JPS62183004A - Video tape recorder - Google Patents

Abstract

PURPOSE:To eliminate the delay due to the processing and to attain the preceding extraction of a signal between the processings by providing a digital sound signal reproducing head in preceding over the required time of the recording and reproducing processing. CONSTITUTION:A sound signal is subjected to recording processing 7 including A/D conversion and time axis compression and the result is fed to a head being the 2nd head recording a signal during the period except the video period for the purpose of the recording, and a head 12 is provided to a location preceding from the head being the 2nd head by a sum of times required for the recording processing at the recording and required for the reproducing processings (decoders) 17, 18 including the time axis expansion and the D/A conversion corresponding to the recording processing at the reproduction, and a reproducing signal by the head 12 is subjected to reproducing processing to reproduce the sound signal and a digital signal processing other than the reproducing processing of the reproducing signal at the time corresponding to the time over said sum of times is applied. Thus, the signal is extracted precedingly at the required processing time and the delay due to the processing is eliminated.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a videotape recorder for professionals used in broadcasting stations and the like. [Summary of the Invention] The present invention provides a so-called synchronous l
- When recording a digital audio signal in place of a synchronization signal on a rack, the playback head for this digital audio signal is provided in advance of the time required for processing during recording and playback, and during playback,
This time is shifted so that digital signal processing other than playback processing can be performed during this advance time. [Prior Art] In a video tape recorder of the so-called SMPTF-C format, a 21 tf+l head is provided on a rotating drum, and this drum is rotated by a sub-table that rotates once per field, and each drum rotates once per field. 360 on the circumference
The magnetic tape is wound diagonally over nearly 100 degrees and is transported at a predetermined speed. Then, one of the above-mentioned 2111+1 heads records the image of the video signal, and during the period when this head is separated from the magnetic tape (synchronization period), the signal is recorded by the other head. In other words, Figure 4 shows the recording pattern of the magnetic tape recorded in this way. In the figure, the magnetic tape is divided into two in the width direction, and the above-mentioned pattern is placed on the wide divided part. One head records the video period signal on the diagonal track, and the other head records the synchronization period signal on the diagonal track in the divided narrow part. A control track and first, second, and third audio signal tracks are provided in the middle and on both side edges of the magnetic tape, respectively, which are recorded by fixed heads.By the way, in such a format, the playback signal is By using a so-called time base collector, even if the synchronization period signal is lost, as long as the video period signal is obtained, the regular video signal can be converted to 11'/l without any problem.Therefore, in the above formant, One idea was to record a digitized audio signal on a diagonal track in a narrow section instead of the synchronization period signal.In other words, in the conventional format mentioned above, the audio signal was recorded in analog with a fixed head. However, with this kind of analog recording, the deterioration is significant, especially when dubbing is repeated.On the other hand, if recording is done digitally, the problem of deterioration during dubbing will be solved.However, in that case, when the digital signal is There is no problem when dubbing to a skewer, but if you try to process the digital signal with a transversal filter for editing etc., the signal will be delayed by one to several sampling periods. Since signal processing is performed in units of, for example, one field, if even a small delay like the one described above occurs, there is a risk that recording after construction will not be possible properly. During recording and playback, a time delay occurs in the signal due to AD-DA conversion, error correction, etc. during recording and playback.This delay occurs when processing is performed for one field. 1 field when recording,
During reproduction, the number of fields is more than one field for error correction and the like. Therefore, in the above-mentioned recording device, the recording head and the playback head are made independent, and the playback head is placed in advance by the above-mentioned time delay, so that the timing of the reproduced audio signal coincides with the time of recording. has been done. [Problems to be Solved by the Invention] As mentioned above, in the conventional technology, when attempting to process a digital signal for editing etc., there was a problem in that the signal was delayed and normal recording could not be performed. . [Means for Solving the Problems] The present invention has a rotating drum provided with a first head for recording a video period of a video signal and a second head for recording a period other than the video period. The first head and the second head record on each part of the magnetic tape, which is diagonally transferred along the circumferential surface of the rotating drum, divided into two parts in the width direction. In the video tape recorder that is configured to perform recording processing (encoder (71) L , when recording is performed by supplying a head corresponding to the second head on the rotating drum, the time required for the above recording process during recording and the time corresponding to the above recording process during playback. The third head (12
) ((368) (36B)), performs the reproduction processing on the reproduction signal by the third head to reproduce the audio signal, and reproduces the audio signal at the position provided in advance of the third head. At the time corresponding to the minute greater than the sum of the hours,
Digital signal processing other than the above playback processing of the above playback signal (
This is a video tape recorder capable of performing an editing control circuit (26). [Operation] According to this, it is possible to take out the signal in advance for the time required for processing, so it is possible to solve the problem of delays caused by processing. [Embodiment] In the block diagram of FIG. 1, an analog audio signal supplied to an input terminal (1) is supplied to an AD conversion circuit (3) through a 10 circuit (2) and converted into digital data. This data is supplied to the data bus (4). The data on this data bus (4) is supplied to the memo (January 5) and stored therein. Furthermore, the data stored in the memo 5) is supplied to the encoder (7) through the data processor 6), where it is encoded by adding a predetermined error correction code, rearranging, etc. And the data from the memo January 5) is the modulation circuit (8)
A signal based on the modulated data is supplied to the recording head (JO) through the recording amplifier (9), and the diagonal recording of the narrow portion of the magnetic tape (11) corresponding to the above-mentioned synchronization track is performed. Recorded in Tora Tsuku. The configuration of the rotating drum on which the recording head (10) is provided is shown in FIG. In the figure, the drum is rotated clockwise and twelve heads are provided around its periphery at angular intervals of 30 degrees. Then, the digital audio signals are recorded and played back by two heads. Counterclockwise from the 3 o'clock position in the figure, there is an audio signal recording head (IOA) (10B), a video signal erasing head (31), and a video signal erasing head (31). Signal recording/playback head (
32), dummy head (33), playback head (34A) (34B) for checking recording of audio signals, head for variable speed playback of video signal (35), one playback head for audio signal (to 36), variable speed playback One reproducing head (37^) for the audio signal for time use, and the other corresponding heads (36B) and (37B) are provided. Furthermore, during playback, the tape (11) is moved from the playback head (
12) ((34^) (34B) (
368) (36B) (37A) (37B
) The signal reproduced by ) is supplied to the demodulation circuit (14) through the reproduction amplifier (13), and the recorded digital data is ffililMed. this? l The iJM data is supplied to the data bus (15) (16),
The data on this data bus (15) (16) is supplied to the memory (5) and also to the first and second decoders (17) (1B), respectively. Also, -? of the data detected by the f1m circuit (14)? The address is supplied to the memo January 5) via the address bus (19). The data that has been subjected to predetermined sorting, error correction, and other decoding is supplied from the memo to the data bus (4). The data on this data bus (4) is supplied to the DA converter circuit (20) and converted into an analog audio signal, and this signal is taken out to the output terminal (2]) through the 10 circuit (2). Further, the signal from the digital signal input terminal (22) is supplied to the data bus (4) through the digital 10 circuit (23), and the signal from the data bus (4) is output as a digital signal through the 10 circuit (23). It is taken out to the terminal (24). Furthermore, during editing, data from other video tape recorders etc. is passed through the terminal (25) to the composition control circuit 26).
The data from this circuit (26) is supplied to the data bus (4), and the control signal detected by the circuit (26) is passed through the auxiliary bus (27) to the data bus (4).
). Furthermore, FIG. 3 shows a time chart of recording and reproducing operations of this apparatus. Vertical lines in the figure are field boundaries. In this figure, A is the recording operation, for example, the field

The signal AD-converted during the period [0] is encoded in the first half of the next field (1), compressed in the time axis and read out in the second half of this field [1], and then sent to the recording head (IOA) (IOB). Recorded at. On the other hand, B is a playback operation, and for example, field [-2
] The signal reproduced by the playback head (36Δ) (36B) in the first half of field [-2] is decoded from the second half of this field [-2] to the first half of the next field [-1], and then decoded in the next field [-1].

The time axis is extended to the period [0], and DA
converted and extracted. Therefore, in the device described above, the same field

To extract the signal at [0], the reproducing head (36A) (36B) must be provided three or more fields ahead of the recording head (to 10) (lOB). In the case of the device described above, the mounting position of the playback heads (36A) (36B) on the rotating drum is at the recording head (IO8).
Since it is 120 degrees ahead of (IOB),
The actual lead amount is 3-fields. On the other hand, one field for AD-DA conversion and one field for encoding and recording during recording are almost completely necessary, but fields for playback and decoding (error correction) during playback are almost completely necessary. Approximately one field is actually needed, and the remaining approximately one field is redundant. Therefore, in the above time chart, the end of decoding r
After approximately -7 yield until the start of DA conversion, the data is only held in the memo (January 5) and is in a stopped state. Therefore, when data is processed by the above-mentioned editing or the like, the time delay caused by the processing can be eliminated by speeding up the reading of the data from the memo 5) by the time required for the processing. That is, in the above block diagram, the reading of the memo is controlled by the control signal from the editing circuit (26), and reading starts from the beginning of the next field during current playback, and starts reading from the beginning of the next field during editing. Start reading from an earlier point in time. In this way, according to the above-mentioned apparatus, data can be read out early during editing, etc., and thereby processing of data that has a time delay can be performed while eliminating the time delay. Note that the reading of the memo (January 5) can be delayed until the end point r of the field (1) is just before the next field is played. As a result, 1+iS can be achieved even when the video signal is processed to cause a delay in the video signal. Furthermore, the arrangement of the heads on the rotating drum is not limited to the above example. [Effects of the Invention] According to the present invention, it is possible to take out signals in advance for the time required for processing, so that the problem of delays caused by processing can be solved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of the present invention, FIGS. 2 and 3 are diagrams for explaining the same, and FIG. 4 is a diagram for explaining a conventional technique. (1) is the input terminal, (2) is the RO open circuit, (3) is the AD transition circuit f41 (61 (15), (16) is the data bus, (5) is the memory, (7) is the encoder, (8 ) is a modulation circuit, (9) is a recording amplifier, (10) is a recording head,
(11) is a magnetic tape, (12) is a playback head, (13)
) is the reproduction amplifier, (14) is the demodulation circuit, (17) (
1B) is a decoder, (19) is an address bus, (20)
is a DA conversion circuit, (21) is an output terminal, (22) is a digital input terminal, (23) is a digital 10 circuit, (24)
is a digital output terminal, (25) is a terminal, (26) is an editing control circuit, and (27) is an auxiliary lotus. , ′・

Claims (1)

[Scope of Claims] A rotating drum provided with a first head for recording a video period of a video signal and a second head for recording a period other than the video period; on the magnetic tape that is being transferred diagonally.
In a video tape recorder in which recording is performed by the first head and recording by the second head in each divided portion, an audio signal is sent to the head corresponding to the second head.
When recording is performed by supplying a recording process including conversion and time axis compression, a head corresponding to the second head on the rotating drum calculates the time required for the recording process during recording and the time required for playback. A third head is provided at a position that is at least the sum of the time required for playback processing including time axis expansion and DA conversion corresponding to the above-mentioned recording processing of time, and the playback signal by this third head is played back as described above. processing and reproducing the audio signal, and digital signal processing other than the reproduction processing of the reproduction signal at a time corresponding to a time equal to or longer than the sum of the times of the positions provided in advance of the third head. A videotape recorder that made it possible to do this.