INTEGRATED CIRCUIT CARD FOR
FIELD OF THE INVENTION
The present invention relates to communication systems in general, and in particular to computer communication systems.
BACKGROUND OF THE INVENTION
Despite the fact that a majority of individuals in the United States have access to one or more personal computers, most residences are not wired to take advantage of the high-speed communication or resource sharing capabilities of such computers. Most computer-to-computer or computer-to-peripheral communications take place over high-speed networking cables not found in most residences. As an alternative to rewiring existing homes with high-speed cables such as Ethernet, a standardized high-speed data transfer protocol called Home PNA is jointly being developed by companies such as 3Com, AMD, ATT, Compaq, Conexant, IBM, Intel, and Lucent. Home PNA allows computer systems to transmit and receive high-speed digital data over the existing telephone wires which are generally routed throughout a residence. Home PNA signals are transmitted in a frequency band that extends from 5.5-9.5 MHz in order to avoid conflict with other signals, such as DSL or voice signals, that may be simultaneously transmitted on the telephone wiring.
In the past, if a user wanted to be able to transmit and receive data from their computer, the computer had to be equipped with multiple interface cards. One card may be an analog modem for transmitting and receiving data in the voice band of a conventional telephone circuit. A DSL card is required to transmit and receive high-speed digital data on a set of telephone wires. Finally, to transmit and receive data on a Home PNA network, yet another interface card is required. Each of these cards typically includes an arrangement of niters that isolate data signals in a particular frequency band. The niters are primarily comprised of a number of analog components that are expensive to manufacture and align. To reduce the redundancy associated with having more than one individual interface card, there is a need for a single interface card that can facilitate transmitting and receiving digital data in a number of different frequency bands without the need for complex analog filter components.
SUMMARY OF THE INVENTION
The present invention is a single interface card that allows a computer to transmit and receive digital data in a number of frequency bands without the use of analog filter components. To transmit and receive data on conventional household telephone wiring, the interface card includes an isolation circuit that couples signals from the telephone wiring to the interface card. The output of the isolation circuit feeds a single analog-to-digital/digital-to-analog (AtoD/DtoA) converter. The output of the AtoD/DtoA converter feeds a digital splitter/combiner that utilizes digital signal processing or discrete digital logic to filter digital data into multiple frequency domains. Signals in a voice band from 0.1-4 kHz are supplied by the digital splitter/combiner to a PCM modem. Signals in the 85-500 kHz range are supplied to DSL circuitry. In addition, digital signals in the 5.5-9.5 MHz range are supplied by the digital splitter/combiner to Home PNA circuitry. The digital splitter/combiner allows a single
card to be created with few or no analog filter components, as well as eliminates the need for multiple separate integrated circuits for processing each of the different frequency bands.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the
following detailed description, when taken in conjunction
with the accompanying drawings, wherein:
FIG. 1 illustrates a conventional method of providing
high-speed data to a residence wired with a cable modem; 15 FIG. 2 illustrates the multiple interface cards required to
allow a computer to transmit and receive DSL and Home
PNA signals over existing telephone wiring; and
FIG. 3 illustrates an interface card that allows a computer
to transmit and receive digital data in a conventional tele20 phone voice band, DSL frequency or Home PNA frequency
band according to the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
As indicated above, the present invention is an interface card for allowing a computer system to receive high-speed digital data from conventional telephone wiring without unnecessary and bulky analog filter components.
FIG. 1 illustrates one conventional method of delivering
3Q high-speed digital data and telephone signals to a residence. Telephone signals and digital data are supplied on a data carrying line 10 which typically comprises a hybrid fiber optic and coaxial cable. The cable terminates at a junction box 12 located at a residence 14. The junction box 12
35 includes a cable modem (not shown) that routes high-speed digital data over an Ethernet cable 16 to a computer system 18. In addition, the junction box 12 includes a telephone interface circuit (not shown) that powers a telephone 22 and generates the appropriate ringing signals, dial tone, etc. The
40 telephone interface circuit supplies the telephone signals on a conventional set of twisted telephone wires 20. As indicated above, one of the primary factors that inhibit the many computer users from receiving higher speed digital data is the fact that their house, apartment, townhouse, etc., is not
45 wired with the high-speed Ethernet cable 16. Therefore, these cables must be specially installed by an Internet service provider, cable operator, or other technician thereby increasing the expense associated with receiving higher speed digital data.
50 FIG. 2 illustrates another conventional method by which residences receive high-speed digital data. Many phone companies provide telephone signals and high-speed digital data on conventional twisted pair telephone lines using digital subscriber line (DSL) technology. The DSL data
55 signals are typically transmitted in a frequency band which is separated from the frequency band occupied by the telephone voice signals so that the digital data can be separated from the voice data and supplied to a computer system. The advantage of DSL networks is that the data can
go be routed throughout a residence using the existing telephone wiring.
In order to provide networking capabilities to home users without the installation of dedicated networking cables, a new technology called Home PNA, which was developed by 65 various companies including 3Com, AMD, ATT, Compaq, Conexant, IBM, Intel, and Lucent, allows data to be transmitted between computers or between computers and