JPH052835A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable the reduction of a hardware scale and to minimize the increase of redundant degree by recording an audio signal for which an error correction encoding is performed by dividing them into at least two video/audio coexisting tracks. CONSTITUTION:A video/audio coexisting track 108 has two video recording areas 109, 110 and two audio recording areas 111, 112 and the video recording areas and audio recording areas are alternately arranged. This video/audio coexisting track is scanned by only two reproduction heads of 16 reproduction heads and the remaining 14 reproduction heads scan only a track used exclusively for video without scanning the video/audio coexisting track. In this case, the data amount per an audio recording area is increased and a reproduction is easily and stably performed. Only three edit gaps are used per 8 tracks and the redundant degree is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type magnetic recording / reproducing apparatus for recording a signal while forming a helical track on a magnetic tape by a rotary head, and more particularly to a digitized video signal and a digitized audio signal. For recording a digital VTR.

[0002]

2. Description of the Related Art A digital VTR records and reproduces a video signal and an audio signal in the form of a digital signal. Therefore, even if dubbing and editing are repeated, image quality and sound quality are not deteriorated, and high quality recording and reproduction is possible. Have an advantage.
Such digital VTRs have begun to spread from commercial use, and as the commercial use digital VTR, a component recording type D1 format VTR and a composite recording type D2 format VTR have been standardized and put into practical use.

FIG. 22 shows a D1 format digital V
It is a track pattern of a magnetic tape in TR. Since it is difficult to record the total amount of information of the digital video signal in one channel, in the component recording D1 format, the video signal is divided into four channels for recording. As shown in FIG. 22, each helical track is divided into video recording areas 2001 and 2002 and an audio recording area 2003, and edit gaps 2004 and 2005 are provided between the areas. The edit gaps 2004 and 2005 are gap regions provided for erasing and turning recording on / off while the head scans the video and audio signals independently of each other.

FIG. 23 shows a D2 format digital VT.
It is a track pattern on a magnetic tape in R. In the D2 format for composite recording, a video signal is divided into two channels and recorded on a magnetic tape. Figure 2
In 3 also, each helical track has a video recording area 2
101 and audio recording areas 2102 and 2103, and edit gaps 2104 and 2105.
Are separated by.

Although not shown in FIGS. 22 and 23, each audio recording area is actually divided into smaller recording areas, and an edit gap is also provided between each small area. Editing can be performed independently for each channel. 22 and FIG.
In FIG. 3, three tracks, that is, a time code track, a control track, and a cue audio track formed in the tape longitudinal direction are omitted.

In these conventional digital VTR formats, the digital audio signal is recorded on a part of the same helical track as the video signal. As a result, there is a great merit that the electromagnetic conversion system for recording and reproducing the audio signal and a part of the signal processor can be shared with that of the video signal. The common parts are mechanism system, recording / reproducing head, recording / reproducing amplifier, modulation / demodulation circuit, waveform equalization circuit, clock extraction circuit, synchronization detection circuit, and some error correction encoding / decoding circuits. .

Further, most of the devices compatible with these formats have the same number of audio pre-playback heads as the normal heads on the rotary drum. The preceding reproducing head has a mounting height changed with respect to the recording head so as to compensate for a delay time due to the reproduction processing and the recording processing of the audio signal, and is arranged so as to reproduce the signal ahead of a predetermined time. . By this head, the audio data pre-reproduced (read ahead) is processed (mixing, filtering, etc.), and the processed audio data can be recorded again at the same position on the tape.

By the way, as a next-generation television system, a high-definition television system having 1000 or more scanning lines has attracted worldwide attention. Although detailed standard has not been fixed yet, it is being developed as a high-definition system in Japan. HDTV has 1125 scanning lines and the aspect ratio of the screen is 9:16. The amount of information in HDTV is more than five times that of the current standard television system.

There is a 1-inch open reel type digital VTR as a high-definition digital VTR having such an enormous amount of information. This VTR is based on a 1-inch type C VTR, and a high-definition signal is divided into eight channels and digitally recorded without information amount compression. Audio signals are digitally recorded on long tracks utilizing a wide tape width. FIG. 24 shows a track pattern on a magnetic tape of a 1-inch open reel high-definition digital VTR, and video recording tracks 2201, 2022, 2203, 2204, 220.
5, 2206, 2207, and 2208 consist of helical tracks, and the audio recording track 2209 consists of longitudinal tracks (actually, 8 tracks). Also in FIG. 24, the time code track, the control track, and the cue audio track in the tape longitudinal direction are omitted.

In the high-definition digital VTR such as the high-definition digital VTR, a cassette type which is superior in operability to the open reel type is desired in the future. Therefore, it is necessary to newly determine the format of the cassette type high definition digital VTR. However, the format of the 1-inch open reel type HDTV VTR cannot be used as it is for the cassette type because of the following reasons. First, in the case of the cassette type, it is extremely difficult to increase the tape winding angle to nearly 360 ° as in the open reel type. In the case of the cassette type, the tape width is set to 3 / to reduce the mechanical load.
It is realistic to set it to 4 inches (about 19 mm) or less.

Regarding the audio signal recording method, 1
Assuming that the cassette has a tape width of 9 mm, it becomes difficult to record a multi-channel digital audio signal on the longitudinal track as in the case of the 1-inch high-definition digital VTR because the tape width becomes narrower. When recording a digital audio signal on a long track, in addition to the above-mentioned problems, it is necessary to prepare completely different electromagnetic conversion systems and signal processors for video and audio, and the labor of adjustment and maintenance increases. There is also a problem that the edge portion of the tape on which the longitudinal track is formed is easily damaged. Therefore, a format in which an audio signal is also recorded on the helical track is desired. However, D1 and D2
When the digital audio signal is divided and recorded on all channels as in the format, there are the following problems.

(1) The information amount of the audio signal per track is extremely smaller than that of the video signal, and there is a high possibility that the audio data will be lost due to a burst error. (2) Since it is necessary to provide an edit gap for all tracks, data redundancy increases.

(3) The same number of advance playback heads for audio as the normal playback heads must be attached. In addition, the number of channels of the rotary transformer also increases in response to the increase in the number of preceding reproducing heads. In a multi-channel recording VTR of about 8 channels, it is wasteful to additionally install the corresponding number of pre-playback head rotary transformers only for audio editing.

[0014]

As described above, when an audio signal is recorded on a longitudinal track like the conventional open reel type digital VTR, a completely different electromagnetic conversion system and signal processor are used for the video signal and the audio signal. In addition to having to prepare it, there was a problem that the effort of adjustment and maintenance increased.

On the other hand, the conventional digital VTR technology is
Since the digital audio signal is divided and recorded on all channels, when applied to a cassette type digital VTR for high definition television, the information amount of the audio signal per track becomes extremely small and the audio data becomes vulnerable to a burst error. However, there has been a problem that the redundancy for providing an edit gap on each track is increased, and the number of pre-read heads and the number of channels of the rotary transformer are greatly increased.

An object of the present invention is that a circuit portion for processing a video signal can also be used for processing an audio signal, the audio data is strong against a burst error, the redundancy is increased, the number of preceding reproducing heads and the rotary head are increased. It is an object of the present invention to provide a rotary head type recording / reproducing apparatus having a format suitable for a cassette type digital VTR for high definition television, in which an increase in the number of transformer channels is minimized.

[0017]

According to the present invention, a rotary head is used to form a plurality of helical tracks on a magnetic tape, and a digitized video signal and a digitized audio are formed on these helical tracks. A rotary head type magnetic recording / reproducing apparatus for recording a signal has (N−K) tracks per N helical tracks as video-only tracks, and the remaining K tracks among the N helical tracks are recorded.
A book is used as a video / audio mixed track, and video signals are recorded on the video-only track and the video / audio mixed track, and error correction data is added to the audio signal of a predetermined period, and at least an audio signal encoded by error correction is recorded. It is configured to be divided into two video / audio mixed tracks for recording.

More specifically, for example, an error correction data equal to or more than the original data is added to the audio signal of a predetermined period, and these data are divided into two video / audio mixed tracks and each of them is divided. In the mixed video / audio track, the data is recorded in two or more audio recording areas so as to be separated in the recording area of the video signal.

Further, according to the present invention, the signals recorded on the dedicated video track and the mixed video / audio track are reproduced by at least N reproducing heads, and the predetermined reproducing head mixes the predetermined video / audio. The audio recording area portion of the video / audio mixed track preceding the predetermined video / audio mixed track by a predetermined time is arranged to be reproduced during the reproduction of the audio recording area portion of the track. At least K audio advance reproducing heads are provided, and a signal reproduced by a predetermined reproducing head and a signal reproduced by a predetermined audio preceding reproducing head are switched and supplied to the rotary transformer.

In other words, K reproducing heads are provided for every N reproducing heads, and a predetermined reproducing head reproduces a portion of the audio recording area in a predetermined video / audio mixed track and a predetermined period. The audio pre-playback heads are arranged such that the periods during which the audio pre-playback heads play the portion of the audio recording area in the video / audio mixed track that precedes the predetermined video / audio mixed track by a predetermined time.

The switching means is provided in the rotary drum, and in the audio advance reproduction mode, supplies a signal from a predetermined audio advance reproduction head to the rotary transformer instead of a signal from a predetermined reproduction head during the reproduction period of the audio recording area. To be controlled.

Further, in the present invention, the effective video signal data amount per one video dedicated track and the effective video signal data amount per one video / audio mixed track are as simple as 2: 1. It is desirable that the ratio is an integer.

[0023]

According to the present invention, the video signal is recorded on the video-only track and the video / audio mixed track, and the audio signal is recorded on the video / audio mixed track. The processor is shared with that of the video signal. Also, by concentrating the audio data on a part of the tracks, the amount of information of the audio signal per audio recording area increases and the burst error becomes strong. At the same time, the redundancy due to the edit gap increases and the necessary pre-reproduction is performed. The increase in the number of heads and channels of the rotary transformer is prevented.

Further, according to the present invention, the error-correction-encoded audio signal obtained by adding the error correction data to the audio signal of the predetermined period is divided into a plurality of video / audio mixed tracks and recorded. Even though the audio signals are concentrated on some tracks and recorded, they are not weakened by the clogging of the head.

Further, in the present invention, since the audio pre-playback head is provided in the above arrangement, the dedicated rotary transformer for the audio pre-playback head becomes unnecessary.

Further, when the data amount of the effective video signal per one track dedicated to video and the data amount of the effective video signal per one track mixed with video and audio are recorded as a simple integer ratio, the video to each track is recorded. Data distribution rules are simplified.

[0027]

Embodiments will be described below with reference to the drawings. A first embodiment of the present invention will be described for a high-definition cassette type digital VTR for high-definition television systems. First, the video / audio data to be recorded will be described.

The video signal does not need to be recorded in the sync signal portion, and the effective data actually recorded is as follows. The number of effective lines per frame is 1080 (1
The number of effective samples per line is 1920 for luminance signals (Y signals) and 960 for color signals (PB, PR signals). The field frequency is 60 Hz. The number of quantization bits of the video signal is 8 bits. The audio signal has a sampling frequency of 4
It is assumed that 4 channels are recorded as a PCM audio signal of 8 kHz and a maximum of 20 bits / sample. All of these data are recorded without compressing the information amount.

The number of divided channels of the VTR is the same as that of the above-described 1-inch open reel type high-definition digital VTR, and recording / reproduction is performed with 8 channels. However, as described above, the wrap angle of the cassette type is not as large as that of the open reel type, so when scanning with eight recording heads (and eight reproducing heads), the idle time of the head (actually the tape (The time during which recording / playback is not performed) becomes longer, and the actual recording data rate decreases. Therefore, as shown in FIG. 1, 16 recording heads R1 to R16 and 16 reproducing heads P1 to P16 are mounted on a rotary drum RD, and a wrapping angle is set to 180 degrees, and two opposing heads are switched. The method used while That is, 16
Eight of the recording (or reproducing) heads are always in the active state. At this time, the signals to the two recording heads (and the signals from the two reproducing heads) are set to 1
By mounting a circuit for switching every 80 degrees on the rotary drum and using the rotary transformer in a time-division manner, the number of channels of the rotary transformer can be reduced to 8 recording / reproducing channels. In this case, the number of signal processing processors for recording / reproduction may be 8 channels. Since the rotating drum rotates 150 times per second (2.5 rotations per field), the number of tracks per field is 40 (= 2.5 × 16) tracks.

FIG. 2 shows a track pattern on the magnetic tape in this embodiment. Of the N = 8 tracks scanned by the eight heads corresponding to the half rotation of the rotary drum, N−K = 7 are used as video dedicated tracks 101, 10
2, 103, 104, 105, 106, 107 and the remaining K = 1 are used as the video / audio mixed track 108. The video / audio mixed track 108 is provided with video recording areas 109 and 110 and audio recording areas 111 and 112. Also in FIG. 2, the time code track, control track and cue audio track in the tape longitudinal direction are
Since it is not directly related to the gist of the present invention, it is omitted from the drawing. Next, the contents of each of the tracks 101 to 108 will be described.

The total number of symbols in one track is the same for both the video-only track and the video / audio mixed track. Video dedicated tracks 101, 102, 103,
Each of 104, 105, 106, and 107 includes only a video recording area as shown in FIG. 3, and each video recording area includes a preamble 201, a video data section 202, and a postamble 203. Preamble 20
Reference numeral 1 denotes a portion provided to lock the PLL (Phase Locked Loop) of the clock extraction circuit prior to the video data section 202, and the postamble 203 ensures the reproduction to the end of the video data section 202. These are provided portions and both play a role of protecting the video data portion 202.

Video / audio mixed track 108
Shows two video recording areas 109, 1 as shown in FIG.
10 and two audio recording areas 111 and 112, and video recording areas and audio recording areas are alternately arranged. In each recording area 109-112,
Areas 301, 304, 307 and 310 are preambles,
Areas 303, 306, 309 and 312 are postambles, areas 302 and 305 are video data portions and area 30.
Reference numerals 8 and 311 are audio data portions. The preamble and postamble protect the data portion of each area as described above. Further, edit gaps 113 and 11 are provided between the recording areas 109 to 112, respectively.
4, 115 are provided, which allows the video signal and the audio signal to be independently edited.

FIG. 5 shows the structure of a synchronization block which is a recording unit of each track 101-108. The structure of the sync block is the same in the video recording area and the audio recording area. The sync block includes sync patterns 401, I.
D and its parity symbol 402 and data and its parity symbol 403. The data and its parity symbol (error correction code) portion is composed of two C1 codewords described later (each data portion is 108 symbols and parity portion is 6 symbols, for a total of 114 symbols). The ID is an address for identifying which track and which block the sync block to which it belongs is. Next, a specific configuration of the VTR having the above-mentioned format according to this embodiment will be described.

FIG. 6 is a schematic configuration diagram of the recording signal processing circuit in this embodiment. This recording signal processing circuit includes video A / D conversion circuits 501a to 501c, serial-parallel conversion / channel distribution circuit 502, first recording processing circuits 503a to 503h, inter-head interleaving circuit 504, video C1 shuffling circuits 505a to 505a.
5h, audio A / D conversion circuit 511, audio C
2 shuffling circuit 512, audio C2 encoding circuit 513, audio C1 shuffling circuit 514,
Video / audio switching circuit 521, second recording processing circuits 506a to 506h, rotary transformer 507
a to 507h, recording amplifiers 508a to 508p, and recording heads R1 to R16.

First recording processing circuits 503a to 503h
The video C2 shuffling circuit 601 and the video C2 encoding circuit 60 have an internal configuration as shown in FIG.
It consists of two.

Second recording processing circuits 506a to 506h
The internal configuration of the C1 code encoding circuit 701, the modulation circuit 702, and the synchronization / ID addition circuit 70 is as shown in FIG.
3 and a parallel-serial conversion circuit 704.

In FIG. 6, input analog video signals (Y, PB, PR signals) are video A / D conversion circuits 50.
The signals 1a to 501c are converted into 8-bit digital signals, which are further distributed to 8 channels in the serial-parallel conversion / channel distribution circuit 502. This processing lowers the data rate of each channel, and the processing clock can be lowered accordingly. Therefore, after the serial-parallel conversion / channel distribution circuit 502, the ECL
There is no need to use high speed devices such as. In the first recording processing circuits 503a to 503h, the video C2 shuffling circuit 601 using a relatively small-sized memory rearranges the data within the video line, and the video C
The 2-encoding circuit 602 encodes the video C2 error correction code. Next, an interleave circuit 504 between heads
Thus, the data is redistributed to each track in order to improve the burst error correction capability. The video C1 shuffling circuits 505a to 505h perform rearrangement of data again by using a relatively large-scale memory and, at the same time, serve as a data buffer.

On the other hand, the 4-channel input analog audio signal is converted by the audio A / D conversion circuit 511 into a digital signal having a sampling frequency of 48 kHz and a maximum of 20 bits. Next, data rearrangement is performed in the audio C2 shuffling circuit 512,
The audio C2 error correction code is encoded by the audio C2 encoding circuit 513. The audio C1 shuffling circuit 514 plays a role of a data buffer while rearranging data again.

In the video / audio switching circuit 521, the channel 1 C1 shuffling circuit 50 is used.
The video data from 5h and the audio data from the audio C1 shuffling circuit 514 are switched and multiplexed at a predetermined timing. Second recording processing circuit 506
In a to 506h, the C1 code encoding circuit 701 encodes the C1 error correction code, and the modulation circuit 702 performs data modulation according to the characteristics of the magnetic recording / reproducing system.
The synchronization / ID addition circuit 703 adds the synchronization pattern / ID and the preamble / postamble, and the parallel / serial conversion circuit 704 converts the data into serial data. The 8-channel serial data is transmitted into the rotary drum via the rotary transformers 507a to 507h, amplified by the recording amplifiers 508a to 508p, and recorded on the magnetic tape by the recording heads R1 to R16. The recording heads are mounted on the rotary drum in the order of R1, R2, ..., R16 at equal intervals.
9, R2 and R10, ..., R8 and R16 are at 180-degree opposite positions. Recording amplifiers 508a and 508i, 508
Any one of b and 508j, ..., 508h and 508p is activated depending on the phase of the rotary drum.

FIG. 9 is a timing chart at the time of recording, and the hatched portion shows recording data supplied to eight recording heads (for example, R1 to R8) corresponding to half rotation of the rotary drum. The video data of channel 1 to channel 8 is video C1 at the timing shown in FIG.
It is read from the shuffling circuits 505a to 505h. On the other hand, audio data is also read from the audio C1 shuffling circuit 514 at the timing shown in FIG. On channel 8, these data are video
Switched in the audio switching circuit 521,
Is multiplexed. By such a method, audio data can be recorded only on a part of one track (video / audio mixed track 108) of the eight helical tracks.

FIG. 10 is a schematic block diagram of the reproduction signal processing circuit in this embodiment. The reproduction signal processing circuit includes reproduction heads P1 to P16, an audio preceding reproduction head A8,
A16, regenerative amplifiers 901a to 901p, 911a, 9
11b, rotary transformers 902a to 902h, 91
2, first reproduction processing circuits 903a to 903h, 913,
Video / audio switching circuit 931, video C1 deshuffling circuits 904a to 904h, head-to-head deinterleaving circuit 905, video second reproduction processing circuit 9
06a-906h, video channel integration / parallel-
Serial conversion circuit 907, video D / A conversion circuit 908
a-908c, audio switching circuit 932, audio C1 deshuffling circuit 921, audio C2
It is composed of a code decoding circuit 922, an audio C2 deshuffling circuit 923, an audio error correction circuit 924, and an audio D / A conversion circuit 925.

The first reproduction processing circuits 903a to 903h,
Reference numeral 913 is a circuit that performs processing corresponding to the second recording processing circuit in FIG. 6, and as shown in the internal configuration of FIG. 11, the waveform equalization circuit 1001 and the clock extraction circuit 100.
2, data identification circuit 1003, serial-parallel conversion circuit 1004, synchronization detection circuit 1005, demodulation circuit 100
6, ID identification circuit 1007 and C1 code decoding circuit 10
It consists of 08.

Second reproduction processing circuits 906a to 906h
Is a circuit for performing processing corresponding to the first recording processing circuit in FIG. 6, and as shown in the internal configuration of FIG.
Video C2 code decoding circuit 1101, video C2 deshuffling circuit 1102 and video error correction circuit 110
It consists of three.

In FIG. 10, a signal reproduced from the magnetic tape by the reproducing heads P1 to P16 is a reproducing amplifier 90.
Amplified by 1a to 901p, rotary transformer 9
It is taken out from the rotating drum via 02a to 902h. The reproducing heads P1, P2, ..., P16 are mounted in this order on the rotating drum at equal intervals.
, P9, P2 and P10, ..., P8 and P16 are at 180 ° opposite positions. Regenerative amplifiers 901a and 901i, 9
One of 01b and 901j, ..., 901h and 901p is made active according to the rotation phase of the rotary drum, and signals from two reproducing heads facing each other by 180 degrees are multiplexed in the rotary drum. .

In the reproduction processing circuits 903a to 903h, the 8-channel reproduction signal is waveform equalized by the waveform equalization circuit 1001, the data clock is extracted by the clock extraction circuit 1002, and the data identification circuit 1003.
0 or 1 bit identification is performed by the serial
It is converted into 8-bit parallel data by the parallel conversion circuit 1004. Further, the sync detection circuit 1005 detects and protects the sync pattern from the reproduced signal,
The demodulation circuit 1006 performs reverse processing of modulation, that is, demodulation, the ID identification circuit 1007 identifies and protects the ID of the synchronization block, and the C1 code decoding circuit 1008 decodes the C1 error correction code. In channel 8, the video / audio switching circuit 931 switches video data and audio data at a predetermined timing and separates them. The timing at this time is the same as in FIG.

Video C1 using a relatively large scale memory
The deshuffling circuits 904a to 904h function as data buffers, and at the same time perform the reverse processing of the video C1 shuffling circuits 505a to 505h. The inter-head deinterleave circuit 905 performs the reverse processing of the inter-head interleave circuit 504. Reproduction processing circuits 906a-9
In 06h, the video C2 code decoding circuit 1101 decodes the video C2 error correction code, and the video C2 deshuffling circuit 1102, which uses a relatively small memory, performs the reverse processing of the video C2 shuffling circuit 601.
The video error correction circuit 1103 interpolates data that cannot be error-corrected according to the data near the screen. Furthermore, video channel integration / parallel-serial conversion circuit 907
Integrates channels. The output of the video channel integration / parallel-serial conversion circuit 907 is converted into output analog video signals (Y, PB, PR signals) by the video D / A conversion circuits 908a to 908c.

On the other hand, the video / audio switching circuit 9
The audio data separated in 31 is supplied to an audio switching circuit 932 described later. The output of the audio switching circuit 932 is supplied to the audio C1 deshuffling circuit 921. The audio C1 deshuffling circuit 921 plays the role of a data buffer and at the same time performs the reverse processing of the audio C1 shuffling circuit 514, and the audio C2 code decoding circuit 922 decodes the audio C2 error correction code. Audio C2
The deshuffling circuit 923 performs the reverse processing of the audio C2 shuffling circuit 512, and the audio error correction circuit 924 interpolates the error-uncorrectable data by the preceding and following data. The output of the audio error correction circuit 924 is converted into a 4-channel output analog audio signal by the audio D / A conversion circuit 925.

The signals reproduced from the magnetic tape by the audio preceding reproduction heads A8 and A16 are amplified by the reproduction amplifiers 911a and 911b and taken out from the rotary drum via the rotary transformer 912. Audio preplay heads A8 and A16 are 1 on the rotating drum
Video at a position facing 80 degrees, and a certain time ahead
It is arranged to scan mixed audio tracks.

Either one of the regenerative amplifiers 911a and 911b is activated depending on the rotation phase of the rotating drum,
The signals from the audio preplay heads A8 and A16 are multiplexed in the rotating drum. The audio switching circuit 932 selects one of the preceding reproduction audio signal and the reproduction audio signal from the reproduction head P8 or P16 which have been processed in the reproduction processing circuit 913 in the same manner as the reproduction processing circuits 903a to 903h. The audio switching circuit 932 selects the preceding reproduction signal only when the audio is edited as described above.

6 and 10, for simplification, the digital input / output circuit for video / audio mounted in the actual device and the circuit for special reproduction (shuttle reproduction, slow reproduction, etc.) are omitted. ing.

As described above with reference to FIGS. 1 to 12, K tracks of N tracks are used as mixed video / audio tracks, and only some of the reproducing heads or recording heads are mixed video / audio tracks. To scan. That is, in the first embodiment, an audio recording area as a video / audio mixed track is provided only in K = 1 track for N = 8 tracks. This mixed video / audio track is scanned by only two of the 16 reproducing heads, and the remaining 14 reproducing heads scan only the video-only track without scanning the mixed video / audio track. Therefore,
In a conventional device in which audio data is recorded in a distributed manner on all tracks, 16 audio pre-reproduction heads and 8-channel pre-reproduction rotary transformers are required. Two pre-playback heads and one channel for the pre-playback rotary transformer. Further, when audio data is distributed and recorded on all tracks, at least eight audio recording areas and at least eight edit gaps are required per eight tracks, whereas in the present embodiment, the audio recording areas are Since there are two data per eight tracks, the amount of data per audio recording area is large, and stable reproduction is facilitated. Further, the edit gap may be three per eight tracks, and the increase in redundancy can be suppressed.

Next, more concrete description will be given of how the video signal and the audio signal are processed in this embodiment. However, in the following description, the main purpose is to explain the content of the process in an easy-to-understand manner, and FIGS.
It does not necessarily correspond to the actual order of processing in the circuit. First, the processing of the audio signal will be described.

In this embodiment, 4-channel digital audio signals are recorded and reproduced, but the audio signal processing is completed in units of 2/5 fields. This unit corresponds to a two segment period of video (described later). The number of audio samples per channel during this period is 3
20 samples (= 4800 ÷ 60 × 2/5). 1 for each of these even and odd samples
Each sample is separated, and 160 samples are used as a unit for error correction processing. Since the number of bits per sample is 20 bits (maximum), this number of bits corresponds to 400 symbols (1 symbol = 8 bits). One error correction matrix is configured with the audio data of 400 symbols as a unit.

The structure of the audio error correction matrix is shown in FIG. First, auxiliary data of 32 symbols is added to data of 400 symbols to form a total of 432 symbols. These symbols are 4 vertical symbols ×
It is arranged in 108 symbols horizontally. At this time, two-stage C2
And C1 shuffling (permutation) are performed, thereby enhancing the effect of error correction when error correction is impossible. That is, first, 6-symbol C2 parity data is vertically added to 4-symbol data. Then 1
Six symbols of C1 parity data are laterally added to 08 symbols of data or C2 parity. The configuration of the C1 code is common to the video, and the C1 code encoding circuit is commonly used for the C1 code and the video. By performing encoding in two directions in this way, the correction capability for both random error and burst error is enhanced.

The 10 C1 codewords of the error correction matrix of FIG. 13 thus generated are divided into two groups (group 1 and group 2) of 5 pieces each. Four
The above process is repeated for each of the channels,
4 C1 codewords, 5 assigned to each channel
A data group composed of 20 C1 code words is formed by collecting channels. As a result, a total of four data groups including even sample group 1, group 2, odd sample group 1, and group 2 are generated. These data groups will be referred to as E1, E2, O1 and O2 in order.
As shown in FIG. 5, one synchronization block includes two C1s.
Since each data group includes a codeword, each data group includes 10 synchronization blocks.

These data groups are divided and recorded in four separate areas on the tape as shown in FIG. 2 videos
2 audio mixed tracks 1301 and 1302
Scanned by two different heads. Between the video / audio mixed tracks 1301 and 1302, there are seven video-only tracks (not shown). Area 13
Reference numerals 21, 1322, 1323, 1324 are video recording areas, and audio recording areas 1311, 1312, 13
Reference numerals 13 and 1314 correspond to E1, O2, O1 and E2, respectively. The timing of supplying audio data to the video / audio switching circuit 521 is adjusted so that E1 and O2 and O1 and E2 are recorded on the two video / audio mixed tracks in this manner. In this way, the audio recording area is formed in the central portion and the rear portion of the two video / audio mixed tracks so as to sandwich the video recording area.

Here, in the C2 error correction code, since the error correction data of 6 symbols is added to the original data of 4 symbols, the error is detected by the C1 error correction code and the erasure correction is performed by the C2 error correction code. For example, as is well known, errors in C2 error correction code words up to 6 symbols can be completely corrected (for example, when Reed-Solomon code is used). Generally, if the same amount of C2 error correction symbols as this data (the same number of symbols) or more is added to the original data, by using a C1 code or the like for error detection, at least half of the C2 error correction codeword can be obtained. Errors can be corrected by erasure correction. In this embodiment, 10 symbols of an arbitrary C2 error correction codeword are divided into data groups E1 and E2 (O1 and O2) by 5 symbols by the above-described processing. That is, the error-correction-coded audio signal is divided and recorded in two or more video / audio mixed tracks scanned by two or more different heads. Therefore, even if one of the two heads scanning the video / audio mixed track cannot be reproduced due to clogging or the like, either one of the data groups E1 and E2 and one of the data groups O1 and O2 can be reproduced. Since one of them is reproducible, it is possible to completely correct the error. Further, even if two audio recording areas along the longitudinal direction of the tape cannot be reproduced at the same time, either one of the data groups E1 and E2 and one of the data groups O1 and O2 can be reproduced, so that the error correction is completely performed. Is possible. In other words, the number of heads involved in audio signal reproduction) or recording) may be at least two or more.

Further, even if any three of the four audio recording areas shown in FIG. 14 cannot be completely reproduced, either the even sample or the odd sample can be completely corrected. Good quality error correction is possible.

Generally, if the audio data is intensively recorded on a part of the tracks, the audio data will be weakened due to the clogging of the head, but in the present embodiment, the data is distributedly recorded on a total of four areas of two tracks. This prevents the audio data from becoming weak against head clogging and burst errors. Generally, it is said that the lowest data error rate in one helical track is in the track central portion, followed by the track rear portion and the track front portion. Therefore, in order to reduce the error rate of audio data and the possibility that the data will be erroneous at the same time, the arrangement of this embodiment is effective.

Next, the processing of the video signal will be described. As in this embodiment, one track out of eight tracks is used as a mixed video / audio track, and the other seven tracks are used.
When the book track is used as a video-only track, the recording format of the video signal can be very complicated. However, in the present embodiment, the recording format of the video signal is formed so as to be as complicated as possible as described below.

First, the video signal corresponding to the screen of one field (540 lines) is divided into five segments of 108 lines each. One segment corresponds to eight tracks (seven video-only tracks and one video / audio mixed track), and video signal processing is completed in one segment. One segment of video data is distributed to a total of 64 error correction matrices. The structure of one video error correction matrix is shown in FIG. In each error correction matrix, the effective video data is 60 vertical symbols ×
It is formed by arranging in horizontal 108 symbols. At this time, shuffling (rearrangement) of two stages of C2 and C1 is performed together with the distribution between the error correction matrices, whereby the effect of error correction when error correction is impossible is enhanced.
C2 codewords are arranged in the vertical direction, and these C2 codewords have 3
C2 parity symbols of symbols are added, C1 code words are arranged in the horizontal direction, and C1 parity symbols of 6 symbols are added to these C1 code words. By performing encoding in two directions in this way, the correction capability for both random errors and burst errors can be improved.

Thereafter, interleaving between heads is performed in order to further improve the burst error correction capability. Specifically, eight rows (each eight C1 error correction codewords) from the top of each error correction matrix (all 63 rows) are distributed to the track 1, the track 2, ..., The track 8 in order.
However, 7 lines are distributed only to the last track 8. Of these, the last three rows distributed to the track 8 are C1 error correction codewords related to C2 parity data. After all,
C1 error correction code words relating to valid video data of 8 lines are distributed to tracks 1 to 7 and 4 lines are distributed to track 8.
Therefore, the data amount of the effective video signal of the track 8 which is the video / audio mixed track is exactly half the data amount of the effective video signal of the track 1 (to 7) which is the video dedicated track. In each track, C1 error correction codewords in the same row of all error correction matrices, that is, 64 C1 error correction codewords, are successively arranged in order. Since one C1 error correction codeword is included in one synchronization block, the data for one row of the entire error correction matrix is 32.
It will include a sync block. As a result, 32 sync blocks are interleaved for each C2 codeword. Eventually, track 1 (~ 7) has 256
(= 32 × 8 rows) synchronization blocks are recorded. Also, track 8 which is a video / audio mixed track
The video data corresponding to 224 (= 32 × 7 rows) sync blocks of the two video recording areas 109 and 11 in FIG.
The data is divided into 0 and divided into 112 synchronous blocks and recorded. The correspondence between the video data on the screen and each track will be described.

Each pixel data passes through any error correction matrix and is finally distributed to any track. Considering head clogging and burst error,
It is desirable that the data in the same track be as far apart as possible on the screen. FIG. 16 shows the distribution pattern of the Y signal to each track, and the numbers 1 to 8 indicate the track numbers. This distribution pattern has the following features. First, the data of not only the same track but also the data of adjacent tracks are separated from each other on the screen as much as possible. Also, horizontal 15 samples × vertical 2 lines are unit blocks of the distribution pattern, and in this, tracks 1 to 7 appear four times, whereas track 8 has two.
Appears only once. Since the distribution pattern has a horizontal 15-sample period in this way, there is no fraction for one video line (1920 samples for the Y signal). This is because the number of effective samples 1920 is divisible by 15. The PB and PR signals are also distributed to the tracks in the same pattern as the Y signal. That is, the amount of effective video data on the track 8 is exactly half that of the other tracks. This is as described above.

As described above, the data amount of the effective video signal of the video-only track and the data amount of the effective video signal of the video / audio mixed track have a simple integer ratio relationship (2: 1 in this embodiment). Video by
This avoids complication of the recording format due to the fact that the audio mixed track is different from other tracks (video-only track). Without such an integer ratio relationship, it becomes extremely difficult to give a simple regularity as shown in FIG. 16 to the distribution pattern of pixels to each track.

This will be generalized and described. When K video / audio mixed tracks are provided per N tracks, the ratio of the effective video signal data amount per video dedicated track to the effective video signal data amount per video / audio mixed track To A:
If B, then P = A (NK) + BK

By making the effective sample number S per line divisible by, the recording format (particularly the rule of distributing pixels to tracks) is simplified. In the above example, N = 8, K = 1, A = 2, B = 1, and P = 2 × (8−1) + 1 × 1 = 15 can divide S = 1920. As above, N = 8, K
When = 1, all combinations of A and B such that P = A (N−K) + BK divides S are listed in Table 1 below.

[0067]

[Table 1]

In the above table, the color signal (PB or PR
Signal), the effective sample number S per line is 9
It is set to 60. If the combination of A and B is set as shown in the above table, the distribution pattern of pixels to each track is completed within one line.

Similarly, consider the case where the present invention is applied to the D1 format. In this case, N = 4, K = 1, S =
When a combination of A and B is set such that P = A (NK) + BK divides S when 360 (for color signals) is set, the combination is as shown in Table 2 below. However, A ≦ 20.

[0070]

[Table 2]

Similarly, consider the case where the present invention is applied to the D2 format. In this case, N = 4, K = 1, S =
When the combination of A and B is set such that P = A (NK) + BK divides S when set to 768, the combination is as shown in Table 3 below. However, A ≦ 20.

[0072]

[Table 3]

Further, in FIGS. 17A to 17E, N,
An example of a combination of K, A and B is shown. That is, FIG.
17A shows an example in which N = 8, K = 1, A = 2, B = 1, and FIG. 17B shows an example in which N = 3, K = 1, A = 3, B = 2, FIG. 17C shows an example in which N = 4, K = 1, A = 4, B = 3, and FIG. 17D shows N = 5, K = 2, A = 2, B =
In the example shown in FIG. 7 (e), N = 4, K = 2, A =
3, an example in which B = 2 is shown. Next, a second embodiment of the present invention will be described.

FIG. 18 is a schematic block diagram of a reproduction signal processing circuit according to the second embodiment of the present invention. The same parts as those in FIG. 10 are designated by the same reference numerals and the description thereof will be omitted. The outputs of the regenerative amplifiers 901h, 901p, 911a and 911b are connected to each other and are enable-controlled. In the pre-playback mode, the playback head P is set in the rotary drum.
8, P16 signal and audio advance playback head A
The signals from A8 and A16 are switched, multiplexed, and supplied to a common rotary transformer 902h. The enable control signal of each reproduction amplifier (in the enable state at H level) in the preceding reproduction mode is shown in the timing chart of FIG. The figure also shows from which head a signal is supplied to the rotary transformer 902h. However, in order to enable such a circuit configuration, the playback positions of the audio preceding playback head and the normal playback head are mechanically matched so that both signals from both playback heads can be combined. The mounting position of is restricted.

FIG. 20 is a diagram showing the mounting position of the audio advance reproducing head in this embodiment. Truck 1
Reference numeral 801 denotes a video / audio mixed track scanned by the reproducing head P8, and track 1802 denotes a predetermined number of video / audio mixed tracks scanned by the audio preceding reproducing head A8. At this time, heads P8 and A8
By arranging so as to reproduce the audio recording area at the same timing, the reproduction head switching control as shown in FIG. 19 becomes possible. To this end, the reproducing heads P8 and A8 have a positional relationship (distance in the rotating drum scanning direction) as shown in FIG. , The distance h) in the height direction is sufficient. The same applies to the heads P16 and A16. That is, the audio preceding reproducing heads A8 and A16 are connected to the reproducing heads P8 and P1.
6 is a period during which the portion of the audio recording area in the predetermined video / audio mixed track is reproduced, and the audio preceding playback heads A8 and A16 are ahead of the video / audio mixed track by the predetermined time in the video / audio mixed track. The audio recording area is arranged so as to coincide with the reproduction period.

According to the second embodiment, the rotary transformer 912 and the reproduction processing circuit 913, which are required in the first embodiment, are unnecessary, and the number of channels of the rotary transformer and some reproduction processing circuits is further reduced to 1. Channels can be reduced. Next, a third embodiment will be described.

At present, there are several candidates for the high-definition television system other than high-definition television, and the European proposal is one of them. This has a field frequency of 50 Hz and the number of effective lines per frame is 1152 (576 per field). The number of effective samples per line of the Y signal is 1920 or 2048. It is unclear at this time whether only one of these candidates will be decided as a unified standard, and it is highly possible that multiple high-definition television standards will coexist.
Even in such a case, if there is a lot of commonality in the recording format of the digital VTR, there is a great merit not only in the development and manufacturing of the deck but also in the operation and maintenance.

In the above-described first embodiment, the video signal is processed in units of one segment (corresponding to 1/5 field), and the field frequency is 60 Hz, so the segment frequency is 300 Hz. In the European proposal, if processing is performed in units of 6 segments per field (that is, 96 lines per segment), the field frequency is 50 Hz, so the segment frequency is also 300 Hz, the diameter of the rotating drum, the number of revolutions, It is possible to completely standardize the deck part including the number of heads and tape feed speed. If the structure of the synchronization block is the same, more common parts can be added.

Further, since there are so many kinds of languages used in Europe, it is necessary to produce audio in several languages for one video signal. Considering audio suitable for high-definition television, two channels are required for each language to support at least stereo. Therefore, the demand for multi-channel audio is very strong, especially in Europe. By the way, the high-definition television system of the European plan has a smaller total effective information amount of video than the high-definition television of the first embodiment. Therefore, the number of audio channels can be increased without increasing the total recording rate by using the empty area corresponding to this difference.

FIG. 21 shows the contents of the video / audio mixed track in the third embodiment.
01 and 1902 are video recording areas, and an area 190
3, 1904, 1905, 1906 are audio recording areas. Although two audio recording areas are provided in the first embodiment, four audio recording areas are provided in this embodiment, and an 8-channel digital audio signal can be recorded. As a result, the video recording area of the mixed video / audio track is reduced. Even if the number of audio channels is increased as in the third embodiment, the number of audio pre-reproduction heads and the number of rotary transformer channels are not particularly increased.

The present invention is not limited to the above-described embodiment, but various modifications can be made. For example, in each of the above-described embodiments, one track per eight tracks is a video / audio mixed track, but for N and K other than this, K tracks per N tracks may be a video / audio mixed track. Further, the present invention can be applied to a digital VTR which corresponds to a parameter of a high definition television system, for example, the number of samples, or a current standard television system other than the high definition television system. Further, the present invention can be applied not only to the video recording area and the audio recording area, but also to the VTR in which other or additional data recording areas are provided on all or some of the tracks.

[0082]

According to the present invention, the electromagnetic conversion system for audio signals and a part of the signal processor can be shared with those for video signals, the hardware scale can be reduced, and the audio signals can be burst. A rotary head type magnetic recording suitable for a cassette type digital VTR for high definition television, which is robust against errors and which minimizes the increase in redundancy, the number of audio pre-playback heads and the number of rotary transformer channels. A playback device can be provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a rotary drum on which a recording head and a reproducing head used in an embodiment of the present invention are mounted,

FIG. 2 is a track pattern diagram in the first embodiment of the present invention,

FIG. 3 is a diagram showing the contents of a video-only track in FIG.

FIG. 4 is a diagram showing the contents of the mixed video / audio track in FIG.

FIG. 5 is a diagram showing a configuration of a synchronization block in FIGS. 3 and 4;

FIG. 6 is a schematic configuration diagram of a recording signal processing circuit in the embodiment,

7 is an internal configuration diagram of the first recording processing circuit in FIG. 6,

8 is an internal configuration diagram of a second recording processing circuit in FIG. 6,

FIG. 9 is a timing chart at the time of recording in the embodiment,

FIG. 10 is a schematic configuration diagram of a reproduction signal processing circuit in the embodiment,

11 is an internal configuration diagram of a first reproduction processing circuit in FIG. 10,

12 is an internal configuration diagram of a second reproduction processing circuit in FIG. 10,

FIG. 13 is a diagram showing a configuration of an audio error correction matrix in the same embodiment,

FIG. 14 is a diagram showing distribution of audio data to each recording area in the embodiment.

FIG. 15 is a diagram showing a configuration of a video error correction matrix in the embodiment.

FIG. 16 is a diagram showing a distribution pattern of Y signals to tracks in the embodiment,

FIG. 17 is a diagram showing various combinations of trucks,

FIG. 18 is a schematic configuration diagram of a reproduction signal processing circuit according to a second embodiment of the present invention,

FIG. 19 is a timing chart during pre-reproduction in the same embodiment,

FIG. 20 is a diagram showing a mounting position of an audio advance reproducing head in the embodiment,

FIG. 21 shows a video according to the third embodiment of the present invention.
A diagram showing the contents of an audio mixed track,

FIG. 22 is a conventional D1 format digital VTR
Track pattern diagram in

FIG. 23 shows a conventional D2 format digital VTR
Track pattern diagram in

FIG. 24 is a track pattern diagram of a conventional 1-inch open reel high-definition digital VTR.

[Explanation of symbols]

101-107 ... Video dedicated track, 108 ... Video / audio mixed track, 109.110 ... Video recording area, 111, 112 ... Audio recording area, R1-
R16 ... recording head, P1 to P16 ... reproducing head, A
8, A16 ... Audio advance playback head

Claims (4)

[Claims] 1. A rotary head type magnetic recording / reproducing apparatus for recording / reproducing a video signal and an audio signal on / from a plurality of helical tracks formed on the magnetic tape, which are inclined with respect to the longitudinal direction of the magnetic tape. The input means for receiving a signal and an audio signal and the helical track are treated as a plurality of track groups each including N helical tracks, and each track group is used as a video-only track (N-
K) Record only video signals on the helical tracks,
Recording means for recording video signals and audio signals in a mixed manner on K helical tracks used as a video / audio mixed track, and reproducing the video signals and audio signals recorded on each helical track of the track group. A rotary head type magnetic recording / reproducing apparatus comprising a reproducing means. 2. The reproducing means reproduces an audio signal from the mixed video / audio track, and a mixed video / audio which precedes the mixed video / audio track by a predetermined time during a reproduction period by the reproducing head. Switching between at least K audio pre-playback heads arranged to play the audio signal recorded on the track, an audio signal played by said play head and a preceding audio signal played by said audio pre-play head The magnetic recording / reproducing apparatus according to claim 1, further comprising a switching unit for outputting and a rotary transformer to which the signal output from the switching unit is supplied. 3. The audio pre-playback head comprises: a period during which the playback head plays an audio signal from an audio recording area in the video / audio mixed track; 3. The magnetic recording / reproducing apparatus according to claim 2, wherein the magnetic recording / reproducing apparatus is arranged on the rotary drum so that a period during which an audio signal is reproduced from an audio recording area in a video / audio mixed track preceding by a predetermined time coincides. 4. The apparatus according to claim 1, further comprising means for setting the data amount of the effective video signal per one video dedicated track and the data amount of the effective video signal per one video / audio mixed track to an integer ratio. Magnetic recording / reproducing device.