|Publication number||US20070154184 A1|
|Application number||US 11/724,177|
|Publication date||Jul 5, 2007|
|Filing date||Mar 15, 2007|
|Priority date||Sep 9, 1997|
|Also published as||US6397000, US6920279, US7197229, US20020141736, US20050185934|
|Publication number||11724177, 724177, US 2007/0154184 A1, US 2007/154184 A1, US 20070154184 A1, US 20070154184A1, US 2007154184 A1, US 2007154184A1, US-A1-20070154184, US-A1-2007154184, US2007/0154184A1, US2007/154184A1, US20070154184 A1, US20070154184A1, US2007154184 A1, US2007154184A1|
|Inventors||Yuji Hatanaka, Hiroo Okamoto|
|Original Assignee||Yuji Hatanaka, Hiroo Okamoto|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (7), Classifications (18)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This is a continuation of U.S. application Ser. No. 11/110,691, filed Apr. 21, 2005, which is a continuation of U.S. application Ser. No. 10/154,958, filed May 28, 2002 (now U.S. Pat. No. 6,920,279), which is a continuation of U.S. application Ser. No. 09/090,919, filed Jun. 5, 1998 (now U.S. Pat. No. 6,397,000). This application relates to and claims priority from Japanese Patent Application No. 09-243667, filed on Sep. 9, 1997. The entirety of the contents and subject matter of all of the above is incorporated herein by reference.
The present invention relates to digital signal recording devices, digital signal recording/playback devices, and digital signal receiving/recording/playback devices, for receiving/recording/playing back a digital signal.
JP-A-8-98164 discloses a receiving system and a recording/playing back device for receiving/recording a transmitted multiplexed digital signal as a conventional technique for recording/playing back a digital signal. This prior art publication describes a receiving system which includes receiving means for receiving a transmitted multiplexed digital information signal and for selecting desired information, and recording means for recording the information received by the receiving means.
This prior art system is capable of recording/playing back an incoming digital signal as it is, but it cannot convert an analog television signal like terrestrial broadcasting waves used at present to a digital signal, and record/play back the digital signal.
It is therefore an object of the present invention to provide a digital signal receiving device, a digital signal recording/playing back device and a digital signal receiving/recording/playing back device, having the functions of converting an analog television signal to a digital signal, and recording/playing back the digital signal in a digital signal receiving/recording/playing back system.
According to one aspect of the present invention, there is provided a digital signal recording device comprising:
Embodiments of the present invention will be described next with reference to the accompanying drawings.
A digital broadcasting signal sent from a satellite is received at the digital broadcasting signal input terminal 4, and inputted to the tuner 5 which selects and outputs a desired signal. The output from the tuner 5 is demodulated by the QPSK demodulator 6 and then inputted to the FEC 7, which corrects an error involved in the received digital signal in the transmission. The output from the FEC 7 is delivered to the playback changeover switch 8 and the interface 12.
When the broadcasting signal is outputted from the present device, the playback changeover switch 8 is set at a contact a to input the output from the FEC 7 to demultiplexer 9, which determines a type of a respective packet, using the PID 57, etc., of the header 50, separates only packets of a video, audio, etc., relating to a specified program, and then outputs these packets to the MPEG decoder 10. The multiplexed signal contains a packet called, for example, a PCR (Program Clock Reference) indicative of time information representing the time when compression took place in a broadcasting station concerned. Thus, the clock recovery unit 13 reproduces a data clock 45 using this PCR. The decoder clock 45 reproduced by the clock recovery unit 13 is controlled so as to have the same frequency as a clock used in a compressor (not shown) which compresses video and audio data information in accordance with the MPEG 2 in the broadcasting station. The MPEG decoder 10 expands the respective video and audio signals compressed in accordance with the MPEG 2, etc., by using the received separating signal and the data clock 45 reproduced by the clock reproducing unit 13, and provides decoded video/audio signals. The video signal is converted by the NTSC encoder 11 to a television analog video signal, which is then output from the video output terminal 15. The audio signal is converted by the D/A converter 14 to an analog audio signal, which is then outputted from the audio output terminal 16.
When the received signal is recorded in the recording/playback device 2, the output from the FEC 7 is inputted to the interface 12, which separates packets of video and audio information and added information relating to a program to be recorded as in the demultiplexer 9. When the received signal is recorded and played back by the recording/playback device 2, it is required to record even program information required for automatic selection of a broadcasting station. Thus, in addition to the packet selected by the demultiplexer 9, the interface 12 also selects information on another program and also converts a part of the packet. The signal separated by the interface 12 is inputted to the packet control circuit 18 by selecting a contact c by the recording signal changeover switch 17. As shown in main data of
As shown in
In reproduction, a signal 153 reproduced by the rotary head 23 is inputted via the playback amplifier 21 to the recording/playback circuit 19, which detects the sync signal 92, signals ID1 (93), ID2 (94), etc., and corrects errors, using the C1P101, C2P76, etc., extracts packet data A 99 and B 100 and then sends those data to the packet control circuit 18. The packet control circuit 18 outputs the respective packets at the same intervals of time as in the recording, in accordance with the time stamp 102 added when the data is recorded, and then sent via the interface 12 to the playback changeover switch 8. When a reproduced picture is to be obtained, the playback changeover switch 8 is set at the contact b to thereby send a reproduced packet to the demultiplexer 9. The demultiplexer 9 automatically selects a broadcasting station on the basis of a packet on program information separated and converted by the interface 12 when the data is recorded, and outputs only a packet required for the MPEG decoder 10. Video/audio signals are obtained in a manner similar to that in which an output is obtained from a broadcasting signal.
Also, in playback, the data clock 45 used in the MPEG decoder 10 is required to obtain the same frequency as it was compressed in the broadcasting station. To this end, at least the respective PCR time intervals inputted when recorded are required to be maintained, reproduced and outputted correctly. To this end, in recording, the time stamp 102 is added in the packet control circuit 18. In playback, the respective packets are outputted by the packet control circuit 18 in accordance with the time stamps 102 to maintain the time intervals at which the packets are outputted. To this end, clocks used for producing the time stamp 102 in the recording should be decoder clock 45 reproduced by the clock recovery unit 13. In recording, the clock changeover switch 25 is set at a contact e so that the decoder clock 45 is inputted to the packet control circuit 18.
In reproduction, the clock recovery unit 13 of the digital broadcasting receiver 1 is operated by a timing signal outputted from the packet control circuit 18 to produce decoder clock 45. Thus, the packet control circuit 18 cannot use the decoder clock 45. In order to avoid this, the clock generator 24 which generates a fixed clock 46 is provided so that when the clock changeover switch 25 is set at a contact f, the fixed clock 46 is inputted to the packet control circuit 18 and a packet is outputted at a timing generated by the fixed clock 46. Thus, the clock recovery unit 13 is able to generate a stabilized clock depending on the fixed clock 46. The clock generator 24 generally uses a crystal oscillator. In this case, the frequency of the crystal oscillator should be within the standards of MPEG 2, etc.
Recording/playback of an analog broadcasting such as a terrestrial broadcasting performed at present in the present recording/playback device will be described next.
When the analog broadcasting signal is recorded, an analog video signal 150 is inputted to the video input terminal 26 of the encoder 3 of
As shown in
Reference symbols NULs 115, 125 and 126 denote senseless dummy data whose quantities are each dependent on the difference between the total number of packets and the transmission rate of the multiplexed stream.
As shown in
Thus, the multiplexed stream 44 has a stream composition similar to the output of the interface 12 of the digital broadcasting receiver 1. Thus, the recording signal changeover switch 17 selects a contact d and inputs the multiplexed stream 44 to the packet control circuit 18 to thereby record/playback the multiplexed stream 44 in the same manner as the digital broadcasting signal.
When the multiplexed stream 44 is recorded, the clock frequency used for producing the time stamp 102 in the packet control circuit 18 is required to have the same frequency as the clock used in the video and audio encoders 30 and 31, as described with respect to the recording of the digital broadcasting. Thus, as shown in
When there is a margin in the transfer rate given to the recording/playback device, the digital and analog broadcasting signals are recordable simultaneously.
In recording, as shown in
In this case, the packet control circuit 18 uses the data clock 45 produced by the clock recovery unit 13. Thus, the clock changeover switch is set at a contact e, and the video and audio encoders 30 and 31 also use the decoder clock 45. In playback, the clock changeover switch 25 is set at a contact f to use the fixed clock 46.
In playback, the user selects one of the digital and analog broadcasts, the demultiplexer 9 selects only one of the digital and analog broadcasts on the basis of the PAT converted in the recording, and inputs the selected program packet to the MPEG decoder 10 to obtain the video and audio of the desired program.
Thus, the digital broadcasting signal and the digital signal to which the analog broadcasting signal is converted are easily recorded simultaneously in a multichannel. If the video and audio streams 42 and 43 alone are multiplexed in a mode in which no broadcasting stream 41 is outputted in the multiplexer 32 of the
While in the above the interface 12, multiplexer 32 and packet control circuit 18 are described as handling a one-way signal, these elements may be replaced with an input/output bus.
In the arrangement of
The video A/D converter 28, audio A/D converter 29, video encoder 30, audio encoder 31 and multiplexer 32 may be built either in the recording/playback device 2 or in the digital broadcasting receiver 1. Although not shown, the demultiplexer 9, MPEG decoder 10, NTSC encoder 11, and D/A converter 14 may also be provided in the recording/playback device 2 as well. Thus, even the recording/playback device is capable of providing a reproduced video signal by itself. Of course, the digital broadcasting receiver 1, recording/playback device 2 and encoder 3 may be all integrated in one unit.
While in the above description the recording/playback of a digital signal alone has been described, the present device may have the function of recording/reproducing an analog signal as in a VHS and a VTR available at present.
When a digital signal is recorded in the device of
When the analog broadcasting signal is digitally recorded, this signal is received at the analog broadcasting signal input terminal 200, and inputted to the analog tuner 201 to produce analog video and audio signals 150 and 151 of a desired program, which are then inputted to the encoder 3.
When the analog broadcasting signal is analog-recorded using a VHS system available at present, the analog broadcasting signal is similarly received at the analog broadcasting signal input terminal 200, and then inputted to the analog tuner 201 to produce analog video and audio signals 150 and 151 of the desired program. The analog video signal 150 is processed by the analog video recording/playback circuit 203 so as to be a signal, for example, conforming to VHS standards, which signal is then recorded via the analog video record amplifier 204 by the video head 220 of the rotary head 23. Simultaneously, the analog signal 151 is produced by the analog audio recording/playback circuit 202 so as to be a signal, for example, conforming to the VHS standards, and then recorded via the digital recording changeover switch 210 set at a contact h and the record amplifier 20 by the audio head 221 of the rotary head 23. A servo tracking signal is recorded as in the digital recording. The video and audio heads 220 and 221 are different in azimuth angle and azimuth-record the video and audio signals.
Because of an azimuth loss in reproduction, the signal recorded by the video head 220 is reproduced by the video head 220 alone while the signal recorded by the audio head 221 is reproduced by the audio head 221 alone. The video signal reproduced by the video head 220 is reproduced via the analog video playback amplifier 205 by the analog video recording/playback processing circuit 203 to produce a reproduced video signal 232, which is then outputted via the output selector 207 from the external video terminal 209. The audio signal reproduced by the audio head 221 is processed by the analog audio recording/playback processing circuit 202 via the reproduction amplifier 21 to produce a reproduced audio signal 233, which is then outputted via the output selector 207 from the external audio terminal 208.
In this case, generally, the digital recording is different in the feeding speed of the magnetic tape 22 from the analog recording. The system controller 206 controls the mode so that for example, a standard mode (SP mode) or a triple mode (EP mode) in the VHS standards is used in the analog recording while a double mode (LP mode) (½ of the tape feeding speed in the standard mode, i.e., the recording time is doubled) is used in the digital recording. In viem of the possibility that digital recording is performed only on a specified tape (for example, an S-VHS tape conforming to the VHS standards), so that the system controller 206 detects the type of a tape (generally, depending on the presence of holes in a cassette) and if the tape is different from the S-VHS tape, the system controller 206 always performs an analog recording operation.
In this case, the digital broadcasting signal cannot be digitally recorded as it is so that as shown in
In playing back, the system controller 206 detects a servo tracking signal to determine the tape speed in the recording operation and automatically selects analog playback in the standard and triple modes and digital playback in the double mode. Thus, the user is not required to pay attention to whether the broadcasting signal is digital-recorded or analog-recorded. The mode is automatically changed to a predetermined mode to thereby provide desired signals from the external video and audio output terminals 209 and 208.
The digital broadcasting receiver 1 may be another device without the output selector 207 so that the output from the digital broadcasting signal receiver 1 may be independent of the outputs from the analog video and audio playback processing circuits 203 and 202.
While in the above the magnetic tape is used as a recording medium, a magnetic disk, optical disk, semiconductor memory or other recording medium may be used. Although not shown in
In the recording device, recording/playback device, and receiving/recording/playback device, for a digital broadcasting signal, according to the present invention, the analog television signal is converted to a digital signal, which is then recorded and reproduced. The digital broadcasting signal and the digital signal to which the analog televison signal is converted are recorded simultaneously in a multichannel.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US6397000 *||Jun 5, 1998||May 28, 2002||Hitachi, Ltd.||Digital signal recording devices, digital signal recording/ playback devices, and digital signal receiving/recording/playback devices|
|US6920279 *||May 28, 2002||Jul 19, 2005||Hitachi, Ltd.||Digital signal recording devices, digital signal recording/playback devices, and digital signal receiving/recording/playback devices|
|US7197229 *||Apr 21, 2005||Mar 27, 2007||Hitachi, Ltd.||Digital signal recording devices, digital signal recording/playback devices, and digital signal receiving/recording/playback devices|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7676141 *||Nov 14, 2003||Mar 9, 2010||Panasonic Corporation||Recording apparatus and recording method|
|US7689100 *||Aug 30, 2004||Mar 30, 2010||Hitachi, Ltd.||Digital signal recording/reproducing apparatus|
|US7848365 *||Jun 13, 2006||Dec 7, 2010||Electronics And Telecommunications Research Institute||Apparatus for receiving cable TV broadcasting program, and multiplexer and de-multiplexer thereof|
|US8634026 *||Sep 3, 2008||Jan 21, 2014||Sony Corporation||Digital broadcast receiving apparatus|
|US20040136694 *||Nov 14, 2003||Jul 15, 2004||Shiro Iwasaki||Recording apparatus and recording method|
|US20050025458 *||Aug 30, 2004||Feb 3, 2005||Manabu Sasamoto||Digital signal recording/reproducing apparatus|
|US20090064239 *||Sep 3, 2008||Mar 5, 2009||Jiro Hara||Digital broadcast receiving apparatus|
|U.S. Classification||386/213, 386/E09.009, 386/E09.013, 386/328, 386/338, 386/327|
|International Classification||H04N5/92, G11B20/00, H04N5/928, H04N9/79, H04N9/804, G11B20/12, G11B20/10, H04N7/00|
|Cooperative Classification||H04N9/8042, H04N9/7921|
|European Classification||H04N9/804B, H04N9/79M|