JPS59100675A - Multiplex recording system and multiplex recording and reproducing system - Google Patents

Abstract

PURPOSE:To prevent the generation of moire by recording and reproducing an audio signal by an exclusive rotary audio head. CONSTITUTION:In forming a track T2 on a tape 6, after an audio signal is recorded by an audio head 3, a video signal is recorded on the same track T2 by being superimposed on the audio signal by a video head 11. In forming the track T4, the signal is recorded similarly. The video signal is recorded with azimuth on adjacent tracks T1-T4- at each field by video heads 11, 12, the audio signal for one frame's share is recorded with azimuth on tracks T2, T4 at each other track by the audio head 3 while taking video signal tracks T1, T3- as guard bands with time compression on one track.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multiplex recording system and a multiplex recording/playback system, and in particular, the present invention relates to a multiplex recording system and a multiplex recording/reproducing system, and in particular, the L channel and R channel audio signals are recorded in the first half of the same track as the video signal using one rotating audio head dedicated to the audio signals. It is an object of the present invention to provide a multiplex recording system and a multiplex recording/reproducing system that can record and reproduce audio signals of the L channel and the R channel using one carrier frequency.

Helical scanning magnetic recording/reproducing device (VTR)
), a plurality of, for example, two, rotating heads are attached to a rotating body such as a rotating drum at equal angular intervals, and a magnetic tape is attached to and wound around the rotating body over an angular range of, for example, more than 180°. The video signal is recorded on the magnetic tape by a rotating head, the audio signal is recorded by a fixed head installed in the middle of the magnetic tape running path, and during playback, the video signal is played back by the rotating head, and the audio signal is transferred to the fixed head. It is a well-known practice to reproduce audio signals.

On the other hand, the recording and reproducing time of VTRs has tended to become longer in recent years, and the running speed of magnetic tapes has accordingly tended to decrease. Furthermore, it is desired that audio signals be reproduced with very high quality. However, audio signals are recorded on magnetic tape using a fixed head.

Since the relative linear velocity between the tape and the head is low during playback, if the running speed of the magnetic tape is slowed down, the frequency characteristics of the audio signal will deteriorate more significantly than the frequency characteristics of the video signal recorded and played back by the rotating head. This made it impossible to record and play back high-quality audio signals.

Therefore, conventionally, a method has been proposed in which the audio signal is converted into a predetermined signal format and superimposed on the video signal, and this superimposed signal is recorded on a magnetic tape by a rotary head for recording and reproducing the video signal, and this is then played back. There is. According to this recording and reproducing method, audio signals are recorded and reproduced by a rotating head on a magnetic tape with a high relative linear velocity between the tape and the head, so even when the magnetic tape runs at a slow speed, Compared to recording and reproducing audio signals using a fixed head, which requires slowing down the running speed of magnetic tape, it records and plays back audio signals with much higher quality.
Can be played.

However, in the recording and reproducing method proposed above, the audio signal is at least frequency modulated and then superimposed on a video signal consisting of, for example, a frequency modulated luminance signal and a low frequency converted chromaticity signal, and this superimposed signal is transmitted to the same rotating head. Since recording and playback are performed simultaneously, there is a problem in that beats occur between carrier frequencies, and these beats cause interference (moiré) on the playback screen.

The present invention solves the above problems, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of the multiplex recording system according to the present invention. In the figure, the video heads 11 r 12E, j are attached to the rotating drum 2 by 180° as shown in FIG.
They are placed facing each other. Reference numeral 3 denotes an audio head, which is provided on the drum 2 at an angle of, for example, 55° with respect to the video head 12, and at a position higher than the video head 11 + Ill by, for example, 18 μm. The azimuth angle of the video head 11 is, for example, -Po, that of the video head 12 is, for example, +6 degrees, and that of the audio head 3 is, for example, -3 degrees.The azimuth angles of these three heads are mutually different from those of all other heads. It is set differently for that.

In FIG. 1, a color video signal inputted to a terminal 4 is subjected to low frequency conversion of a chromaticity signal C and a luminance signal Y in a video signal recording circuit 5 as shown in FIG.
is FM modulated and supplied to the video 6-rad 11 r 12, and azimuthally recorded on the magnetic tape 6 for each track.

In FIG. 1, switches SWa, SWt and switches f SWd, SWe are shown in FIG.
), (E'l, As shown in n, the switching timing is alternately changed every two fields in response to the drum pulse from drum 2 (FIG. 4 (g)), partially superimposed on the beginning period of the first field. 7 is a clock pulse generator which is supplied with a horizontal synchronizing signal (or color burst signal, drum pulse) and generates, for example, the light clock pulses W and CK of frequency f and their respective terminals. It is configured to output read clock pulses R and CK with a frequency of 4.4f, which is 4.4 times higher.As shown in Fig. 1, the switch SWd is connected to the terminal ■, and the switch SWe is connected to the terminal ■. and bucket-brigate device (hereinafter referred to as BBD) BBD, , BBD
3 is in write mode by being supplied with a light clock pulse;
It is assumed that BBD2 and BBD are supplied with a read clock pulse and set in read mode. On the other hand, it is assumed that the switch SWa is connected to the terminal (2) and the switch SWb is connected to the terminal (2).

Here, in the first field, the L channel audio signal input to the terminal 8L has unnecessary frequency components removed by the low-pass filter 9L, and is then written to BBDl via the switch SWa, while inputting to the terminal 8R. The incoming R-channel audio signal is passed through the low-pass filter 9□ to the BB
Written to D3.

On the other hand, a switching signal having an H level is formed during this period in synchronization with the connection of the terminals ■'\ of the switches SWa and SWb and the fall of the drum pulse.
is configured to be connected alternately to terminals ■ and ■ only during the H level period of this switching signal.In the second field, switch SWc is not connected to either terminal, so no audio signal is taken out and the As shown in FIG. 5, only a video signal is recorded as a track 'rl (broken line) on the magnetic tape 6 (the running direction is indicated by an arrow ■) by a video head 12 (the tracing direction of the head is indicated by an arrow ＠＼
During this second field, switches SWa, SW
d remains connected to terminal ■, switches SWb and SWe remain connected to terminal ■, and the L channel audio signal is connected to B.
BDl and R channel audio signals continue to be written to BBD3, respectively.

In the next first field, switch SWa.

8Wd is terminal ■, switch swb, SWe is terminal ■
can be switched to respectively. As a result, the L channel audio signal written to BBD1 in the previous frame is read out at 4.4 times the writing speed, while the R channel audio signal written to BBD3 in the previous frame is read out at a speed of 4.4 times the writing speed. Reads at 4.4 times the speed, switch 8W
is supplied to the BBD1 from where it is read out subsequent to reading out the L channel audio signal. That is, in the first half of the next first field, the L written in the previous frame is
The channel audio signal is time-compressed and read out as shown by the solid line in FIG. Following 9
It is compressed for one hour and read out.

B BD, the read L channel audio signal and R channel audio signal are passed through the low pass filter 1.
After unnecessary frequency components are removed at 0, the FM modulator 11
As shown in FIG. 5, the frequency of the chromaticity signal C of the video signal is higher than that of the chromaticity signal C of the video signal. is recorded on the track Tz (solid line).

At the same time, in the first field and the second field, the L channel audio signal is sent to the switch SW.
b to BBD2, while the R channel audio signal is written to BBD4. These signals are further time-compressed and read out at a speed 4.4 times the writing speed in the next frame, and recorded on the tape 6 as shown in track T4 in FIG.

When forming the track T2, after the audio signal is recorded, the same track T2 is recorded in the video head 1K.
The video signal is superimposed on the audio signal and recorded (dashed line). When forming the track T4, the video head 11 records the video signal superimposed on the audio signal in the same manner.

In this way, the video signal is transferred to the video nodes 11, 12.
The audio signals of the L channel and R channel for one frame are recorded azimuthally on adjacent tracks for each field (tracks Tl, T2, T3...), and the audio signals of the L channel and R channel for one frame are recorded every other track by the audio head 3. The video signal tracks 'T1+T31...) are time-compressed into one track as a guard band, and are recorded azimuthally with respect to the video signal (tracks T2, T4,...).

Note that in this embodiment, the BBD is read out with a slight delay from the rise of the drum pulse, and is read out after writing is completely completed, so the audio signal is read out from the track T2.
The lower part is not formed. In this case, the structure may be such that reading is performed before the writing is completed. In this case, recording can be performed without forming the lower portion, but the structure becomes more complicated than the circuit shown in the first diagram.

Also, the reason why the read clock pulses R and CK are approximately four times as large as the write clock pulses W and CK is because one frame's worth of L channel and R channel audio signals are sequentially arranged in one field's worth of tracks for each channel. This is because the data is read out in a divided manner, and in this embodiment, the reason why it is increased by 4.4 is because the beginning of each field is recorded with a portion overlapping.

FIG. 6 shows a block system diagram of a reproducing system of an embodiment of the multiplex recording/reproducing method according to the present invention, in which parts having the same functions as those in FIG. 1 are given the same numbers.

The video signal reproduced by the video head IT+ 12 is converted into the chromaticity signal to the original frequency by a well-known technique in the video signal reproduction circuit 12, and the luminance signal is FM demodulated.
It is returned to the original video signal and taken out from the output terminal 13.

On the other hand, the clock pulse generator 7 has a frequency of 4.4 during reproduction.
f (same as read clock system R and CK during recording)
It is configured to output read clock pulses R, CK (same as the write clock pulses W, CK, and the read clock pulses R, CK).

During the first H level period of the drum pulse, when the switch SWi is connected to the terminal, the switch 8Wj is connected to the terminal ■, and the interlocking switches SWf and SWg are connected to the terminal ■, respectively,
For example, track T2 played by the audio head 3
The L-channel audio signal is amplified by an amplifier 14, then FM demodulated by an FM demodulator 15, and unnecessary frequency components are removed by a low-pass filter 16. The signal extracted from the low-pass filter 16 is written to the BBD3 at a frequency of 4.4f, and is subsequently extracted from there to the BBDl.
Subsequently, the R channel audio signal is played back and written to the BBD 3 at a frequency of 4.4f (as shown in FIG. 7).

During the first L level period of the drum pulse, when switch 8Wi is connected to terminal ■, switch SWj is connected to its it terminal ■, and switches SWf and SWg are connected to terminal B.
BD1 to BBD are in read mode.

As a result, Lchar 1 written to BBDl for the above period
3. On the other hand, in the latter half of the above period, the Rcha written in the BBD is output.

In the H level period following the drum pulse, switch 8
Wf and SWg are connected to the terminal ■, the switch 8Wi is connected to the terminal ■, and the switch SWj is connected to the terminal ■.

During this period, the L channel audio signal and the R channel audio signal are continuously read out from the BBDI and BBDs. Tsumashi, time compressed to 2 in 1 track
The audio signal recorded for one field is time-expanded and read out over one frame.

The read L channel audio signal is sent to switch SW.
After unnecessary frequency components are removed by a low-pass filter 17L via f, the R channel audio signal is extracted from an output terminal 18L, while the R channel audio signal is extracted from a terminal 18□ via a low-pass filter 178 via a switch SWg. .

During this period, BBD2 and BBD4 are each in the write mode, and the L channel O-1 of track T4 in FIG.
4- The audio signal is written to BBD4 and extracted from there and written to BBD2, followed by the R channel audio signal being written to BBD4. BBD2. The audio signal written to the BBD 4 is time-expanded and read out in the next frame in the same manner as in the above case.

When the audio signal of the track 'P2+'r4 is reproduced by the audio head 3, the video head 11 traces the track 'v2+'I'4 and reproduces the video signal of that field.

Furthermore, when audio signals are played back, the beginning of each field is overlapped, so even if there is jitter in the rotating drum, noise when switching between fields can be reduced. It is possible to supplement and reproduce unrecorded signals.

Further, although the above embodiment has a configuration in which an analog audio signal is time-compressed and expanded using a BBD, the present invention is not limited to this, and other analog delay elements such as a CCD may be used, or a digital code may be used. It is also possible to use a configuration in which the encoded audio signal is time-compressed and expanded using a RAM or the like.

Furthermore, when switching during the overlapping period, it is recommended that the fall and rise of the audio signal to be switched be made at a relatively gentle slope angle to create a fade-out and fade-in configuration, to reduce switching noise, especially in the high range. The reduction can be measured.

As mentioned above, according to the multiplex recording method and multiplex recording/playback method of the present invention, since audio signals are recorded and played back using a dedicated rotating audio head, the quality is higher than when recording and playing back using a fixed audio head. Can be recorded, played back,
Furthermore, compared to recording and reproducing a superimposed video signal and audio signal using the same rotary head, there is no possibility of beats occurring between carrier frequencies, and this beat does not interfere with the playback screen. Also, since audio signals are recorded every other track with a video track in between, crosstalk between audio signals can be reduced, and since there is only one rotating audio head,
The rotary transformer for the audio head only needs to be for one channel, so there is no need for sensitivity adjustment or adjustment of the mounting position compared to a rotary transformer that requires two. Since the signal is time-compressed and recorded on one track, the carrier frequency of the audio signal only needs to be one.
It has the advantage that only one M modulator and one FM post-adjuster in the reproduction system are required, and the circuit can be easily constructed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the recording method of the present invention.
Figure 2 is a schematic diagram showing the positional relationship between the video head and audio head used in the recording method of the present invention, Figure 3 is the frequency spectrum of the video signal and audio signal recorded on the magnetic tape by the recording method of the present invention, and Figure 4. (g) ~0 is a timing chart for explaining the operation of the recording method of the present invention, No. 5
The figure shows a track pattern recorded on a magnetic tape using the recording method of the present invention, FIG. 6 is a block diagram of an embodiment of the reproducing method of the present invention, and FIG.
17- This is a timing chart for explaining the operation. 11 + 12...Video head, 3...Audio head, 4...Video signal input terminal, 6...Magnetic tape, 7...Clock pulse generator, 8L...L channel audio signal input Terminal, 8FL...R channel audio signal input terminal, 11...FM modulator, 13...video signal output terminal, 15...FM demodulator, 18. ...L channel media signal output terminal,
18□...R channel audio output terminal, SWa
-SWg, SWi, SWj --- Switch, BBD1 to BBD, ... Packet brigade device, Tl * T2 + 'r3# ... Track. 18- -4 cane 1-) Zeichino, +-++'' ゝ/ +
+□ one

Claims (4)

[Claims] (1) The L-channel audio signal and the R-channel audio signal of the audio signal corresponding to one frame of the video signal are time-compressed, and one rotating audio head placed on a rotating drum is used to generate magnetic deso signals every other track. One of the two rotating video heads disposed on the rotating drum at a different azimuth angle from the front audio head of the book track produces one frame superimposed on the track formed by the rotating audio head. Multiplex recording characterized in that one field's worth of video signals is recorded, and the other rotating video head records one field's worth of video signals independently between tracks formed by the rotary audio head. method. (2) The frequency of the audio signal recorded on the magnetic tape is lower than the frequency of the frequency-modulated luminance signal of the video signal and higher than the frequency of the low-pass converted chromaticity signal. The multiplex recording method described in scope 1. (3) The L-channel audio signal and the R-channel audio signal of the audio signal corresponding to one frame of the video signal are time-compressed, and one rotary audio head placed on a rotary drum records every other track on the magnetic tape. One of the two rotating video heads disposed on the rotating drum at a different azimuth angle from the front audio head of the book track produces one frame superimposed on the track formed by the rotating audio head. The video signal for one field is recorded, and the video signal for one field is recorded independently between the tracks formed by the other rotating video head. Each channel audio signal is played back from the magnetic tape by the rotating audio head, and each channel is expanded in time to be simultaneously extracted as an audio signal corresponding to one original frame, while a video signal is played back from the magnetic tape by the rotating video head. A multiplex recording/playback method characterized by: (4) A claim characterized in that the frequency of the audio signal recorded on the magnetic tape is lower than the frequency of the frequency-modulated luminance signal of the video signal and higher than the frequency of the low-pass converted chromaticity signal. The multiplex recording and reproducing method described in item 3.