JPS62177702A - Post-recording method for recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a signal on only one channel by erasing simultaneously two channels with one rotary erasing head which precedes a recording head and follows a preceding reproducing head when two rotary magnetic heads are used to record time base-compressed sound signals of two channels. CONSTITUTION:Inputted sound signals CH1 and CH2 of two channels are converted to digital signals by A/D conversion circuits 1a and 1b and are inputted to compressing circuits 3a and 3b through switching circuits 2a and 2b. These signals have the time base compressed in one-field units by circuits 3a and 3b and are sent to encoding circuits 4a and 4b and are subjected to error detection for reproducing and error correction and are applied to modulation circuits 5a and 5b and are modulated into signals most suitable for reproducing. Thereafter, the signal CH1 is inputted to a switching circuit 6a for switching between the signal CH1 and a Y signal of a video signal, and the signal CH2 is inputted to a switching circuit 6b for switching between the signal CH2 and a C signal of the video signal, and rotary magnetic heads 8a and 8b are used to record signals on the magnetic tape by recording amplifies 7a and 7b. Thus, the signal CH1 is recorded on an extension of the Y signal, and the signal CH2 is recorded on an extension of the C signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an after-recording method for a recording/reproducing apparatus such as a video tape recorder (hereinafter referred to as a VTR).

Conventional technology In commercial VTRs, in order to improve image quality, the video signal is divided into a luminance signal and a carrier color signal, and each is recorded on two trays on a magnetic tape using separate rotating magnetic heads. A method was thought of. FIG. 6 shows the arrangement of the rotating magnetic head in this case, and the Y signal is RYA.
, RYB, and C signals are recorded using RcA and RcB rotating magnetic heads. FIG. 4 shows the format of recording signals on a magnetic tape. Y signals and C signals are recorded alternately, and two tracks of the Y signal and C signal constitute one field of the video signal. When erasing a video signal recorded using the method described above, it is sufficient to erase it field by field.
The Y and C signals are simultaneously erased by one rotating erase head with a track width that includes the signal track and the C signal track. A layout diagram of the rotary erasing heads EA and EB is shown in FIG.

On the other hand, in order to improve the quality of the audio signal, the digitized audio signal corresponding to the period of one field is compressed in time and recorded on the same track following the video signal between one field. A method was thought of. As shown in FIG. 4, by using the above-mentioned rotating magnetic head to record video signals on a portion where a magnetic tape is wound more than 18 degrees on a cylinder equipped with a rotating magnetic head for recording video signals, as shown in FIG.
A digital audio signal of channel 1 (cHl) is recorded on the extension of the Y signal track, and a digital audio signal of channel 2 (CH2) is recorded on the extension of the C signal track. Therefore, if the erasing current is applied to the rotary erasing head during the period shown in FIG. 4A, one field of video signal can be erased, and if the erasing current is applied during the period shown in FIG. 4B, the audio for one field can be erased. Signals can be erased.

Problems to be Solved by the Invention However, in the above-mentioned conventional recording method, when performing after-recording of audio signals, CH1.

The audio signal of CH2 is deleted at the same time, making it impossible to perform after-recording on only one channel.

In view of this point, the present invention provides C
It is an object of the present invention to provide a means for after-recording only one channel in a VTR that simultaneously erases audio signals of H1 and CH2.

Means for Solving the Problem The present invention precedes two rotating recording heads for recording two channels of digital audio signals, and further precedes one rotating erasing head for simultaneously erasing two channels of audio signals. two advance playback rotary heads mounted to scan different tracks of the magnetic tape, the advance playback head reads the digital audio signal before the signal on the magnetic tape is erased by the rotary erase head; 9. This method enables after-recording of only one channel by switching the channel for after-recording with a newly recorded signal and re-recording it on the original track using the rotary recording head.

For production The present invention uses the above-described configuration to control CH1 of an audio signal.

There is no need to separate the rotary erasing head for each CH2.
It is possible to perform after-recording of only one of the audio signals, CH1 or CH2.

Embodiment FIG. 1 shows the configuration of an audio signal recording and reproducing circuit for realizing an after-recording method of a recording and reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, 1a and 1b are AD conversion circuits that convert audio signals into digital audio signals. 2a.

2b is a switching circuit that switches between a newly recorded audio signal and an audio signal obtained by the preceding playback head at the time of after-recording. Compression circuits 3a and 3b perform time axis compression. +a and +b are encoded by encoding circuits so that error detection and error correction can be performed during reproduction. 5a and 5b are modulation circuits that convert the signals into signals suitable for magnetic recording. 6a, 6b
The switching circuit switches between the audio digital signal and the video signal. 7a and 7b are recording amplifiers, and 8a and 8b are rotary magnetic heads for recording. Reference numerals 9a and 9b denote advance reproduction rotary magnetic heads which are attached so as to scan tracks preceding the tracks scanned by the recording heads 8a and 8b. IQa, 10b is a reproduction amplifier, 11a, 11b
is a demodulation circuit, 12a.

12b is an error correction circuit that performs error detection and error correction. Decompression circuits 13a and 13b perform time axis expansion.

14a and 14b are DA conversion circuits that convert digital audio signals into analog audio signals.

The operation of the audio signal recording/reproducing circuit of this embodiment configured as described above will be described below.

In normal recording, the input audio signal CH
1 and CH2 are AD conversion circuits 1a, respectively.

The analog signal is converted into a digital signal at 1b, passes through switching circuits 2a and 2b, and then is sent to a compression circuit 3a.

3b. In the compression circuit 3, time axis compression is performed in units of one field, and in the encoding circuit 4a.

4b. The encoding circuits 4a and 4b perform a code configuration that allows error detection and error correction during reproduction, and input the code to the modulation circuits sa and sb. Modulation circuit 6a,
In sb, the signal is converted into a signal that is optimal for recording and reproducing on a magnetic tape, and CH1 is input to a switching circuit 6a for switching between the video signal Y signal and CH2 is input into a switching circuit 6b for switching between the video signal and C signal.

Then, the recording amplifiers 7a and 7b perform recording on the magnetic tape using the respective rotary magnetic heads aa and sb. As a result, as shown in FIG. 4, CH1 is recorded on the extension line of the Y signal of the video signal, and CH2 is recorded on the extension line of the C signal of the video signal.

Figure 2(a) shows a timing chart during recording.
One field of audio signals A1a, A1b, A1c.

...and A2a, A2b, A2o, ...
・ is time axis compressed, encoded, and modulated Rla"'1b, R
1c “”” and R2O.

It is recorded on the magnetic tape at the timing of R2b, R2O, . . . .

During reproduction (pre-reproduction rotating magnetic heads 9a, 9
A signal is read from the magnetic tape using the magnetic tape, amplified by reproduction amplifiers 10a and 10b, and input to a demodulation circuit 118.degree. 11b. The digital signals demodulated by the demodulation circuits 11a and 11b are input to error correction circuits 12a and 12b, where error detection and error correction are performed. The corrected digital signal is expanded to the original time axis by expansion circuits 13a and 13b, and converted into an analog audio signal by DA conversion circuits 14a and 14b and output.

2) shows a timing chart during reproduction, the reproduction signal P1 obtained from the preceding reproduction rotary magnetic heads 9a and 9b
a, P1b, ... and P2a, P2b, ...
... after demodulation and error correction, A1a/
, A1b', ... and A2a', A2b', ...
・・・It is expanded into parts.

Next, an explanation will be given of the operation when after-recording at least one channel of the two-channel audio signal recorded by the method described above.

FIG. 3 shows a timing chart for after-recording only CH2, and the advance reproduction rotating magnetic disks 9a and 9b are the recording disks 8a.

8b is attached so as to scan a track preceding the track being scanned. That is, the recording head 8a
, sb scan signals at the timings of Rlb and RlC in FIG.
It will be played at the timing of 9P1o. Third
The signal reproduced at the timing of Plb and Plc in the figure is demodulated by the demodulation circuit 11a in FIG.
3a. The signal input to the expansion circuit 13a is A1b' in FIG.

It is expanded at the timing of A1C' and input to the switching circuit 2a. Next, the switching circuit 2a receives the signal (
b), and the 9j conversion circuit 2b outputs a new signal H for after-recording from the AD conversion circuit 1b. Then, the respective signals (b) and high voltage are recorded in the same way as when recording the compression circuits 3a and 3b, the encoding circuits 4a and 4b, the modulation circuits 5a and 5b, the switching circuits 6a and 6b, and the recording amplifier 7a.
, 7b and then recorded again on the magnetic stage 7d sa and 8b at the timing shown in FIG. 3. That is, the third
Rlb in the figure.

The signals recorded as Rlc are R1b', R1o
', recorded on the same track as the original, and R in Figure 3.
In the 2b'2c portion, new signals of R3b and R2O are after-recorded.

Using the above-mentioned after-recording method, if the rotary erasing head is placed in a position that precedes the track scanned by the recording head and follows the track scanned by the preceding playback head, each CH1 and CH2 After-recording of either CH1 or CH2 can be performed using only one rotary erasing head that simultaneously erases CH1 and CH2 without providing a rotating erasing head. Incidentally, the timing of signals erased by the rotary erasing head is also shown in FIG.

Effects of the Invention As explained above, according to the present invention, the time axis is compressed.
Channel audio signals through two rotating magnetic heads! l
In a recording device using 12 tracks, CH1 and CH2 are simultaneously erased using only one rotary erase head, which is installed so as to scan the tracks that precede the rotary recording head and follow the preceding playback head. By doing so, any after-recording of CH1 or CH2 can be performed.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a recording/reproducing circuit for realizing the after-recording method of a recording/reproducing apparatus in an embodiment of the present invention, FIG. 2(a) is a timing chart during recording in the same embodiment, and FIG. (b) is a timing chart during playback of the same embodiment, FIG. 3 is a timing chart during after-recording of the same embodiment, FIG. 4 is a recording format diagram on the magnetic tape in the same embodiment, and FIG. FIG. 3 is a layout diagram of a magnetic head in the same embodiment. 1a, 1b...AD conversion circuit, 2a, 2b...
...Switching circuit, 3a, 3b...Compression circuit, 4
a, 4b...Encoding circuit, 5a, sb...Modulation circuit, 6a. 6b...Switching circuit, 7b...Recording amplifier, 8a, 8b...Rotating magnetic head, 9a, 9
b... Advance reproduction rotary magnetic head, 10a, 10
b...Reproduction amplifier, 11a, 11b...
Demodulation circuit, 12a. 12b...Error correction circuit, 13a, 13b...
...Extension circuit, 14a, 14b...DA conversion circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 4
Figure audio signal H2 3 arrow wound signal

Claims (1)

[Claims] When dividing one field of video signal and recording it on a magnetic tape using two tracks using two rotating magnetic heads of a video tape recorder, a magnetic field that is wrapped more than 180 degrees around a cylinder to which the rotating heads are attached. The tape section has a device for recording time-axis compressed two-channel audio signals on two tracks for each channel using the rotary recording head, and scans tracks located in a position preceding the two rotary recording heads. The rotary erase head mounted on the cylinder scans a track located further ahead of the rotary erase head before simultaneously erasing two tracks of signals on the magnetic tape. Of the two channels of audio signals obtained by the two rotating magnetic reproducing heads attached to the , the channel to be after-recorded is switched to the newly recorded audio signal and supplied to the rotary recording head, and the pre-reproducing rotary head reads the signal. . An after-recording method for a recording/reproducing apparatus, wherein the rotary erasing head rerecords a signal on the erased track.