JPH07162802A - Digital signal processing circuit - Google Patents

Abstract

PURPOSE:To improve precision for detecting the kind of a video signal and a recording compressing system at the time of reproduction concerning a data recording method for recording and reproducing digital data. CONSTITUTION:At the time of reproduction, a synchronizing block detection & ID detection circuit 51 detects an ID 56 of a synchronizing block from regenerative digital data. A representative value deciding circuit 52 outputs a representative value 57 in one track of a track number contained in the ID based on the detected ID 56 and a head switch 59 showing the partition of tracks. A video signal deciding circuit 53 decides the kind of the video signal recorded on a regenerative tape by checking the range and cyclicity of the track number representative value 57 and outputs a signal 58 expressing the kind of the video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal processing circuit for discriminating a recording / broadcasting system in a digital recording / reproducing apparatus for recording / reproducing digital data.

[0002]

2. Description of the Related Art In recent years, digital recording / reproducing technology has been applied to a wide variety of fields, and has made remarkable progress, especially in the field of digital AV, and in the rotary head system for business use, D1, D2, D3 system digital video, etc. Has been put to practical use.

Further, with the progress of image compression technology and high-density recording technology typified by MPEG, development of compact, high-performance and inexpensive home digital video has been reported by each electric appliance manufacturer.

The recording pattern in digital recording is
It looks like this: One track is composed of an audio area for recording audio, a video area for recording video, and a subcode area for recording auxiliary data, and these tracks are recorded in parallel on a recording medium. Also, each signal area is composed of a plurality of synchronization blocks. This sync block has a sync pattern indicating the beginning of the blocked digital data and I indicating the position of the information data.
D and an ID parity for detecting or correcting an error in the ID and information data.

Here, a plurality of types of video signals, for example N
When TSC or PAL is recorded, the recording pattern is different because the period and the signal amount of one frame of the video signal are different. In order to record this, there is a method in which the pattern of one track is made the same and the number of tracks constituting one frame is changed. Then, information indicating the type of video signal to be recorded in the subcode area is recorded. This has the advantage of recording different types of video signals in the same recording format.

At the time of reproduction, by demodulating the information indicating the type of the video signal in the subcode area, it is possible to perform a reproduction process suitable for the recording system.

This is an effective method for determining the type of video signal at the time of reproduction, such as the current broadcasting system (SD) and high definition system (HD) as well as NTSC and PAL.

It is also possible to put the information indicating the type of video signal in a part of the information data in the sync block of the audio area or the video area instead of the subcode area.

Further, there can be considered a recording method in which the number of tracks constituting one frame is different by changing the compression rate when recording the same video signal. For example, the recording time can be increased instead of increasing the compression rate and degrading the image quality.

As with the above example, the determination of the recording method can be made at the time of reproduction by inserting the recording method information into a part of the information data in the sync block of the subcode area or the audio area or the video area. Is.

[0011]

However, in the above-mentioned conventional structure, the amount of information to be recorded is limited and, for example, information can be entered only once in one track. Therefore, when the reproduction state is poor, it is difficult to normally determine the type of video signal or the type of recording method.

Further, in order to improve the detection accuracy, multiple writing has to be performed, so that there is a problem that the recording density increases.

[0013]

In order to solve the above-mentioned problems, a digital signal processing circuit according to the first invention comprises a synchronization pattern indicating the beginning of blocked digital data, an ID indicating the position of information data, and the ID. 1 track area is constituted by a video signal area formed by connecting a plurality of synchronization blocks composed of ID parity for detecting or correcting the error and information data, an audio signal area, and a sub-code area for recording auxiliary data, In a digital recording / reproducing apparatus in which the tracks are arranged in parallel and recorded on a medium, and the number of tracks constituting one frame of a video signal differs depending on the type of the video signal, the ID of the sync block is detected from the reproduced digital data during reproduction However, a track that is information indicating the order of the tracks in the frame that is information in the ID By checking the periodicity of the issue of the range or number of the track determines the type of video signal recorded in the playback tape.

Also, in the digital new word processing circuit of the second invention, a synchronization pattern indicating the beginning of blocked digital data, an ID indicating the position of information data, and the ID
1 track area is constituted by a video signal area formed by connecting a plurality of synchronization blocks composed of ID parity for detecting or correcting the error and information data, an audio signal area, and a sub-code area for recording auxiliary data, In a digital recording / reproducing apparatus in which the tracks are arranged side by side on a medium and recorded in parallel, and the tracks constituting one frame of a video signal are different from each other depending on the recording compression method, the ID of the synchronous block is detected from the reproduced digital data during reproduction. The type of recording compression method recorded on the reproduction tape by checking the range of track numbers, which is information indicating the order of the tracks in the frame that is information in the ID, or the periodicity of the track numbers. To judge.

[0015]

Since a plurality of IDs in the sync block are present in one track, the detection accuracy is very high. Therefore, according to the present invention, with the above configuration, the type of video signal and the type of recording method can be accurately determined even when the reproduction state is poor.

Further, it is possible to make a determination based on the existing information (ID) without increasing the recording density as in the conventional example.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In order to explain the present invention, in a digital signal recording / reproducing apparatus for recording / reproducing a digital signal as an oblique track on a tape by two heads mounted on a cylindrical cylinder, one track is recorded. As the minute recording signal, consider a digital VTR which records an audio area for recording an audio signal, a video area for recording a video signal, and a subcode area for recording auxiliary data such as information for searching tape recorded contents and date and time information. . here,
The two heads have different azimuth angles.

The audio area and the video area are formed by connecting a plurality of identical synchronization blocks.

A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a sync block that constitutes an audio area and a video area. The synchronization block 5 includes a synchronization pattern 1 indicating the beginning of the blocked digital data, a 16-bit length ID2 indicating the position of the information data, an 8-bit length ID parity 3 for detecting or correcting an error of ID2, and 680 It consists of bit length information data 4. The ID includes a track number indicating the order of tracks in one frame.

FIG. 2 shows an example of the structure of a track. The track 9 records an audio area 6 made up of 14 sync blocks 5, a video area made up of 149 sync blocks 5, and auxiliary information such as tape record content search information and date / time information. It is composed of a subcode area 8.

Based on this track pattern, various video signals are recorded. FIG. 3 shows an example of recording in the NTSC system. Tracks 9 are recorded diagonally in parallel on the tape 10. Video signal 1 frame 13
The track number in the ID2 of the sync block 5 in the audio area 6 and the video area 7 is 10 tracks and takes a value of 0 to 4 as shown in the figure. Here, the track number is changed by two tracks, but since the azimuth recording is performed, it is possible to distinguish these two tracks.

FIG. 4 shows an example of recording in the PAL system. Tracks 9 diagonally parallel to each other in the tape 10
To record. One frame 23 of the video signal is composed of 12 tracks, and the track number in the ID2 of the sync block 5 in the audio area 6 and the video area 7 takes a value from 0 to 5 as shown in the figure.

Looking at the recording pattern at a cycle of 1 frame, one frame of NTSC is 60 Hz, while P
Since one AL frame is 50 Hz, the number of tracks forming one PAL frame is 6/5 times that of NTSC.

FIG. 5 shows an example of recording high definition. Tracks 9 are recorded diagonally in parallel on the tape 10. One frame 33 of the video signal is composed of 20 tracks, and the track numbers in the ID2 of the sync block 5 in the audio area 6 and the video area 7 take values from 0 to 9 as shown in the figure.

This is a case where one frame is set to 60 Hz and the amount of recorded information for high-definition television is assumed to be twice as large as the amount of recorded information for NTSC. Therefore, the number of tracks constituting one frame is twice that of NTSC.

FIG. 6 shows a digital signal processing circuit according to the first embodiment of the present invention. Sync pattern detection & ID during playback
The detection circuit 51 detects the ID 56 of the sync block and its trigger pulse 55 from the reproduced digital data 54. The representative value determination circuit 52 takes in the ID 56 detected in accordance with the trigger pulse 55, determines the track number by a majority vote, and a head switch 59 that indicates a track delimiter.
The track number 57 of the current track is output in units.
The video signal determination circuit 53 determines the type of the video signal recorded on the tape by checking the range of the track numbers and the periodicity of the track numbers with the head switch 59 and the track number 57, and determines the video signal. A signal 58 indicating the type of is output.

FIG. 7 shows an operation example of determining the representative value of the track numbers. The synchronization pattern detection & ID detection circuit 51 is
Although the ID (track number) 56 of the sync block in the reproduction data 54 is output, the ID is erroneously detected as indicated by the ID detection error 61. However, malfunction is eliminated by taking a majority decision of the ID (track number) detected by the representative value determination circuit 52. In addition, since there are 163 IDs in one track, they will not be undetected even if the reproduction state is a little bad.

FIG. 8 shows an operation example of the video signal determination circuit in the case of NTSC, FIG. 9 in the case of PAL, and FIG. 10 in the case of high-definition. Maximum track number 71,8
1, 91, or track number periodicity 72, 82,
By detecting 92, the type of video signal can be determined. 7 for maximum value check
It is possible to determine the type of video signal at the timing of 3,83,93. Further, in the case of periodicity check, it is possible to determine the type of video signal at the timings of 74, 84 and 94, respectively. In order to improve the detection accuracy of the video signal determination, it is preferable to use both the maximum track number value and the track number periodicity.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 11 shows a recording pattern when the NTSC signal is compressed to three fifths as compared with the recording pattern of FIG. This method has the advantage of increasing the recording time, instead of increasing the compression rate and degrading the quality of the image. Hereinafter, the pattern of FIG. 3 will be called SP and the pattern of FIG. 11 will be called LP.

Tracks 9 are recorded diagonally in parallel on the tape 10. The video signal 1 frame 43 is composed of 6 tracks, and the track number in the ID2 of the synchronous block 5 in the audio area 6 and the video area 7 takes a value from 0 to 2 as shown in the figure. Here, the track number changes by two tracks, but since the azimuth recording is performed, it is possible to distinguish between the two tracks.

FIG. 12 shows a digital signal processing circuit according to the second embodiment of the present invention. Sync pattern detection & I during playback
The D detection circuit 51 detects the ID 56 of the sync block and its trigger pulse 55 from the reproduced digital data 54. The representative value determination circuit 52 takes in the ID 56 detected in accordance with the trigger pulse 55, determines the track number by majority, and determines the track division by the head switch 5.
The track number 57 of the current track is output in units of 9. The recording system determination circuit 63 determines the type of the recording compression system recorded on the tape by checking the range of the track numbers and the periodicity of the track numbers with the head switch 59 and the track number 57, and the recording compression is performed. A signal 68 indicating the type of system is output.

An operation example for determining the representative value of the track number is the same as that of FIG. 7 described in the first embodiment.

In the case of NTSC SP in FIG. 8, N in FIG.
An operation example of the recording system determination circuit in the case of LP of TSC will be shown. It is possible to determine the type of the recording compression method by detecting the maximum values 71, 101 of the track numbers or the periodicity 72, 102 of the track numbers. In the case of the maximum value check, it is possible to determine the recording compression method at the timings 73 and 103, respectively.
In the case of periodicity check, it is possible to determine the type of recording compression method at the timings of 74 and 104, respectively. In order to improve the detection accuracy, it is preferable to use both the maximum value of track numbers and the periodicity of track numbers.

In the above recording pattern example, the track number is changed every two tracks using the azimuth angle, but the digital signal processing circuits of the first and second embodiments change the track number every track. The recording pattern is also effective, and generally, any recording pattern is effective as long as the numbering of the track number is provided so that the type of each video signal or the recording compression method can be distinguished.

Further, although the track pattern example is composed of the audio area, the video area, and the subcode area, one track is composed of one or more signal areas, and the signal areas include a plurality of track areas. The digital signal processing circuits of the first and second embodiments are effective as long as they are composed of the synchronization block.

Further, in the embodiment of the present invention, in order to obtain the representative track number, the majority decision is made by the representative value decision circuit. However, when the false detection of the sync pattern detection & ID detection circuit is extremely low, There is no need to take a majority vote.

In addition, when the value of the track number that can be detected by the ID detection is limited by the type of the target video signal or the recording method, the track number exceeding the upper limit cannot be detected, but if the periodicity of the track number is measured. good. For example, when reproducing a PAL tape in the NTSC system, only track numbers 0 to 4 can be detected, but the cycle of the track number is 12 tracks, so PA
It can be determined to be L.

In the actual configuration, all the digital circuits may be performed in the IC, but the video signal determination circuit and the recording system determination circuit may be processed by the microcomputer. Further, the representative value determination circuit can be included in the microcomputer.

[0039]

Since a plurality of IDs in the sync block exist in one track, the detection accuracy is very high.

Therefore, according to the present invention, the type of the video signal and the type of the recording system can be accurately determined even when the reproduction state is bad.

Further, it is possible to make a determination based on the existing information (ID) without increasing the recording density as in the conventional example.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a synchronization block.

FIG. 2 is a diagram showing an example of a track pattern.

FIG. 3 is a diagram showing an example of an NTSC tape pattern.

FIG. 4 is a diagram showing an example of a PAL tape pattern.

FIG. 5 is a diagram showing an example of a high-definition tape pattern.

FIG. 6 is a block diagram showing a configuration of a digital signal processing circuit according to a first embodiment of the present invention.

FIG. 7 is a timing chart showing an operation example of determining a representative value of track numbers of the digital signal processing circuit according to the first embodiment.

FIG. 8 is a timing chart showing an example of NTSC determination operation of the digital signal processing circuit according to the first embodiment.

FIG. 9 is a timing chart showing an example of PAL determination operation of the digital signal processing circuit according to the first embodiment.

FIG. 10 is a timing chart showing an example of an HDTV determination operation of the digital signal processing circuit according to the first embodiment.

FIG. 11 is a diagram showing an example of an NTSC LP tape pattern.

FIG. 12 is a block diagram showing the configuration of a digital signal processing circuit according to a second embodiment of the present invention.

FIG. 13 is a timing chart showing an example of an HDTV determination operation of the digital signal processing circuit according to the second embodiment.

[Explanation of symbols]

 1 sync pattern 2 ID 3 ID parity 4 information data 5 sync block 6 audio area 7 video area 8 subcode area 9 track 10 tape 13, 23, 33, 43 frame 51 sync pattern detection & ID detection circuit 52 representative value determination circuit 53 video Signal judging circuit 63 Recording method judging circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 27/28 A 8224-5D H04N 5/93 8224-5D G11B 27/28 A

Claims (2)

[Claims] 1. A plurality of synchronization blocks each composed of a synchronization pattern indicating the beginning of blocked digital data, an ID indicating the position of information data, an ID parity for detecting or correcting an error of the ID, and information data. In a digital recording / reproducing apparatus in which one track is composed of one or more signal areas, the track is recorded on a medium, and the number of tracks composing one frame of the video signal is different depending on the kind of the video signal Detecting the ID of the synchronization block from the digital data, and checking the range of track numbers, which is information indicating the order of the tracks in the frame, which is information in the ID, or the periodicity of the track numbers. According to the present invention, it has means for determining the type of video signal recorded on the reproduction tape. Digital signal processing circuitry for. 2. A plurality of synchronization blocks each composed of a synchronization pattern indicating the beginning of blocked digital data, an ID indicating the position of information data, an ID parity for detecting or correcting an error in the ID, and information data. In a digital recording / reproducing apparatus in which one track area is formed by one or more signal areas, the track is recorded on a medium, and one frame of a video signal is formed by a recording compression method for the same video signal, the number of tracks is different. During reproduction, the ID of the sync block is detected from the reproduced digital data, and a range of track numbers, which is information indicating the order of the tracks in the frame, which is information in the ID, or a cycle of the track numbers. By checking the compatibility, you can determine the type of recording compression method recorded on the playback tape. Digital signal processing circuit, characterized in that it comprises means for.