more channels within the same physical bandwidth.
The other outputs 706 and 708 depicts two illustrative embodiments that include shared demod assets that do not expend any of the Single Wire Bandwidth. Other embodiments are possible within the scope of the present invention. Optionally, only one output 706 or 708 can be implemented, or other embodiments can be implemented alone or in any combination, without departing from the scope of the present invention. Output 706 illustrates an approach having an additional internal single wire interface which drives conventional receiver/demod inputs.
Output 708 illustrates an approach where the receiver portion of the receiver demod chips can be eliminated at the same time as the last up-conversion of the processed signals. These chips correspond to I/Q near baseband demodulation. Other configurations are possible if some of the output polyphase filtering is incorporated directly on the demod chip for individual true baseband I/Q processing. In both outputs 706 and 708, the output of the shared demod resources is Satellite Communicator Identification Code (SCID) filtered data which is networked onto any suitable physical layer and/or network layer protocols for distribution throughout the house or Multiple Dwelling Unit (MDU). The outputs 706 and 708 are Internet Protocol (IP) type outputs, or similar, that can be output over ethernet cabling, local area networks, RF, or other similar interfaces as desired, without departing from the scope of the present invention.
PRO Frequency Drift Control
FIG. 8 illustrates a functional block diagram of processing of one 500MHz band in accordance with one or more embodiments of the present invention.
Advances in Digital Signal Processing (DSP) techniques, specifically, the speed at which DSP techniques can now take place, allow for more efficient bandwidth packing of signals on a single wire interface between ODU 108 and receiver 112. However, in order to take advantage of this tighter signal packing, the frequency stability of frequency sources, in this case, the frequency source used to initially down-convert signals 120 into an intermediate frequency, must be similarly improved. The present invention allows for estimation of frequency drift of the frequency source used for down-conversion, as well as allowing for the ability to measure frequency domain errors which will allow for diagnostic feedback on the state of system 100.
As shown in FIG. 8, signals 120 are received at ODU 108, and then are passed on to receiver 112. Within ODU 108, an antenna 800 receives the signals 120 at both Ku-band and Ka-band (e.g., approximately 20 GHz), which are mixed at mixer 802 with the output of DRO 804. This mixing process results in an output of mixer 802 of the sum and difference frequencies of signals 120 and DRO 804, and the frequency of DRO 804 is chosen to down-convert signals 120 to a frequency convenient for A/D conversion. These signals are then typically filtered through a Band Pass Filter (BPF) 808 to remove harmonics and other unwanted signals, and then typically passed to Automatic Gain Control (AGC) 810 circuitry to normalize the signals 806 to a common signal strength. Such a common strength is typically desirable to properly excite Analog-to-Digital (A/D) converter 812 to set the attack point as previously described in the ENOB Considerations discussion. A/D 812 is a high-speed A/D converter, in that it can run at 1 Gigasample per second
(GSPS) or higher. Such speed is needed because the typical bandwidth of the signals 806 is 500 MHz, and to sample at the minimum Nyquist rate for such signals requires a minimum of twice the bandwidth, or 1 GSPS. A/D 812, thanks to recent advances in A/D design, can now achieve 1 GSPS rates, and higher. Once digitized by A/D 812, Digital Signal Processor (DSP) 814 processes the signals and converts them back to analog signals in the Digital-to-Analog
Converter (DAC) 816. Such signals are then mixed at mixer 818 with a local oscillator 820 and forwarded on to receiver 112. Optionally, this last mixer can be avoided if a DAC with sufficient BW is employed such that it can directly cover the desired single wire interface band.
Within DSP 814, the signals can be sent to a drift estimator 822, where drift of the frequency of signals 806 can be sensed. Sensing drifts from various sources are achievable within the scope of the present invention, e.g., drifts which affect single carriers within a given bandwidth of signals or drifts which affect an aggregate of carriers, etc., however, the primary cause of drift of signals 806 is the DRO 804 frequency drift with temperature and age. DRO 804 is located at the dish antenna 800 of ODU 108, and as the sun heats the dish antenna 800, DRO 804 warms up which causes drift, and as the sun goes down dish antenna 800 cools down, cooling down DRO 804, again causing drift in frequency. Further, aging of the DRO 804 will also cause a frequency drift in the DRO 804 output. The drift estimator 822 can be of several varieties. One solution that can be used for drift estimator 822 is to create a discriminator based on a matched filter design, such that the expected type and distribution of transponders within the aggregate bandwidth of signals 806 is sensed. Such a discriminator can be developed for individual transponders if desired, or the edges of the bandwidth can be sensed. For transponders with symmetrical properties, the discriminator can be a matched filter with a sign reversal about the center frequency, however, if the purpose is to drive the average drift of the DRO 804 to zero, a matched filter for all of the transponders within the aggregate bandwidth can be utilized. Although the drift estimator algorithm may result in a biased estimate of each transponder's frequency that is down-converted by the DRO 804, the DRO 804 is tuned by the aggregate of the transponder drift discriminants (biased or not) and will therefore tend to average out the biasing effects due to any individual transponder gain slopes and ripples.
The present invention also allows for system 100, via ODU 108 (also called a Single- Wire Multiswitch ODU or SWM-ODU) to recognize large frequency deviations and frequency trends over the life of ODU 108. As DRO 804 frequencies drift over the life of DRO 804, the present invention can provide not only feedback to DRO 804, but to system providers via receiver 112 callbacks or other communications between receiver 112 and system providers. Receivers 112 typically comprise a high-speed internet or other interface to allow communications between the system provider and individual receivers 112; reporting system 100 health issues can now, through the use of the present invention, be undertaken by processors in receiver 112 and/or DSP 814.
The outputs of drift estimator 822 are then converted to analog voltages in DAC 824, and then fed back to DRO 804 via a control input 826 to DRO 804. In essence, DRO 804 acts like a Voltage Controlled Oscillator (VCO) at this point, where the voltage applied at 826 controls the frequency output of DRO 804.
Although the use of DSP outputs to sense and correct frequency drift faults is emphasized herein, other uses of DSP 814 outputs to recognize other faults and to take other corrective actions are possible within the scope of the present invention. In particular, by virtue of the architecture of the described processing key diagnostic information is available for other diagnostics. A mixed signal ASIC will typically include the AGCs 810, ADCs 812, DSP 814, DACs 816, and a general purpose processor implementing the Drift Estimator 822 matched filter discriminant. Thus the general purpose processor has access to information regarding the state of each of these subsystems. Beyond determining the frequency drift, the matched filter results coupled with knowledge of the AGC states provides important diagnostic information if no match is found over the possible range of drift frequencies of a given expected transponder. The system can thereby recognize the absence of expected transponders and can report this fault. This fault represents a fault in system 100 to deliver the missing transponder to the ODU 108. The failure of the match filter to find a match for any transponder in a given 500MHz band indicates the potential failure of one of the 500MHz signal paths 312,314,318,320, 322,324, and 326 or subsequent processing these signal paths indicating a potential hardware failure in the ODU 108. In particular, if it is known that other ODUs 108 at other sites (homes) in the near vicinity of a given ODU 108 are not reporting faults, then it can be concluded by system 100 that the fault is isolated to the given ODU ("lone ODU")- In contrast, if all ODUs 108 in the vicinity of a given ODU 108 all report faults on many 500MHz bands over a given short period of time followed by a complete recovery, the likely cause of the event is a weather generated event. In particular, if a collocated group of ODUs report faults occurring primarily or for longer periods of time on the Ka bands as opposed to the Ku bands then a weather event is very likely since weather affects Ka signals much more severely then the Ku signals. If a lone ODU 108 reports failures on many of its signal paths for extended periods of time then ODU 108 mis-pointing is indicated. During installation, the diagnostics described also have value. Analyzing a combination of matched filter and AGC results, information to aid in the initial ODU antenna pointing and verification of the final installation can be provided. The above examples, e.g., the use of state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, where the diagnostic output comprises at least one of fault recognition, fault reporting, performance monitoring, installation aiding, and installation verification for the system 100, are provided as examples of the class of diagnostics and installation verification aids possible by analysis of data related to the state of the subsystems of the given architecture. Any such diagnostics or installation aids derived from such state information is within the scope of this invention.
Although discussed with respect to voltage control of DRO 804, other methods of control of signals 806, and the effects of DRO 804 drift, can be accomplished with the present invention. For example, and not by way of limitation, a digital compensation within DSP 814 of the frequency offset, once estimated by drift estimator 822, can also be achieved via feedback between drift estimator 822 and DSP 814. Conclusion
The present invention discloses systems and devices for controlling frequency drift in satellite broadcast systems. A receiver antenna system for a direct broadcast satellite signal communications system in accordance with one or more embodiments of the present invention comprises an oscillator, a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency, an analog-to-digital (AJO) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-real-time to a digital data stream, a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream, and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.
Such a system further optionally comprises the drift estimator driving a digital mixer within the DSP to compensate for the determined frequency drift, an output of the drift estimator being fed back to the oscillator to control the frequency drift of the oscillator, an automatic gain control coupled between the mixer and the A/D converter, the A/D converter sampling the signals at the intermediate frequency at a speed greater than 1 gigasample per second, the satellite signals being transmitted in at least the Ku-band of frequencies, the satellite signals being further transmitted in at least the Ka-band of frequencies, a Digital-to Analog Converter (DAC), coupled to the DSP, and an output of the DAC being mixed with a second oscillator, such that an output of the receiver antenna system is set to a desired band on a single wire interface.
A system for distributing a plurality of satellite signals on a single interface in accordance with one or more embodiments of the present invention comprises an oscillator for down- converting the plurality of satellite signals to signals at an intermediate frequency, an Automatic Gain Controller (AGC) for gain controlling the signals at the intermediate frequency, an analog- to-digital (AJD) converter, coupled to the AGC, for receiving the signals at the intermediate frequency, wherein the A/D converter directly samples the signals at the intermediate frequency, and a Digital Signal Processor (DSP), coupled to the A/D converter, wherein a first output of the DSP is used to determine the intermediate frequency and a second output of the DSP is an input to the single interface.
Such a system further optionally comprises a Digital-to-Analog Converter (DAC), coupled to the second output of the DSP, the first output of the DSP determining the intermediate frequency by controlling a frequency of the oscillator, the first output of the DSP driving a compensatory frequency shift by controlling a digital mixer internal to the DSP, the oscillator being a Dielectric Resonance Oscillator (DRO), the plurality of satellite signals being transmitted in a plurality of frequency bands, the plurality of frequency bands comprising a Ka-band and a Ku-band, the DRO down-converting the Ka-band to at least a first intermediate frequency band and the DRO down-converting the Ku-band to a second intermediate frequency band as convenient for A/D conversion, the A/D converter sampling the signals at the intermediate frequency at a rate greater than the Nyquist rate for the signals at the intermediate frequency, state information from at least one of the AGC, the ADC, the DSP, and the DAC providing a diagnostic output for the system, and the diagnostic output comprising at least one of fault recognition, fault reporting, performance monitoring, installation aiding, and installation verification for the system.
The foregoing description of the preferred embodiment of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but by the claims appended hereto and the full range of equivalents of the claims appended hereto.

Claims

WHAT IS CLAIMED IS:
1. A receiver antenna system for a direct broadcast satellite signal communications system, comprising: an oscillator; a mixer, coupled to the oscillator, for converting satellite signals at a first frequency to signals at an intermediate frequency; an analog-to-digital (A/D) converter, coupled to the mixer, for receiving the signals at the intermediate frequency and for converting the signals at the intermediate frequency at near-realtime to a digital data stream; a Digital Signal Processor (DSP), coupled to the A/D converter, for processing the digital data stream; and a drift estimator, coupled to the DSP, the drift estimator determining a frequency drift of the oscillator, wherein the receiver antenna system corrects the frequency drift of the oscillator using the determined frequency drift.
2. The receiver antenna system of claim 1, wherein the drift estimator drives a digital mixer within the DSP to compensate for the determined frequency drift.
3. The receiver antenna system of claim 1 , wherein an output of the drift estimator is fed back to the oscillator to control the frequency drift of the oscillator.
4. The receiver antenna system of claim 1, further comprising an automatic gain control coupled between the mixer and the A/D converter.
5. The receiver antenna system of claim 1 , wherein the A/D converter samples the signals at the intermediate frequency at a speed greater than 1 gigasample per second.
6. The receiver antenna system of claim 1, wherein the satellite signals are transmitted in at least the Ku-band of frequencies.
7. The receiver antenna system of claim 6, wherein the satellite signals are further transmitted in at least the Ka-band of frequencies.
8. The receiver antenna system of claim 7, further comprising a Digital-to Analog Converter (DAC), coupled to the DSP.
9. The receiver antenna system of claim 8, wherein an output of the DAC is mixed with a second oscillator, such that an output of the receiver antenna system is set to a desired band on a single wire interface.
10. A system for distributing a plurality of satellite signals on a single interface, comprising: an oscillator for down-converting the plurality of satellite signals to signals at an intermediate frequency; an Automatic Gain Controller (AGC) for gain controlling the signals at the intermediate frequency; an analog-to-digital (A/D) converter, coupled to the AGC, for receiving the signals at the intermediate frequency, wherein the A/D converter directly samples the signals at the intermediate frequency; and a Digital Signal Processor (DSP), coupled to the A/D converter, wherein a first output of the DSP is used to determine the intermediate frequency and a second output of the DSP is an input to the single interface.
11. The system of claim 10, further comprising a Digital -to-Analog Converter (DAC), coupled to the second output of the DSP.
12. The system of claim 10, wherein the first output of the DSP determines the intermediate frequency by controlling a frequency of the oscillator.
13. The system of claim 10, wherein the first output of the DSP drives a compensatory frequency shift by controlling a digital mixer internal to the DSP.
14. The system of claim 12, wherein the oscillator is a Dielectric Resonance Oscillator (DRO).
15. The system of claim 10, wherein the plurality of satellite signals are transmitted in a plurality of frequency bands.
16. The system of claim 15, wherein the plurality of frequency bands comprises a Ka- band and a Ku-band.
17. The system of claim 16, wherein the DRO down-converts the Ka-band to at least a first intermediate frequency band and the DRO down-converts the Ku-band to a second intermediate frequency band as convenient for A/D conversion.
18. The system of claim 10, wherein the A/D converter samples the signals at the intermediate frequency at a rate greater than the Nyquist rate for the signals at the intermediate frequency.
19. The system of claim 11 , wherein state information from at least one of the AGC, the ADC, the DSP, and the DAC provide a diagnostic output for the system.
20. The system of claim 19, wherein the diagnostic output comprises at least one of fault recognition, fault reporting, performance monitoring, installation aiding, and installation verification for the system.
PCT/US2010/020246 2009-01-06 2010-01-06 Frequency drift estimation for low cost outdoor unit WO2010080823A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
MX2011007027A MX2011007027A (en) 2009-01-06 2010-01-06 Frequency drift estimation for low cost outdoor unit.
BRPI1006912A BRPI1006912A2 (en) 2009-01-06 2010-01-06 frequency drift estimation for low cost outdoor unit

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US14286509P 2009-01-06 2009-01-06
US61/142,865 2009-01-06

Publications (1)

Publication Number Publication Date
WO2010080823A1 true WO2010080823A1 (en) 2010-07-15

Family

ID=42060947

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2010/020246 WO2010080823A1 (en) 2009-01-06 2010-01-06 Frequency drift estimation for low cost outdoor unit

Country Status (5)

Country Link
US (3) US8229383B2 (en)
AR (1) AR074992A1 (en)
BR (1) BRPI1006912A2 (en)
MX (1) MX2011007027A (en)
WO (1) WO2010080823A1 (en)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009053910A2 (en) 2007-10-22 2009-04-30 Mobileaccess Networks Ltd. Communication system using low bandwidth wires
WO2011059422A1 (en) * 2009-11-13 2011-05-19 Thomson Licensing Algorithm for improving transponder scanning in a satellite set-top box
FR2961054A1 (en) * 2010-06-08 2011-12-09 Sigfox Wireless METHOD FOR USING SHARED FREQUENCY RESOURCE, METHOD FOR CONFIGURING TERMINALS, TERMINALS, AND TELECOMMUNICATIONS SYSTEM
CA2825707A1 (en) * 2011-01-21 2012-07-26 Tommy Yu Systems and methods for selecting digital content channels using low noise block converters including digital channelizer switches
EP2676392A4 (en) 2011-02-16 2016-10-12 Entropic Communications Inc Optical converter with adc based channelizer for optical lnb system
EP2829152A2 (en) 2012-03-23 2015-01-28 Corning Optical Communications Wireless Ltd. Radio-frequency integrated circuit (rfic) chip(s) for providing distributed antenna system functionalities, and related components, systems, and methods
US20140293894A1 (en) * 2013-03-28 2014-10-02 Coming Optical Communications Wireless, Ltd. Distributing dynamically frequency-shifted intermediate frequency (if) radio frequency (rf) communications signals in distributed antenna systems (dass), and related components, systems, and methods
US9641361B2 (en) * 2013-11-19 2017-05-02 Electronics And Telecommunications Research Institute Sub-sampling receiver
US9461651B2 (en) * 2014-01-30 2016-10-04 Maxlinear, Inc. Detection and compensation of dielectric resonator oscillator frequency drift
US9565675B2 (en) 2014-09-26 2017-02-07 Hughes Network Systems L.L.C. Fixed intermediate frequency signal with tuned low frequency local oscillator reference for linear transmitter
US9591595B2 (en) * 2014-09-30 2017-03-07 Hughes Network Systems, Llc Inroute automatic gain control detection of outroute interference
US20160127122A1 (en) * 2014-11-04 2016-05-05 Maxlinear, Inc. Quadricorrelator carrier frequency tracking
KR101589872B1 (en) * 2015-04-21 2016-02-01 주식회사 아이두잇 Flat antenna and system for transporting satellite signal comprising such flat antenna
US9461693B1 (en) 2015-04-23 2016-10-04 The Directv Group, Inc. Systems and methods for frequency and bandwidth optimization with a single-wire multiswitch device
EP3236600A1 (en) * 2016-04-18 2017-10-25 Advanced Digital Broadcast S.A. A low-noise block downconverter and method for the same
EP3632067B1 (en) * 2018-08-20 2023-10-25 Waviot Integrated Systems, LLC Method and system for receiving telemetry messages over rf channel
CN109587473A (en) * 2018-12-04 2019-04-05 安徽站乾科技有限公司 A kind of self detection device of the failure of satellite TV system
US11342687B1 (en) * 2021-04-20 2022-05-24 Bae Systems Information And Electronic Systems Integration Inc. Endfire antenna structure on an aerodynamic system

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6173164B1 (en) * 1997-09-15 2001-01-09 Wireless Access Method and apparatus for wide range automatic frequency control
GB2354650A (en) * 1999-06-25 2001-03-28 Nec Corp Automatic frequency control circuit
US6463266B1 (en) * 1999-08-10 2002-10-08 Broadcom Corporation Radio frequency control for communications systems
US20080064355A1 (en) * 2006-09-13 2008-03-13 Ilan Sutskover Method and apparatus for efficiently applying frequency correction

Family Cites Families (199)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3581209A (en) 1968-09-17 1971-05-25 Arie Zimmerman Cable television program capacity enhancement
GB1276790A (en) 1970-03-20 1972-06-07 Vaisala Oy Improvements in devices by which antennae are automatically selected from arrays thereof and connected to radio receivers
US4064460A (en) 1974-03-16 1977-12-20 Communications Patents Limited Coaxial wired broadcasting system with tone responsive program selectors
JPS5823978B2 (en) 1975-11-11 1983-05-18 ソニー株式会社 Chuyuna
DE2951512A1 (en) 1979-12-20 1981-07-02 Siemens AG, 1000 Berlin und 8000 München BROADBAND SWITCHING SYSTEM
US4538175A (en) 1980-07-11 1985-08-27 Microdyne Corporation Receive only earth satellite ground station
US4403343A (en) 1980-09-30 1983-09-06 Clarion Co., Ltd. Diversity receiver
US4354167A (en) 1980-12-08 1982-10-12 501 Centre De Recherche Industrielle Du Quebec Multi-subscriber differentiation and distribution switching system having interchangeable differentiating circuits
NL8103064A (en) 1981-06-25 1983-01-17 Philips Nv COMMON AERIAL DEVICE FOR THE RECEPTION AND DISTRIBUTION OF TV AND DIGITAL AUDIO SIGNALS.
US4397037A (en) 1981-08-19 1983-08-02 Rca Corporation Diplexer for television tuning systems
JPS5861547U (en) 1981-10-19 1983-04-25 デイエツクスアンテナ株式会社 satellite receiver
US4545075A (en) 1981-11-18 1985-10-01 Times Fiber Communications, Inc. Satellite block transmission using wideband fiber optic links
NL8105609A (en) 1981-12-14 1983-07-01 Philips Nv COMMON AERIAL / DEVICE.
JPS5915335A (en) 1982-07-15 1984-01-26 Maspro Denkoh Corp Satellite broadcast receiving device
JPS5957534A (en) 1982-09-27 1984-04-03 Alps Electric Co Ltd Indoor unit of receiver for satellite broadcast
US4530008A (en) 1983-10-03 1985-07-16 Broadband Technologies, Inc. Secured communications system
DE3375351D1 (en) 1983-10-21 1988-02-18 Ant Nachrichtentech Process for the transmission of information services by satellites
AU576787B2 (en) 1983-11-07 1988-09-08 Sony Corporation Satellite to cable television interface
JPS60149227A (en) 1984-01-13 1985-08-06 Sony Corp Shf receiver
US4761827A (en) 1984-09-17 1988-08-02 Satellite Technology Services, Inc. Polarity switch for satellite television receiver
SE8406489L (en) 1984-12-19 1986-06-20 Nordspace Ab television reception
US4672687A (en) 1985-01-29 1987-06-09 Satellite Technology Services, Inc. Polarity switch for satellite television receiver
US4903031A (en) 1985-03-26 1990-02-20 Trio Kabushiki Kaisha Satellite receiver
US4723320A (en) 1985-03-28 1988-02-02 Satellite Technology Services, Inc. Dual communication link for satellite TV receiver
FR2589012B1 (en) 1985-06-28 1988-06-10 Hitachi Ltd PARABOLIC ANTENNA AND MANUFACTURING METHOD THEREOF
US4656486A (en) 1985-07-12 1987-04-07 Turner Allan L Satellite TV dish antenna support
JPH07107966B2 (en) 1985-07-18 1995-11-15 株式会社東芝 Switch distribution device
CA1262572A (en) 1985-10-01 1989-10-31 Masayoshi Hirashima Satellite receiver
JPH0666707B2 (en) 1985-10-21 1994-08-24 ソニー株式会社 Receiving machine
US4761825A (en) 1985-10-30 1988-08-02 Capetronic (Bsr) Ltd. TVRO earth station receiver for reducing interference and improving picture quality
US4667243A (en) 1985-10-31 1987-05-19 Rca Corporation Television receiver for direct broadcast satellite signals
US4663513A (en) 1985-11-26 1987-05-05 Spectra-Physics, Inc. Method and apparatus for monitoring laser processes
US4813036A (en) 1985-11-27 1989-03-14 National Exchange, Inc. Fully interconnected spot beam satellite communication system
US4785306A (en) 1986-01-17 1988-11-15 General Instrument Corporation Dual frequency feed satellite antenna horn
US4945410A (en) 1987-02-09 1990-07-31 Professional Satellite Imaging, Inc. Satellite communications system for medical related images
US4885803A (en) 1987-03-17 1989-12-05 Lawrence W. Hermann System and method for controlling a plurality of electronic entertainment devices
CA1329640C (en) 1987-07-24 1994-05-17 Miyoshi Yamauchi Outdoor unit low noise converter for satellite broadcast reception use
US4876736A (en) 1987-09-23 1989-10-24 A. C. Nielsen Company Method and apparatus for determining channel reception of a receiver
US5235619A (en) 1990-03-20 1993-08-10 Scientific-Atlanta, Inc. Cable television radio frequency subscriber data transmission apparatus and rf return method
JPH0243822A (en) 1988-08-03 1990-02-14 Toshiba Corp Television tuner
KR900004119A (en) 1988-08-09 1990-03-27 안시환 LNB for simultaneous reception of C / ku-band satellite broadcasting
NL8901460A (en) 1989-06-08 1991-01-02 Philips Nv RECEIVER FOR TERRESTRIAL AM AND SATELLITE FM TV BROADCASTS.
FR2649570B1 (en) 1989-07-04 1991-09-20 Thomson Composants Microondes SYSTEM FOR RECEIVING TRANSFERRED TV SIGNALS BY SATELLITES
US5073930A (en) 1989-10-19 1991-12-17 Green James A Method and system for receiving and distributing satellite transmitted television signals
FR2665319B1 (en) 1990-07-30 1993-08-20 Cgv Comp Gen Videotech DEVICE FOR DISTRIBUTING VIDEO AND / OR AUDIO SIGNALS BETWEEN SEVERAL RECEIVERS.
US5587734A (en) 1990-09-28 1996-12-24 Ictv, Inc. User interface for selecting television information services through pseudo-channel access
US5526034A (en) 1990-09-28 1996-06-11 Ictv, Inc. Interactive home information system with signal assignment
JP2778293B2 (en) 1991-07-04 1998-07-23 ソニー株式会社 Satellite broadcast receiving system and switching distributor
JPH0583153A (en) 1991-09-19 1993-04-02 Toshiba Corp Broad band tuning circuit
US5289272A (en) 1992-02-18 1994-02-22 Hughes Aircraft Company Combined data, audio and video distribution system in passenger aircraft
CN1047490C (en) 1992-08-19 1999-12-15 皇家菲利浦电子有限公司 Television signal cable distribution system and assembly of elements for constituting such a system
US5521631A (en) 1994-05-25 1996-05-28 Spectravision, Inc. Interactive digital video services system with store and forward capabilities
US5649318A (en) 1995-03-24 1997-07-15 Terrastar, Inc. Apparatus for converting an analog c-band broadcast receiver into a system for simultaneously receiving analog and digital c-band broadcast television signals
CA2157139A1 (en) 1994-09-01 1996-03-02 Thomas C. Weakley Multiple beam antenna system for simultaneously receiving multiple satellite signals
FR2730372A1 (en) 1995-02-08 1996-08-09 Philips Electronics Nv PAY TELEVISION METHOD
US5805975A (en) 1995-02-22 1998-09-08 Green, Sr.; James A. Satellite broadcast receiving and distribution system
US6122482A (en) 1995-02-22 2000-09-19 Global Communications, Inc. Satellite broadcast receiving and distribution system
US5892910A (en) 1995-02-28 1999-04-06 General Instrument Corporation CATV communication system for changing first protocol syntax processor which processes data of first format to second protocol syntax processor processes data of second format
JPH08314979A (en) 1995-03-13 1996-11-29 Matsushita Electric Ind Co Ltd Method and device for displaying program information on display
US5793413A (en) 1995-05-01 1998-08-11 Bell Atlantic Network Services, Inc. Wireless video distribution
US5708961A (en) 1995-05-01 1998-01-13 Bell Atlantic Network Services, Inc. Wireless on-premises video distribution using digital multiplexing
US5574964A (en) 1995-05-30 1996-11-12 Apple Computer, Inc. Signal distribution system
US5675390A (en) 1995-07-17 1997-10-07 Gateway 2000, Inc. Home entertainment system combining complex processor capability with a high quality display
JP3572595B2 (en) 1995-07-21 2004-10-06 ソニー株式会社 Electronic program guide display control apparatus and method
US5864747A (en) 1995-08-24 1999-01-26 General Dynamics Information Systems, Inc. Data bridge
US5617107A (en) 1995-09-01 1997-04-01 Perfect Ten Antenna Co. Inc. Heated microwave antenna
US5886732A (en) 1995-11-22 1999-03-23 Samsung Information Systems America Set-top electronics and network interface unit arrangement
US6005861A (en) 1995-11-22 1999-12-21 Samsung Electronics Co., Ltd. Home multimedia network architecture
US5805806A (en) 1995-12-18 1998-09-08 Intel Corporation Method and apparatus for providing interactive networking between televisions and personal computers
EP0781048A1 (en) 1995-12-20 1997-06-25 Philips Electronique Grand Public Cable television distribution system
US5760822A (en) 1996-01-30 1998-06-02 Lucent Technologies Inc. Central node converter for local network having single coaxial cable
US5959592A (en) 1996-03-18 1999-09-28 Echostar Engineering Corporation "IF" bandstacked low noise block converter combined with diplexer
US5838740A (en) 1996-04-17 1998-11-17 Motorola, Inc. Crosspole interference canceling receiver for signals with unrelated baud rates
US5790202A (en) 1996-05-15 1998-08-04 Echostar Communications Corporation Integration of off-air and satellite TV tuners in a direct broadcast system
US5734356A (en) 1996-06-07 1998-03-31 Rf-Link Systems, Inc. Construction for portable disk antenna
JPH1051343A (en) 1996-08-06 1998-02-20 Fujitsu Ltd Signal receiver and signal reception system
US5760819A (en) 1996-06-19 1998-06-02 Hughes Electronics Distribution of a large number of live television programs to individual passengers in an aircraft
US5886995A (en) 1996-09-05 1999-03-23 Hughes Electronics Corporation Dynamic mapping of broadcast resources
US5848239A (en) * 1996-09-30 1998-12-08 Victory Company Of Japan, Ltd. Variable-speed communication and reproduction system
JPH10135858A (en) 1996-11-01 1998-05-22 Maspro Denkoh Corp Satellite signal distributer
US5787335A (en) 1996-11-18 1998-07-28 Ethnic-American Broadcasting Co, Lp Direct broadcast satellite system for multiple dwelling units
US5835128A (en) 1996-11-27 1998-11-10 Hughes Electronics Corporation Wireless redistribution of television signals in a multiple dwelling unit
WO1998026593A1 (en) 1996-12-12 1998-06-18 Rockwell Semiconductor Systems, Inc. Digital video converter box for subscriber/home with multiple television sets
US5970386A (en) 1997-01-27 1999-10-19 Hughes Electronics Corporation Transmodulated broadcast delivery system for use in multiple dwelling units
US5905942A (en) 1997-02-18 1999-05-18 Lodgenet Entertainment Corporation Multiple dwelling unit interactive audio/video distribution system
US6104908A (en) 1997-02-28 2000-08-15 Hughes Electronics Corporation System for and method of combining signals of combining signals of diverse modulation formats for distribution in multiple dwelling units
US5923288A (en) 1997-03-25 1999-07-13 Sony Coporation Antenna alignment indicator system for satellite receiver
CA2401726C (en) 1997-06-25 2010-10-19 Richard James Humpleman Browser based command and control home network
US6192399B1 (en) 1997-07-11 2001-02-20 Inline Connections Corporation Twisted pair communication system
TW420952B (en) 1997-08-26 2001-02-01 Eagle Comtronics Inc Sync suppression television security system with addressable sync restoration
FR2768001A1 (en) 1997-08-27 1999-02-26 Philips Electronics Nv CABLE DISTRIBUTION DEVICE FOR TELEVISION SIGNALS
US5982333A (en) 1997-09-03 1999-11-09 Qualcomm Incorporated Steerable antenna system
US5898455A (en) 1997-12-23 1999-04-27 California Amplifier, Inc. Interface modules and methods for coupling combined communication signals to communication receivers
US6510152B1 (en) 1997-12-31 2003-01-21 At&T Corp. Coaxial cable/twisted pair fed, integrated residence gateway controlled, set-top box
AU2760599A (en) 1998-02-04 1999-08-23 Friedman, Robert F. Method and apparatus for combining transponders on multiple satellites into virtual channels
US6424817B1 (en) 1998-02-04 2002-07-23 California Amplifier, Inc. Dual-polarity low-noise block downconverter systems and methods
US6202211B1 (en) 1998-02-06 2001-03-13 Henry R. Williams, Jr. Method and apparatus for providing television signals to multiple viewing systems on a network
US8284774B2 (en) 1998-04-03 2012-10-09 Megawave Audio Llc Ethernet digital storage (EDS) card and satellite transmission system
US20050204388A1 (en) 1998-06-11 2005-09-15 Knudson Edward B. Series reminders and series recording from an interactive television program guide
JP2995177B1 (en) * 1998-07-10 1999-12-27 株式会社ディジタル・ビジョン・ラボラトリーズ Stream distribution system
CN1867068A (en) 1998-07-14 2006-11-22 联合视频制品公司 Client-server based interactive television program guide system with remote server recording
US6038425A (en) 1998-08-03 2000-03-14 Jeffrey; Ross A. Audio/video signal redistribution system
US6304618B1 (en) 1998-08-31 2001-10-16 Ericsson Inc. Methods and systems for reducing co-channel interference using multiple timings for a received signal
US6598231B1 (en) 1998-09-08 2003-07-22 Asvan Technology, Llc Enhanced security communications system
WO2000028712A2 (en) 1998-10-30 2000-05-18 Broadcom Corporation Cable modem system
US6442148B1 (en) 1998-12-23 2002-08-27 Hughes Electronics Corporation Reconfigurable multibeam communications satellite having frequency channelization
US6452991B1 (en) 1998-12-30 2002-09-17 Ericsson Inc. Systems and methods for acquiring channel synchronization in time division multiple access communications systems using dual detection thresholds
JP3562985B2 (en) 1999-01-27 2004-09-08 アルプス電気株式会社 Converter for satellite broadcasting reception
AU3486900A (en) 1999-02-22 2000-09-14 Terk Technologies Corp. Video transmission system and method utilizing phone lines in multiple unit dwellings
US8191166B2 (en) * 2002-09-27 2012-05-29 Broadcom Corporation System and method for securely handling control information
US7127734B1 (en) 1999-04-12 2006-10-24 Texas Instruments Incorporated System and methods for home network communications
US6986156B1 (en) * 1999-06-11 2006-01-10 Scientific Atlanta, Inc Systems and methods for adaptive scheduling and dynamic bandwidth resource allocation management in a digital broadband delivery system
US6188372B1 (en) 1999-06-17 2001-02-13 Channel Master Llc Antenna with molded integral polarity plate
US6944878B1 (en) 1999-07-19 2005-09-13 Thomson Licensing S.A. Method and apparatus for selecting a satellite signal
US6574235B1 (en) 1999-08-12 2003-06-03 Ericsson Inc. Methods of receiving co-channel signals by channel separation and successive cancellation and related receivers
US6430233B1 (en) 1999-08-30 2002-08-06 Hughes Electronics Corporation Single-LNB satellite data receiver
US7110434B2 (en) 1999-08-31 2006-09-19 Broadcom Corporation Cancellation of interference in a communication system with application to S-CDMA
US7069574B1 (en) 1999-09-02 2006-06-27 Broadlogic Network Technologies, Inc. System time clock capture for computer satellite receiver
JP3600765B2 (en) 1999-10-29 2004-12-15 シャープ株式会社 Receiver
US6340956B1 (en) 1999-11-12 2002-01-22 Leland H. Bowen Collapsible impulse radiating antenna
US6889385B1 (en) 2000-01-14 2005-05-03 Terayon Communication Systems, Inc Home network for receiving video-on-demand and other requested programs and services
US6799208B1 (en) 2000-05-02 2004-09-28 Microsoft Corporation Resource manager architecture
EP1295410B1 (en) 2000-06-15 2004-10-06 Spacenet, Inc. System and method for satellite based controlled aloha
US20020044614A1 (en) 2000-09-12 2002-04-18 Molnar Karl James Methods and systems for reducing interference using co-channel interference mapping
US6441797B1 (en) 2000-09-29 2002-08-27 Hughes Electronics Corporation Aggregated distribution of multiple satellite transponder signals from a satellite dish antenna
US20020083574A1 (en) 2000-12-29 2002-07-04 Matz William R. Method for aligning an antenna with a satellite
US7012957B2 (en) * 2001-02-01 2006-03-14 Broadcom Corporation High performance equalizer having reduced complexity
US20020152467A1 (en) 2001-02-12 2002-10-17 Rosario Fiallos Automated generation of conditional access packets for IRD upgrades via radio frequency software download in satellite television systems
US20020178454A1 (en) 2001-02-14 2002-11-28 Antoine Mark J. Broadcast television and satellite signal switching system and method for telephony signal insertion
US7050419B2 (en) 2001-02-23 2006-05-23 Terayon Communicaion Systems, Inc. Head end receiver for digital data delivery systems using mixed mode SCDMA and TDMA multiplexing
US6512485B2 (en) 2001-03-12 2003-01-28 Wildblue Communications, Inc. Multi-band antenna for bundled broadband satellite internet access and DBS television service
KR20020078359A (en) 2001-04-09 2002-10-18 한국디지털위성방송(주) Electronic Commerce System and Method by Digital Broadcasting
US7486722B2 (en) 2001-04-18 2009-02-03 Bae Systems Information And Electronic Systems Integration Inc. Bandwidth efficient cable network modem
US20020154055A1 (en) 2001-04-18 2002-10-24 Robert Davis LAN based satellite antenna/satellite multiswitch
US7209524B2 (en) 2001-04-27 2007-04-24 The Directv Group, Inc. Layered modulation for digital signals
US7245671B1 (en) * 2001-04-27 2007-07-17 The Directv Group, Inc. Preprocessing signal layers in a layered modulation digital signal system to use legacy receivers
US7184473B2 (en) 2001-04-27 2007-02-27 The Directv Group, Inc. Equalizers for layered modulated and other signals
US8291457B2 (en) 2001-05-24 2012-10-16 Vixs Systems, Inc. Channel selection in a multimedia system
DE60128152D1 (en) 2001-06-19 2007-06-06 Stratos Wireless Inc DIPLEXER SWITCHING / CIRCUIT WITH MODEM FUNCTION
US6983312B1 (en) 2001-07-16 2006-01-03 At&T Corp. Method for using scheduled hyperlinks to record multimedia content
US20030016166A1 (en) * 2001-07-18 2003-01-23 Fastlocation.Net, Llc Method and system for processing positioning signals with matching assistance
US20030023978A1 (en) 2001-07-25 2003-01-30 Bajgrowicz Brian David Satellite television system
US7382838B2 (en) * 2001-09-17 2008-06-03 Digeo, Inc. Frequency drift compensation across multiple broadband signals in a digital receiver system
US6879301B2 (en) 2001-10-09 2005-04-12 Tyco Electronics Corporation Apparatus and articles of manufacture for an automotive antenna mounting gasket
US6762727B2 (en) 2001-10-09 2004-07-13 Tyco Electronics Corporation Quick-attach, single-sided automotive antenna attachment assembly
US7085529B1 (en) 2001-10-24 2006-08-01 The Directv Group, Inc. Method and apparatus for determining a direct-to-home satellite receiver multi-switch type
US6653981B2 (en) 2001-11-01 2003-11-25 Tia Mobile, Inc. Easy set-up, low profile, vehicle mounted, satellite antenna
US7130576B1 (en) * 2001-11-07 2006-10-31 Entropic Communications, Inc. Signal selector and combiner for broadband content distribution
US7257638B2 (en) 2001-12-20 2007-08-14 Microsoft Corporation Distributing network applications
ES2271385T3 (en) 2001-12-21 2007-04-16 Thomson Licensing MULTIPLE SIGNAL SWITCHING DEVICE.
WO2003058967A1 (en) 2001-12-28 2003-07-17 Pegasus Development Corporation Wideband direct-to-home broadcasting satellite communications system and method
JP2003204278A (en) 2002-01-07 2003-07-18 Sharp Corp Converter for satellite broadcasting reception
US20090222875A1 (en) * 2002-04-18 2009-09-03 Cheng David J Distributed tuner allocation and conflict resolution
US7010265B2 (en) 2002-05-22 2006-03-07 Microsoft Corporation Satellite receiving system with transmodulating outdoor unit
US7072627B2 (en) 2002-06-27 2006-07-04 Microsoft Corporation Method and apparatus for adjusting signal component strength
CN1413021A (en) 2002-08-27 2003-04-23 强海胜 Multi-edition TV program satellite broadcast/automatic receiving, editing and recording transmission method
US7039169B2 (en) 2002-09-25 2006-05-02 Lsi Logic Corporation Detection and authentication of multiple integrated receiver decoders (IRDs) within a subscriber dwelling
US7954127B2 (en) 2002-09-25 2011-05-31 The Directv Group, Inc. Direct broadcast signal distribution methods
US7216283B2 (en) 2003-06-13 2007-05-08 Broadcom Corporation Iterative metric updating when decoding LDPC (low density parity check) coded signals and LDPC coded modulation signals
US20040136455A1 (en) 2002-10-29 2004-07-15 Akhter Mohammad Shahanshah Efficient bit stream synchronization
AU2003293542A1 (en) * 2002-12-11 2004-06-30 R.F. Magic, Inc. Nxm crosspoint switch with band translation
WO2004054143A1 (en) 2002-12-12 2004-06-24 Oasis Silicon Systems Ag Distribution system for satellite broadcasts
US7016643B1 (en) * 2003-01-10 2006-03-21 The Directv Group, Inc. Antenna positioning system and method for simultaneous reception of signals from a plurality of satellites
US20040153942A1 (en) 2003-01-24 2004-08-05 Nathan Shtutman Soft input soft output decoder for turbo codes
US7242910B2 (en) * 2003-02-03 2007-07-10 M/A-Com, Inc. Self-calibrating radio
US7751477B2 (en) 2003-02-13 2010-07-06 Broadcom Corporation Communications signal transcoder
JP4368592B2 (en) 2003-02-19 2009-11-18 シャープ株式会社 Digital broadcast receiving tuner and receiving apparatus having the same
JP2004312668A (en) 2003-03-25 2004-11-04 Sharp Corp Low-noise converter
US20040244059A1 (en) 2003-05-30 2004-12-02 Lsi Logic Corporation Digital set-top box transmodulator
US20040261110A1 (en) 2003-06-23 2004-12-23 Lodgenet Entertainment Corporation Lodging entertainment system with guest controlled integrated receiver decoder
US7623580B2 (en) 2003-06-30 2009-11-24 Nxp B.V. Simultaneous multiple channel receiver
US7848303B2 (en) 2003-06-30 2010-12-07 Nxp B.V. Satellite multi-choice switch system
US7603022B2 (en) 2003-07-02 2009-10-13 Macrovision Corporation Networked personal video recording system
TWI257732B (en) 2003-09-10 2006-07-01 Wistron Neweb Corp Antenna carrier which allows minor adjustments of its orientation angle
JP4170863B2 (en) 2003-09-11 2008-10-22 Dxアンテナ株式会社 Dish antenna rotating device
US7200745B2 (en) 2003-09-12 2007-04-03 Microsoft Corporation System and method for specifying and utilizing hardware functionality by executing a common hardware register pseudo-language
US20050066367A1 (en) 2003-09-19 2005-03-24 Fyke Gregory James Integrated receiver decoder for receiving digitally modulated signals from a satellite
US20050198673A1 (en) 2003-11-03 2005-09-08 John Kit Satellite TV security system
JP2005159779A (en) 2003-11-27 2005-06-16 Hitachi Ltd Receiver, display apparatus, and recording apparatus
US20050138663A1 (en) 2003-12-19 2005-06-23 Throckmorton John A. Distributed video recording and playback
FR2866767A1 (en) 2004-02-23 2005-08-26 Thomson METHOD OF COMMUNICATION BETWEEN DOMESTIC APPLIANCES AND APPARATUSES IMPLEMENTING THE METHOD
JP4214399B2 (en) 2004-02-23 2009-01-28 ミツミ電機株式会社 Fixing structure using a pair of screw parts and antenna device using the same
US7239285B2 (en) 2004-05-18 2007-07-03 Probrand International, Inc. Circular polarity elliptical horn antenna
KR100550905B1 (en) 2004-06-28 2006-02-13 삼성전기주식회사 Intelligent LOW NOISE BLOCKDOWN CONVERTER
US7712120B2 (en) 2004-07-26 2010-05-04 At&T Intellectual Property I, L.P. System and method for distributing DBS content to multiple receivers in the home over a single coax
US20060041912A1 (en) 2004-08-19 2006-02-23 Kevin Kuhns Method and apparatus for authorizing an additional set-top device in a satellite television network
US7743406B2 (en) 2004-12-21 2010-06-22 International Business Machines Corporation System and method of preventing alteration of data on a wireless device
US7522875B1 (en) * 2004-12-31 2009-04-21 Entropic Communications Inc. Signal selector and combiner system for broadband content distribution
US20060174282A1 (en) 2005-01-31 2006-08-03 Pro Brand International, Inc. Bi-directional signal coupler
US8549565B2 (en) 2005-04-01 2013-10-01 The Directv Group, Inc. Power balancing signal combiner
US7958531B2 (en) 2005-04-01 2011-06-07 The Directv Group, Inc. Automatic level control for incoming signals of different signal strengths
US7716662B2 (en) * 2005-06-22 2010-05-11 Comcast Cable Holdings, Llc System and method for generating a set top box code download step sequence
GB2428949B (en) * 2005-07-28 2007-11-14 Artimi Inc Communications systems and methods
US8019275B2 (en) 2005-10-12 2011-09-13 The Directv Group, Inc. Band upconverter approach to KA/KU signal distribution
US7634250B1 (en) 2006-03-17 2009-12-15 Sprint Spectrum L.P. Signal conditioner and method for communicating over a shared transport medium a combined digital signal for wireless service
US7697911B2 (en) * 2006-12-08 2010-04-13 Agere Systems Inc. Single path architecture with digital automatic gain control for SDARS receivers
US7929915B2 (en) * 2007-09-28 2011-04-19 Verizon Patent And Licensing Inc. Method and system for measuring cross-polarization isolation value and 1 dB gain compression point
US8379823B2 (en) * 2008-04-07 2013-02-19 Polycom, Inc. Distributed bridging
US20100169934A1 (en) * 2008-12-26 2010-07-01 Dish Network L.L.C. Systems and methods for determining user position via wireless signal characteristics

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6173164B1 (en) * 1997-09-15 2001-01-09 Wireless Access Method and apparatus for wide range automatic frequency control
GB2354650A (en) * 1999-06-25 2001-03-28 Nec Corp Automatic frequency control circuit
US6463266B1 (en) * 1999-08-10 2002-10-08 Broadcom Corporation Radio frequency control for communications systems
US20080064355A1 (en) * 2006-09-13 2008-03-13 Ilan Sutskover Method and apparatus for efficiently applying frequency correction

Also Published As

Publication number Publication date
US9203536B2 (en) 2015-12-01
US20100172446A1 (en) 2010-07-08
BRPI1006912A2 (en) 2016-02-16
US8509722B2 (en) 2013-08-13
US8229383B2 (en) 2012-07-24
US20120281745A1 (en) 2012-11-08
MX2011007027A (en) 2011-07-20
US20130331025A1 (en) 2013-12-12
AR074992A1 (en) 2011-03-02

Similar Documents

Publication Publication Date Title
US9203536B2 (en) Frequency drift estimation for low cost outdoor unit frequency conversions and system diagnostics
US8611809B1 (en) Computationally efficient design for broadcast satellite single wire and/or direct demod interface
US9565012B2 (en) Systems and methods for selecting digital content channels using low noise block converters including digital channelizer switches
US9407369B2 (en) Optical converter with ADC based channelizer for optical LNB system
US20030163822A1 (en) Satellite television system ground station having wideband multi-channel LNB converter/transmitter architecture with coarse tuner in outdoor unit
US8418210B2 (en) Satellite television system ground station having wideband multi-channel LNB converter/transmitter architecture with controlled uplink transmission
US20030163820A1 (en) Satellite television system ground station having wideband multi-channel LNB converter/transmitter architecture utilizing a frequency stabilized common oscillator
US10256898B2 (en) Method and system for guard band detection and frequency offset detection
US8712318B2 (en) Integrated multi-sat LNB and frequency translation module
US20200036384A1 (en) Detection and compensation of dielectric resonator oscillator frequency drift
US20160127122A1 (en) Quadricorrelator carrier frequency tracking
US20180288475A9 (en) Flexible channel stacking
US9985666B2 (en) Transmission device, reception device, broadcast signal processing method, and broadcast receiver
JP2002199389A (en) Down converter, up converter and catv system
US20070288968A1 (en) Video and data home networking architectures

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 10700898

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: MX/A/2011/007027

Country of ref document: MX

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10700898

Country of ref document: EP

Kind code of ref document: A1

REG Reference to national code

Ref country code: BR

Ref legal event code: B01A

Ref document number: PI1006912

Country of ref document: BR

ENP Entry into the national phase

Ref document number: PI1006912

Country of ref document: BR

Kind code of ref document: A2

Effective date: 20110705