JPS62150508A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the efficient recording even with different tape running speeds by providing a dummy data period increasing/decreasing in the lengthwise direction of a recording track depending on the tape running speed at recording between a digitized video signal and a digitized sound signal to as to prevent quality deterioration after recording. CONSTITUTION:A speed changeover switch 72 is switched to the position of speed control terminals 65, 66 of a motor drive circuit 67 depending on the tape running speed to control the number of revolutions of a capstan motor thereby controlling the tape running speed. The switching signal is fed to a timing control circuit of a data split/incorporating circuit through a line 59. Thus, the number of revolutions of the capstan motor is controlled and its information is fed to the data split/incorporation circuit, where the dummy data period is increased/decreased in response to the tape running speed. Thus, the dummy data period corresponding to the tape running speed is inserted between the video and sound recording tracks and the after recording with high recording efficiency and high quality realized.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a magnetic recording and reproducing device suitable for after-recording (hereinafter referred to as dubbing) in which audio etc. are later re-recorded in a digital magnetic recording and reproducing device. Regarding.

[Background of the invention]

2. Description of the Related Art Digital VTRs and the like are devices that digitize video and audio signals and magnetically record and reproduce them on magnetic tape. With this device, dubbing is possible by recording digital (image signals and digitized audio signals in separate areas (called recording tracks). Japanese Patent Publication No. 59-151309
A method is described in which a magnetic gap for oil extraction is provided only at the position corresponding to the track where the information to be erased is recorded. There is no mention of how to connect. Therefore, in the following cases, the quality at the time of dubbing was lowered. If the gap between the video and audio tracks is composed of continuous valid data, the following inconvenience will occur. Figure 2,
FIG. 3 is a diagram showing the relationship between the recording track, the recording track, and the post-recording sound section erasing head 1 in this case. Here, 1 is an erasing head, 2 is an audio erasing gap part, 3 is a magnetic tape, and 7
1 is a control track, 10 is a video recording tractor, and 11 is an audio recording tractor. Assuming that the recording tracks are formed as shown in FIGS. 2 and 3, when performing audio dubbing, the recording tracks are formed as shown in FIGS. 2 and 3.
- Since the angles formed by the sound erasing gap 2 are not parallel, depending on the setting position of the erasing head, the necessary data area 13 may be erased, or an unerased area 12 may be left. This resulted in missing data, overlapping portions, increased data errors, and a significant deterioration in quality.

In addition, in order to prevent this increase in errors, the 8 m VTR tape format (Nikkei Electronics 1983
May 23, 2015, issue P144 etc.) stipulates the dubbing margin for a certain period of time. However, in recent years there has been a growing need for longer recording times, and this has led to a need for lower tape running speeds and more efficient recording. For this reason, there is no regulation regarding the increase or decrease in the margin period due to possible changes in the tape running speed tt. For this reason,
By keeping the margin period constant in this manner, it is not possible to cope with a decrease in the required period of the margin as the length of time increases, and there is a drawback that efficiency decreases due to setting invalid recording portions on necessary sides.

[Purpose of the invention]

It is an object of the present invention to provide a magnetic recording/reproducing apparatus which is capable of post-recording in response to changes in tape running speed due to longer recording times.

[Summary of the invention]

- The present invention provides an angle between the recording track and the longitudinal direction of the tape (hereinafter referred to as tape recording angle) depending on the tape running speed.
By paying attention to the fact that the post-recording margin changes with the change in the post-recording margin and increasing or decreasing the post-recording margin period, high-quality post-recording with high recording efficiency is made possible.

Next, the concept will be explained with reference to FIG. Here 4 and 4
′ indicates a dummy data period for post-recording margin. This dummy data period length T is the recording track width Tn'n
When 'L, it is expressed by the following equation.

T > Trw / -〇 - Song interval (1) Also, the tape recording angle θ can be calculated using the following formula.

θ=ratio (P0 possible)... (2) However, P
The foot frequency, Vt, indicates the tape running speed.

According to these formulas, the dummy data period length required to perform dubbing without any inconvenience needs to be greater than the dummy data morning length TAI determined by the tape running speed Vt.

When recording and reproducing over a long period of time, it is necessary to increase the recording density and slow down the tape running speed. Additionally, the tape recording angle changes as a result of this change. This situation is shown in Figure 1.6 As shown in Figure 1 (a), when the tape running speed is slower than in (b), the tape recording angle θ becomes narrower, so the dummy is The data period T can be shortened. Furthermore, it is possible to increase the recording area accordingly, and it is possible to perform highly efficient and high-quality dubbing over longer periods of time.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram showing the circuit configuration of one embodiment. The video signal 31 is input to the A/D, digitized, and then input to the data division circuit. Furthermore, the audio signal 23 is digitized by A/D, and the data division circuit 2
Enter 7. Here, by using memory, the digitized video signal and the digitized audio signal are compressed into only valid data excluding the video blanking period. Dummy data for a fixed period is inserted after the compressed digitized audio data and the video data in a period left vacant due to compression. This dummy data period length is varied depending on the tape running speed. Thereafter, the time-divided digitized video and audio data are added with parity for error correction by an encoder 25, converted into a form suitable for magnetic recording by a parallel/serial conversion circuit 24, and then sent to a recording amplifier 23. The signal is amplified and recorded on the tape 3 by the head 22 in the format shown in FIG. The digital signal reproduced by the heave 22 is amplified by a reproduction 7' amplifier 32, and converted into a form suitable for digital processing by a serial/parallel conversion circuit 33. Next, the decoder 34 performs error correction based on parity, and then the data integration circuit 3
At step 6, the dummy data period is removed, the data is separated into digitized video data 37 and audio data 39, and expanded to the original signal. Thereafter, it is converted back into an analog video signal 38 and an audio signal 40 by a D/A converter. Here data division 27
The detailed circuit configuration of the integrated circuit 36 will be explained with reference to FIGS. 5 and 6. FIG. 5 shows an embodiment of the data division circuit. As shown in the upper part of FIG. 8(a) of the digitized video signal 30, only the valid portion 47 of the video data is recorded in the memory 52 as a digitized video signal. At the time of reading, if the data is read in the order in which it was written, data 50 compressed into only valid data, excluding the blanking periods 48 and 49, can be obtained as shown in the lower part of FIG. 8(a). Here, 51 is a data space obtained by compressing video data.

After the digitized audio signal 28 is latched 51, it is written into the memory 53, and by reading out the signal faster than writing, the digital data can be compressed as shown in FIG. 8 (co). Next, the compressed digitized image data is selected by the selector 54, and the dummy data generation circuit 55
Select the dummy data generated in the above-mentioned period. The period length T of this dummy data is determined by a tape running speed determining circuit 56 based on a capstan servo signal 59, and is increased or decreased in accordance with the determined speed data 57. Now, by selecting the compressed digitized audio data, dummy data 53 corresponding to the traveling speed of the slave is inserted between the video data 51 and the audio data 52 as shown in FIG. 8(c), and the data is divided. By processing the processed data 26 as shown in FIG. 4, recording suitable for dubbing can be performed. FIG. 6 shows an embodiment of the data integration circuit, in which reproduced digital data 35 and speed data 58 . Memory 52.
53 and its timing control circuit 60, the digitized video signal 3 is
7 and a digitized audio signal 39.

Figure 7 shows the capstan servo system. 60 is a rotating cylinder, 69 is a cylinder motor, 63 is a capstan, 7
0 is a capstan motor. By switching the speed/night selector switch 72 to the speed control terminals 65 and 66 of the motor drive circuit 67 depending on the tape running speed, the rotation speed of the capstan motor is controlled and the tape running speed is controlled. This switching signal 1 is sent through 59 to the timing control circuit of the data division/integration circuit. By controlling the rotational speed of the capstan motor in this way and sending the information to the data division/integration circuit, the dummy data period is increased or decreased in accordance with the tape running speed IW. According to the first embodiment, a dummy data period corresponding to the tape running speed can be inserted between the video and audio recording tracks, resulting in high recording efficiency.
High-quality dubbing can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, one video recording track and one audio track
．． By providing a dummy data period between recordings, quality deterioration during post-recording can be prevented, and efficient recording can be performed in response to different tape running speeds.

Note that the present invention can also be applied to a case where the audio data does not exist at the recording position of the audio data, but is located near the center of the recording track, for example. The dummy data can also include synchronization signals and field information other than video and audio data.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing changes in the post-recording margin due to differences in tape running speed. Figures 2 and 3 are schematic diagrams showing inconveniences that occur when the post-recording margin is not set. A block diagram showing an embodiment for realizing the invention, FIG. 5 is a configuration program of a data division circuit,
Figure 6 is a configuration diagram of the data integration circuit, Figure 7 is a schematic diagram showing the tape regularization system, and Figure 8 is a conceptual diagram showing data compression and time division. . 2... Demagnetization gap, 3... a staple, 4.
4'...Margin for dubbing, 10...Video recording track, Vri, 11...Audio recording track, 23...Recording amplifier. The 1st country also closed 3rd and 7th ir. horse 5m

Claims (1)

[Claims] The video signal and audio signal are digitized, the digitized audio signal is compressed on the time axis, and a certain digitized audio signal is inserted into the certain digitized video signal in a time-sharing manner. A magnetic recording and reproducing device for recording and reproducing information on a track, characterized in that a dummy data period that increases or decreases in the longitudinal direction of the recording track depending on the tape running speed during recording is provided between a digitized video signal and a digitized audio signal. Recording and playback device.