JPH11177918A - Dtv signal recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the recording and reproducing device for a DTV signal with a simple configuration where complicated digital processing is avoided and an analog signal demodulated from a digital television TV signal is recorded directly on a tape recorder or reproduced. SOLUTION: A VSB signal from a receiver is given to a recording section. A synchronization timing signal detection circuit 14 detects a field synchronizing signal denoting a segment start position and a servo circuit 27A controls recording operation based on the field synchronizing signal. Information data for a segment block are recorded by FM or AM while keeping the analog value for one track block of a tape synchronously with the rotation of a rotary head. A time compression circuit 25 applies time compression to a signal fed from an RF signal amplifier 29A to the rotary head to prevent abnormity at changeover of rotary heads, and a demodulated analog signal is reproduced from the tape synchronously with a field synchronizing signal. Thus, the DTV signal is easily recorded or reproduced with a simple circuit configuration without complicated digital processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a DTV signal recording / reproducing apparatus for recording / reproducing a DTV signal.

[0002]

2. Description of the Related Art With the recent advance in digital television (DTV) broadcasting technology, the spread of image use in communication and package media has been moving toward a system having communication functions for television and package media reproduction functions. Time-shift viewing with a combination with a VCR (video cassette recorder) has also started to be performed.

[0003] A DTV signal transmission system has a configuration as shown in FIG. 7. Based on the MPEG system, a video signal is subjected to frame motion compensation, field motion compensation prediction, and high-efficiency motion compensation. Prediction (Dual-Prim
The digital compression based on e) is performed, and the DTV signal subjected to the digital compression based on the psychological auditory analysis is input to the data randomizer 1 for the audio signal, and the data is randomized. Then, the DTV transmission data subjected to the random processing is transmitted to the data randomizer 1.
In the Reed-Solomon encoder (RS encoder) 2 connected to the RS, an RS encoding process for using an RS code, which is a block code, for error correction is performed.

[0004] The DTV transmission data that has been subjected to the RS encoding process is converted into a random error by which a RS code can be corrected by a data interleaver 3 connected to a Reed-Solomon encoder 2. The connected trellis encoder 4 performs an error correction trellis encoding process.

[0005] In addition, D is trellis-encoded.
The TV transmission data and the segment synchronization signal and the field synchronization signal of the DTV transmission data are input to a multiplexer 5 connected to a trellis encoder 4, and the DTV transmission data is input to a pilot signal insertion circuit 6 connected to the multiplexer 5. , A pilot signal for reproducing a carrier wave at the time of reception is inserted, and then a pre-equalization filter 7 connected to a pilot signal insertion circuit 6 causes attenuation of each frequency in a transmission band and delay of a propagation time. Compensation is provided.

[0006] Then, the VSB modulator 8 connected to the pre-equalization filter 7 sets the DTV transmission data subjected to the equalization processing to a set of transmission data for every three bits.
VSB modulation for converting into one of eight types of amplitude values is performed, and transmitted as an RF signal from a transmitting antenna 10 by an RF upconverter 9 connected to the VSB modulator 8.

On the other hand, a DTV signal receiving system is shown in FIG.
The RF signal received by the receiving antenna 11 is tuned by the tuner 12 to the carrier frequency of the DTV received signal, and the intermediate frequency filter connected to the tuner 12 and the synchronous detection are used. The extraction of the intermediate frequency and the synchronous detection are performed by the device 13, and the DTV reception data including the error correction code, the segment synchronization signal, and the synchronization timing signal are extracted. Then, in the DTV reception data including the error correction code, the NTSC removal filter 15 connected to the intermediate frequency filter and the synchronous detector 13 removes the adjacent NTSC signal, and
An equalizer 16 connected to the TSC removal filter 15 performs attenuation for each frequency and compensation for a delay in propagation time.

Next, the DTV reception data is transmitted to the equalizer 16.
The phase synchronization circuit 17 connected to the phase synchronization circuit 17 synchronizes the phase, and the trellis decoder 1 connected to the phase synchronization circuit 17
At 8, a trellis decoding process is performed, and further, at the data deinterleaver 19 connected to the trellis decoder 18, the conversion of the DTV reception data, which has been converted into a random error that can correct the RS code, is canceled.

The received DTV data is supplied to a Reed-Solomon decoder 2 connected to a data deinterleaver 19.
0, an RS decoding process is performed, and the data de-randomizer 21 connected to the Reed-Solomon decoder 20 is processed.
In, the random processing of the data performed by the data randomizer 1 is canceled.

[0010] Further, the DTV reception data is input to a demultiplexer 22 connected to a data de-randomizer 21.
A signal is received.

An output terminal of the intermediate frequency filter and the synchronous detector 13 of the DTV signal receiving system is provided with an input / output terminal t1 of a VSB demodulated signal, and an output terminal of the data de-randomizer 21 is provided with an encoded MPEG system. And an input / output terminal t2 for DTV reception data compressed by.

Conventionally proposed DTV signal recording / reproduction for recording a DTV signal and reproducing the recorded DTV signal when the DTV signal transmitted by the transmission system is received by the reception system. The recording unit of the apparatus has a configuration as shown in FIG. 9, and the reproducing unit has a configuration as shown in FIG.

[0013] The recording unit includes a D-picture compressed by the MPEG system.
A packet circuit 34 for performing packet processing on the TV reception signal is provided. This packet circuit 34 includes a packet circuit 34 for making a single segment of a video segment, which is a unit of fixed length, uniform. Shuffling circuit 3 for performing data shuffling in which data is collected according to predetermined rules
5 is connected. The shuffling circuit 35 is connected to a RAM 33A for writing and reading data during a shuffling operation, and an RF signal amplifier 29A for amplifying an RF signal and supplying the amplified RF signal to the rotary head.

The reproducing section is provided with an RF signal amplifier 29B connected to the rotary head and amplifying the RF signal. The RF signal amplifier 29B is used to equalize the amount of information contained in the video segment. And a deshuffling circuit 37 for canceling the shuffling operation performed by the shuffling circuit 35 in which data is collected according to a predetermined rule from within one screen. The deshuffling circuit 37 includes a RAM 33B for writing and reading data during the deshuffling operation, and a packet circuit 3
4 is connected to a depacket circuit 36 for canceling the packet processing.

At the time of recording a DTV signal, FIG.
The input terminal of the packet circuit 34 of the recording unit of FIG. 9 is connected to the MPEG input / output terminal t2 of the receiving system of FIG. 9, and the packet circuit 34 performs packetization processing on the digitally compressed MPEG data. The shuffling circuit 35 equalizes the amount of information contained in a video segment, which is a unit of fixed length, from within one screen by a predetermined rule. Then, the DTV reception data in which the amount of information included in the video segment is equalized is amplified by the RF signal amplifier 29A and supplied to the rotary head, and the DTV reception data is recorded on the tape.

When the DTV signal recorded on the tape is reproduced, the DTV reception data read from the tape by the rotary head is amplified by the RF signal amplifier 29B, and the signal is amplified by the deshuffling circuit 37 and the shuffling circuit 35.
The processing of equalizing the amount of information included in the video segment performed in step (1) is released. Next, the packetizing process performed in the bucket circuit 34 is released by the depacket circuit 36, and the digitally compressed MPEG data is input to the MPEG input / output terminal t2 of the receiving system in FIG. This DTV reception data is transmitted via the demultiplexer 22 to the MP connected to the demultiplexer 22.
The video signal is decoded by the EG decoder 23 and connected to the receiving system, a video signal is displayed on a monitor, and an audio signal is reproduced by a speaker connected to the receiving system.

[0017]

SUMMARY OF THE INVENTION The aforementioned conventional DTV
In order to perform a recording operation in the recording unit of the signal recording / reproducing apparatus, a tuner 12 of the DTV signal receiving system shown in FIG.
It is necessary to connect the circuit configuration up to and the recording unit also requires digital processing such as packetization processing by the packet circuit 34 and shuffling processing by the shuffling circuit 35, which complicates the circuit configuration. . Similarly, the reproduction unit also requires digital processing such as cancellation of shuffling processing by the deshuffling circuit 37 and cancellation of packetization by the depacket circuit 36, and the circuit configuration becomes complicated.

The present invention has been made in view of the current state of recording / reproducing operation of a DTV signal as described above. An object of the present invention is to avoid complicated digital processing and to directly convert a demodulated analog signal of a DTV signal to a tape. An object of the present invention is to provide a DTV signal recording / reproducing apparatus which can be recorded and reproduced on a recorder and has a simple structure.

[0019]

In order to achieve the above object, according to the first aspect of the present invention, a DTV signal is recorded on a tape recorder having a rotary head, and the DTV signal recorded on the tape recorder is reproduced. A DTV signal recording / reproducing apparatus for detecting a field synchronization signal from a demodulated analog signal of a DTV signal; and rotating the rotary head in synchronization with the field synchronization signal to thereby obtain the demodulated analog signal. And a synchronous recording means for recording the demodulated analog signal from the running tape by rotating the rotary head in synchronization with the field synchronization signal. Synchronous playback means.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram illustrating a configuration of a DTV signal recording unit according to the present embodiment, FIG. 2 is a block diagram illustrating a configuration of a DTV signal reproducing unit according to the present embodiment, and FIG. 3 is a DTV signal using the present embodiment. FIG. 4 is a block diagram showing the configuration of the time shift system of FIG. 1, FIG. 4 is an explanatory diagram of a recording / reproducing operation of the present embodiment, FIG. 5 is an explanatory diagram of a first example of a recording method on a tape in the present embodiment, FIG. 6 is an explanatory diagram of a second example of a recording method on a tape in the present embodiment.

In the DTV signal recording section of the present embodiment, as shown in FIG. 1, an input terminal for receiving a demodulated VSB signal is provided, and this input terminal is provided with the demodulated VSB signal.
An AD converter 24A for AD-converting the signal and a synchronization / timing signal detection circuit 14 for extracting a synchronization / timing signal from the demodulated VSB signal are connected in parallel with each other, and an output terminal of the synchronization / timing signal detection circuit 14 And a servo circuit 27A for performing a servo operation at the time of recording.

At the output terminals of the AD converter 24A and the synchronization / timing signal detection circuit 14, when the rotary head is switched, a valid signal is sent to the newly switched rotary head. , So that the output signal of the AD converter 24A is
A time compression circuit 25 for compressing in the time axis direction is connected.

Various data are written into and read from the time compression circuit 25 during the time compression operation.
26A and a DA converter 28A for DA-converting the time-compressed signal, and an RF signal amplifier 29A for amplifying the obtained RF signal and supplying it to the rotary head as an excitation signal is connected to the DA converter 28A. And R
A rotary head is connected to the F signal amplifier 29A.

In the DTV signal reproducing section of the present embodiment, as shown in FIG. 2, the rotary head is connected to an RF signal amplifier 29B for amplifying recording information read by the rotary head, and the output of the RF signal amplifier 29B An AD converter is connected to the terminal, and an output terminal of the AD converter 24B is connected to a time expansion circuit 30 for canceling the time compression process performed by the time compression circuit 25 of the recording unit.

The output terminal of the time expansion circuit 30 is connected to a DA converter 28B for reproducing the demodulated analog VSB signal, and the output terminal of the DA converter 14 extracts a synchronization / timing signal from the analog VSB signal. The synchronization / timing signal detection circuit 14 is connected. Then, the synchronization / timing signal detection circuit 14 is connected to a time expansion circuit 30 and a comparison circuit 31 using an internal clock as a reference value. The comparison circuit 31 is connected to a servo circuit 27B for performing a servo operation during reproduction. ing.

As shown in FIG. 3, the DTV signal time shift system using the present embodiment has a VCR (video) comprising the DTV signal recording section and the DTV signal reproducing section of the present embodiment described above. Cassette recorder) 4
0 is the input terminal of the DTV described with reference to FIG.
VSB demodulated signal input / output terminal t1 of signal reception system
Is connected to an output terminal of the VCR 40, and a VSB modulator 8A is connected to an output terminal of the VCR 40.
The F up-converter 9A is connected.

The operation of this embodiment having such a configuration will be described. DTV by DTV signal recording section of the present embodiment
At the time of signal recording, the input / output terminal t1 of the VSB demodulated signal of the DTV signal receiving system shown in FIG. 8 is connected to the input terminal of the DTV signal recording unit, and the synchronization / timing signal detection circuit 14 operates as shown in FIG. And data and FEC
A field synchronization signal indicating the start position of the segment including the (error correction code) is detected, and the field synchronization signal is supplied to the servo circuit 27A and the time compression circuit 25.

In the servo circuit 27A, the recording operation of the recording section is controlled based on the field synchronization signal from the synchronization / timing signal detection circuit 14. In the time compression circuit 25, when the rotary head is switched, a new switching is performed. A valid signal is input to the rotating head to be used, and the output signal of the AD converter 24A is compressed in the time axis direction so that the valid signal is not input to the rotating head from which recording has been canceled.

Then, the servo circuit 27A records the information data of the segment section of 24.2 ms starting from the field synchronization signal in an analog value in one track section of the tape in synchronization with the rotation of the rotary head. In this case, the time compression circuit 25 causes the RF signal amplifier 2
The signal supplied to the rotary head from 9A is compressed in the time axis direction, and when the rotary head is switched, a valid signal is input to the newly switched rotary head, and a valid signal is supplied to the rotary head whose recording has been released. Is not input, thereby preventing occurrence of an abnormal operation when the rotary head is switched.

In this case, the information data is recorded on the tape, as shown in FIG. 5, by associating the signal level of the demodulated VSB signal with the frequency and using the rotary head 32 in the FM system.
6, or as shown in FIG. 6, the signal level of the demodulated VSB signal is associated with the amplitude and recorded on the tape by the rotating head 32 in the AM system. Is done.

The DTV signal reproducing unit according to the present embodiment
When the TV signal is reproduced, the data read from the tape and the information data for each segment including the FEC (error correction code) by the rotary head are transmitted to the RF signal amplifier 29B.
The signal is amplified by the A / D converter 24B, A / D converted by the A / D converter 24B, expanded in the time axis direction by the time expansion circuit 30, and the time compression by the time compression circuit 25 is released. The output signal of the time expansion circuit 30 is DA-converted by the DA converter 28B, and the demodulated VSB signal is reproduced and output as an analog signal. In this case, the field synchronization signal of the reproduced VSB signal is compared with the internal clock by the comparator 31, and the reproduction is performed in a state synchronized with the internal clock.

The VSB demodulated from the DTV signal reproducing unit
The signal is input to the input / output terminal t1 of the VSB demodulated signal of the DTV signal receiving system described with reference to FIG. 8, and the subsequent processing is performed by the receiving system.
The DTV signal written on the tape by the recording unit is reproduced by the reproducing unit, the video signal is displayed on the monitor of the DTV signal receiving system, and the speaker reproduces the sound of the reproduced audio signal.

As shown in FIG. 3, when a time shift system of a DTV signal is configured using the present embodiment, the input terminal of the VCR 40 is connected to the input / output terminal t1 of the DTV signal receiving system. The demodulated VSB signal is input, and the DCR of the VCR 40 is
The demodulated VSB signal is recorded as an analog signal on the tape of the TV signal recording section by the rotary head.

At the time of reproduction, the recorded VBS signal is read from the tape of the DTV signal recording section by the rotary head, and the demodulated VSB signal is output from the output terminal of the VCR 40. ,
VSB modulation for converting the transmission data into one set for every three bits and converting it into one of eight amplitude values is performed, and the RF up-converter 9A connected to the VSB modulator 8A performs RSB modulation.
It is output as an F signal. This RF signal is input to the input terminal of the tuner 12 of the DTV signal receiving system shown in FIG. 8, the receiving process is executed as described above, and the reproduced image of the video signal of the DTV signal is displayed on the monitor. The sound is reproduced and output from the speaker.

Therefore, the DTV signal time shift system allows the DTV signal to be swim-shifted for a desired time and output, allowing the viewer to view the DTV broadcast at the convenience of the viewer. Editing can be easily performed.

As described above, according to the present embodiment, DT
The V recording / reproducing device is composed of a simple circuit without complicated digital processing such as packet processing, shuffling processing, depacket processing, and deshuffling processing. , The recorded VSB DTV signal is read, and the DTV signal for reproducing the demodulated VSB signal can be easily recorded and reproduced. In addition, by using this embodiment to configure a time shift system of the DTV signal, the DTV signal is swim-shifted for a desired time and output, and the DTV broadcast can be viewed in accordance with the viewer's convenience. , DTV signals can be easily edited.

[0037]

According to the first aspect of the present invention, the detecting means detects the field synchronization signal from the demodulated analog signal of the DTV signal, and the synchronous recording means rotates the rotary head in synchronization with the field synchronization signal. The demodulated analog signal is recorded on the tape in the running state of the tape recorder via the rotating head, and at the time of reproduction, the rotating head is rotated by the synchronous reproducing means in synchronization with the field synchronization signal. Since the demodulated analog signal recorded through the DTV is reproduced, the recording and reproduction of the DTV signal can be easily performed with a simple circuit configuration without complicated digital processing.

According to the second aspect of the present invention, the field synchronization signal is detected from the demodulated VSB analog signal of the DTV signal by the detection means, and the rotary head is rotated by the synchronization recording means in synchronization with the field synchronization signal. The demodulated VSB analog signal is recorded on the tape in the running state of the recorder via the rotating head, and at the time of reproduction, the rotating head is rotated by the synchronous reproducing means in synchronization with the field synchronization signal. Since the demodulated VSB analog signal recorded through the DTV is reproduced, the recording and reproduction of the DTV signal can be easily performed with a simple circuit configuration without complicated digital processing.

According to the third aspect of the present invention, the detecting means detects the field synchronization signal from the demodulated analog signal of the DTV signal, and the synchronous recording means rotates the rotary head in synchronization with the field synchronization signal. The demodulated analog signal is recorded on the tape in the running state via the rotating head in association with the frequency, and at the time of reproduction, the rotating head is rotated by the synchronous reproducing means in synchronization with the field synchronization signal, and the tape in the running state is reproduced. From
Since the demodulated analog signal recorded via the rotary head is reproduced in association with the frequency, recording and reproduction of the DTV signal can be easily performed with a simple circuit configuration without complicated digital processing. .

According to the fourth aspect of the present invention, the detecting means detects the field synchronization signal from the demodulated analog signal of the DTV signal, and the synchronous recording means rotates the rotary head in synchronization with the field synchronization signal. The demodulated analog signal is recorded on the tape in the running state via the rotating head in association with the amplitude, and at the time of reproduction, the rotating head is rotated by the synchronous reproducing means in synchronization with the field synchronization signal, and the tape in the running state is reproduced. Since the demodulated analog signal recorded via the rotary head is reproduced in association with the amplitude, recording and reproduction of the DTV signal can be easily performed with a simple circuit configuration without complicated digital processing. become.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a DTV signal recording unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a DTV signal reproducing unit of the embodiment.

FIG. 3 is a block diagram showing a configuration of a DTV signal time shift system using the embodiment.

FIG. 4 is an explanatory diagram of a recording / reproducing operation of the embodiment.

FIG. 5 is an explanatory diagram of a first example of a recording method on a tape in the embodiment.

FIG. 6 is an explanatory diagram of a second example of a recording method on a tape in the embodiment.

FIG. 7 is an explanatory diagram showing a configuration of a DTV signal transmission system.

FIG. 8 is an explanatory diagram showing a configuration of a DTV signal receiving system.

FIG. 9 is a block diagram illustrating a configuration of a recording unit of a conventional DTV signal recording / reproducing apparatus.

FIG. 10 is a block diagram showing a configuration of a reproducing unit of a conventional DTV signal recording / reproducing apparatus.

[Explanation of symbols]

12 Tuner, 13 Intermediate frequency filter and synchronous detector, 14 Synchronization / timing signal detection circuit, 18 Trellis decoder, 20 Reed-Solomon decoder, 25
... Time compression circuit, 26A, 26B ... RAM, 27A, 2
7B: servo circuit, 30: time expansion circuit.

Claims (4)

[Claims] 1. A DTV signal is recorded on a tape recorder provided with a rotary head, and the DT recorded on the tape recorder is recorded.
A DTV signal recording / reproducing apparatus for reproducing a V signal, a detecting means for detecting a field synchronization signal from a demodulated analog signal of the DTV signal, and rotating the rotary head in synchronization with the field synchronization signal. Synchronous recording means for recording the demodulated analog signal on a tape in a running state of the tape recorder; and rotating the rotary head in synchronization with the field synchronization signal to obtain the demodulated analog signal from the tape in a running state. A DTV signal recording / reproducing apparatus, comprising: synchronous reproducing means for reproducing a signal. 2. The DTV signal recording / reproducing apparatus according to claim 1, wherein the demodulated analog signal is a demodulated VS signal.
A DTV signal recording / reproducing device, which is a B signal. 3. The DTV signal recording / reproducing apparatus according to claim 1, wherein said synchronous recording means records said demodulated analog signal on said tape in association with a frequency. apparatus. 4. The DTV signal recording / reproducing apparatus according to claim 1, wherein said synchronous recording means records said demodulated analog signal on said tape in association with an amplitude. apparatus.