JPS63279682A - Recording system for video signal - Google Patents

Abstract

PURPOSE:To favorably reproduce one sheet of a whole picture by a variable speed mode in a helical scan type VTR performing the azimuth recording of M-tracks/1 field by recording it after rearranging the line sequence that one field is made to be one unit. CONSTITUTION:Assuming the number of M-pieces of the tracks, allocated to the recording area of one field, to be (m) (m=1, 2...M), a video signal of one field N-lines shown by a time series signal Sn (n=1, 2...N) is rearranged at every field into the line sequence of nm= m+(n-1).M and is recorded in the track of the number (m) sequentially. For instance, when M=2 and it is recorded on two tracks of 262 lines at every one field, the video signal of 131 lines portion of the odd line number (2nm-1) is recorded on the tracks (TR1, TR3) of the odd track number and the video signal of 131 lines portion of the even line number (2nm) is recorded on the tracks (TR2, TR4) of the even track number. Thus, the signal of one field N-lines can be uniformly distributed and recorded on the tracks of M-pieces.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording method in a helical scan type video tape recorder, and in particular, the present invention relates to a video signal recording method in a helical scan type video tape recorder. The present invention relates to a recording method for recording and reproducing.

[Summary of the invention]

In a helical scan type video tape recorder, when recording and reproducing a video signal by allocating a plurality of tracks to one field of recording area, the present invention provides M (M≧2) tracks allocated to one field of recording area. As the track number m (m=1.2...M) of the track,
A video signal of one field and N lines indicated by a time series signal Sn (n=1.2...N) is converted into nm=m+(n-
1) By rearranging each field in line order M and sequentially recording on each track with track number m, a reproduced video signal with good image quality that does not cause image loss during reproduction operation in variable speed mode is produced. This is to make it possible to obtain the following.

[Conventional technology]

-i, a helical scan type video tape recorder (
Hereinafter, it will simply be referred to as a VTR. ), one track is assigned as a recording area for one field, and one track/one field azimuth recording is performed in which adjacent tracks have different recording azimuths.

For example, an NTSC system that records and plays an interlaced 525-line video signal for l frames configured as shown in FIG. 6 in the first and second fields.
In a helical scan type VTR, two video heads with different azimuth angles are installed 180 inches opposite each other on a rotating drum that rotates at a frame frequency (30 Hz), and are switched at a field frequency (60 Hz) to produce magnetic signals as shown in Figure 7. By scanning the tracks TR, ,TR, on the tape 1, the video signal of the first field from the 1st line to the 262nd line is recorded on the first track TR, which is scanned by one of the video heads. The video signal of the second field from the 263rd line to the 525th line is recorded on the second track TR scanned by one video head.

In addition, in a helical scan type VTR, the recording wavelength is S/
Due to the constraints on N, the drum rotation speed is multiplied by an integer CM of the frame frequency, and the recording area of one field is M.
Tracks of a book may be assigned to perform azimuth recording of M tracks/1 field.

For example, the above-mentioned NTSC helical scan VTR
At the same time, the rotating drum is rotated at a frequency twice the frame frequency (60 Hz), and the video head facing 180 degrees is rotated at a frequency twice the field frequency (120 Hz).
Hz), as shown in Figure 8,
Two tracks are allocated as one field recording area on the magnetic tape 2, the video signal of each field is divided into two, and the first line is recorded on the first track TR scanned by one video head. from the 131st
Lines 132 to 262 are recorded on the second track TR scanned by the other video head, and lines 263 to 263 are recorded on the third track TR3 scanned by one video head. Lines up to the 393rd line are recorded, and lines from the 394th line to the 525th line are recorded on the fourth track TR scanned by the other video head.

[Problem that the invention seeks to solve]

By the way, in the NTSC video signal of 525 lines per frame, each video signal of the first field and the second field constituting one frame is shown in (A) and (B) in Fig. 9.
), each form a single image with field correlation, but the helical scan type VT
In R, as mentioned above, one field of recording area is M.
If M tracks/1 field of azimuth recording is performed with the tracks of a book being tracked, for example, if M = 2, one image shown by one field of video signal will be divided into two vertically. Since recording will be performed on two tracks with different azimuth angles, when performing playback operations in variable speed modes such as still playback, slow motion playback, or quick motion playback, the data will be recorded on two tracks with opposite azimuth angles. The recorded video signal cannot be played back, and the upper or lower half of the image is missing, as shown in Figure 9 (C).
There is a problem in that the entire image cannot be reproduced.

Therefore, in view of the above-mentioned conventional problems, the present invention has been developed by
The present invention provides a video signal recording method that enables reproduction of a high-quality video signal representing one entire image in a variable speed mode in a helical scan VTR that performs azimuth recording of one track/one field.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention records video signals by allocating a plurality of tracks to one field of recording area in a helical scan type video tape recorder. When performing playback, the track number of the M zero track assigned to the recording area of the L field is set to m (m
= 1.2...M), the time series signal Sn (n-1
, 2...N) is rearranged field by field into a line order of nm=m+ (n-1) ・M, and each track number m
The feature is that recording is performed sequentially on the tracks.

[Effect]

In the video signal recording method according to the present invention, by rearranging the line order with one field as one unit, the video signal of one field and N lines is evenly distributed and recorded on M tracks line by line. For example, when recording on two tracks of 262 lines in one field with M=2, as shown in FIG.
-1) 131 lines of video signals are recorded on odd track numbers (TR,,TR,), and 131 lines of even line numbers (2n) are recorded on even track numbers (TR,, TR,). T.R.

Record in TR, ).

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In the block diagram of FIG. 2 showing the configuration of a recording system of a helical scan type VTR that performs two-track/one-field recording by applying the present invention, a signal input terminal 10
is supplied with an NTSC video signal (SIN),
This input video signal (S IN) is sent to the signal input terminal 1.
0 to the synchronous separation circuit 11 and the analog/digital (A
/D) is supplied to the conversion circuit 21.

The synchronization separation circuit 11 separates the synchronization signal superimposed on the input video signal (SIN) and outputs it to the clock generation circuit 11.
2 and is supplied to the timing generation circuit 13. The clock generation circuit 12 generates a 4fsc sampling clock, a memory access clock, an address clock, etc. synchronized with the synchronization signal. In addition, the above fsc is NTSC
This is the subcarrier frequency in the system. The sampling clock obtained by the clock generation circuit 12 is supplied to an analog-to-digital (A/D) conversion circuit 21 and a digital-to-analog (D/A) conversion circuit 24, and the memory access clock is supplied to two field memories. 22A,
22B, and the address clock is further supplied to the write address counter 14 and the read address counter 1.
5. In addition, the timing generation circuit 1
3 forms a write/read control signal (W/R), a reset signal, a switching control signal (S+, St), etc. based on the synchronization signal. The write/read control signal (W
/R) is each field memory 22A.

22B, the reset signal is also supplied to the write address counter 14 and the read address counter 15, and the switching control signal (s, , St)
are supplied to signal selection circuits 23 and 27.

Further, the A/D conversion circuit 21 has the signal input terminal l.
As shown in FIG. 3, one frame of 525 lines of NTSC input video signal (SIN) is supplied from the clock generation circuit 12 through the clock generator 12. 4fs
The input video signal (SIN) is sampled and quantized by a sampling clock of c to form video data. The video data obtained by the A/D conversion circuit 21 is stored in the first and second field memories 22A.

22B.

the first and second field memories 22A;

22B each has a storage capacity for one field, and when video data is written to one,
The writing/reading control signal (W/R) supplied from the timing generating circuit 13 alternately switches between a writing operation and a reading operation for each field period so that video data is read from the other side. The storage location of the video data is designated in order by the write address data supplied from the S write address counter 14, and as shown in FIG. 3, the video data of the first field is stored in the first field memo I722. A and the second field data is written to the second field.
is written into the field memory 22B. Further, the first and second field memories 22A and 22B are
As shown in FIG. 3, odd-numbered lines of video data are sequentially read out in the first half of one field period from memory locations sequentially specified by read address data supplied from the read address counter 15, and In the latter half of the field period, even-numbered lines of video data are read out in order.

That is, in this recording system, the line order of video data is rearranged field by field by the first and second field memories 22A and 22B.

Then, the first and second field memos 1722
The video data read out from A and 22B and whose line order has been rearranged is sent to digital/analog (D
/A) is supplied to the conversion circuit 24, and the D/A conversion circuit 24
It will be converted to analog. The video signal whose line order has been rearranged obtained by the D/A conversion circuit 24 is supplied to a recording amplifier circuit 26 via a modulation circuit 25, and from this recording amplifier circuit 26 via a head selection circuit 27, a pair of It is supplied to video heads 28A and 28B. The head selection circuit 27 is controlled by the switching control signal (S2) supplied from the timing generation circuit 13 to alternately select the pair of video heads 28A and 28B every 1/2 field period. As shown in FIG. 3, the video signals of odd lines are supplied as recording signals to one video head 28A, and the video signals of even lines are supplied as recording signals to the other video head 28B.

Here, the head motor 31 that rotates the pair of video heads 28A and 28B is servoed by a servo circuit 32 so that it rotates at 60 Hz, which is twice the frame frequency (30 Hz) in the NTSC system.

The pair of video heads 28A and 28B diagonally scan a magnetic tape 30 that is run at a constant speed by a tape running system (not shown), and record a video signal in the 2-track/1-field recording format shown in FIG. Azimuth recording is performed, and video signals for 131 lines with odd line numbers (2 nm-1) are recorded on tracks with odd track numbers (T
R.

TR, ), and even line number (2 nm) 131
A line worth of video signals is recorded on even-numbered tracks (TR, , TR,).

Furthermore, a reproduction system for reproducing the video signal recorded on the magnetic tape 30 by the recording system is constructed by removing the modulation circuit 25 and the recording amplification circuit 26 in the recording system, as shown in the block diagram of FIG. A signal output terminal 50 is provided on the output side of the A conversion circuit 24, and a head selection circuit 27 is provided.
A demodulation circuit 42 is connected to the movable end of the demodulation circuit 42 via a regenerative amplifier circuit 41, and the output end of the demodulation circuit 42 is connected to the synchronization separation circuit 11 and the A/D conversion circuit 21.

In this playback system, a pair of video heads 28A and 28B sequentially trace each track on the magnetic tape 30 on which video signals are azimuthally recorded in the 2-track/1-field recording format as described above. As shown in Figure 5, the odd numbered tracks (TR,, TR
3), a playback signal of an odd line video signal is obtained every 1/2 field period, and an even number track (TRz
, TR, ), reproduction signals of even-numbered lines of video signals are obtained every 1/2 field period.

Reproduction signals obtained alternately every 1/2 field period by the pair of video radars 28A and 28B are continuously taken out by the head selection circuit 27 and sent to the reproduction amplifier circuit 41.
The signal is supplied from the regenerative amplifier circuit 41 to the synchronization separation circuit 11 and the A/D conversion circuit 21 via the demodulation circuit 42.

The A/D conversion circuit 21 converts the reproduced video signal supplied from the demodulation circuit 42 into the clock generation circuit 12.
Digitalization is performed based on a 4fsc sampling clock supplied from From the A/D conversion circuit 21,
Odd-numbered lines of video data are obtained in the first half of one field period, and even-numbered lines of video data are obtained in the second half of one field period. The video data obtained by the A/D conversion circuit 21 is transferred to the first and second field memories 2 in the same line order as shown in FIG.
Data is written alternately in fields 2A and 22B in field units.

In this reproduction system, when reading the video data written in the first and second field memories 22A and 22B, the line order is rearranged in field units, and the first and second field memories 22A and 22B are read out.
By converting the video data read from 2A and 22B into analog data in the D/A conversion circuit 24, a reproduced video signal with a continuous line order is outputted from the signal output terminal 50 as shown in FIG. In addition, with the above regeneration system,
For example, when performing variable speed playback such as 9x speed playback as indicated by the arrow in FIG. , the other video head 22
A reproduced video signal of each field configured as shown in FIG. 5 can be obtained at the signal output terminal 50 using the reproduced signal according to B, that is, the video signal of odd lines in which only the video signals of even lines are missing.

In the above-described embodiment, the present invention was applied to a helical scan type VTR to perform analog signal recording of 2 tracks/1 field, but the present invention is not limited to the above-mentioned embodiment. The present invention can be applied to a helical scan VTR that allocates M tracks as field recording areas and records M tracks/1 field of analog or digital signals. That is, M (M≧2) tracks with track numbers indicated by m (m=1.2...M) are allocated as one field recording area in a helical scan type VTR, and the time series signal Sn (n=1.2...N) of one field N lines of video signal is nm,=m+ (n-
1) - The analog or digital signals may be recorded in order on each track number m by rearranging each field in line order M.

〔Effect of the invention〕

In the video signal recording method according to the present invention, by rearranging the line order with one field as one unit, the video signal of one field and N lines is evenly distributed and recorded on M tracks line by line. Even if the video signal of a particular track is lost, the entire image shown by the video signal of 1 field can be reproduced. Accordingly, it is possible to reproduce a high-quality video signal representing the entire image.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a recording format of a helical scan VTR to which the present invention is applied, and FIG. 2 is a recording system of a helical scan VTR that records video signals in the recording format shown in FIG. 1 above. 3 is a timing chart showing the operation of the recording system, FIG. 4 is a block diagram showing the structure of the playback system of the helical scan VTR, and FIG. 5 is a block diagram showing the playback system of the helical scan type VTR. It is a timing chart showing the operation. Fig. 6 is a schematic diagram showing the configuration of a video signal in the NTSC system, Fig. 7 is a schematic diagram showing the recording format of a general helical scan type VTR that performs one track/one field recording operation, and Fig. 8 is a schematic diagram showing the recording format of a general helical scan type VTR that performs one track/one field recording operation. A schematic diagram showing the recording format of a conventional helical scan type VTR that performs a track/one field recording operation, and FIG. 9 shows a reproduced image by a conventional helical scan type VTR that performs a two track/l field recording operation. It is a schematic diagram. 10... Signal input terminal 21... A/D conversion circuit 22A, 22B... Field memory 24...D
/A conversion circuit 28A, 28B...video head 30...magnetic tape TR, -TR,...track

Claims (1)

[Claims] 1 in a helical scan type video tape recorder
As the recording area of the field, the track number is m (m=
Allocate M (M≧2) tracks indicated by 1, 2...M), and 1 indicated by time series signal Sn (n=1, 2...N).
The video signal of field N lines is n_m=m+(n-
1) A video signal recording method characterized in that each field is rearranged into a line order of .M and sequentially recorded on a track having a track number m.