JPS61238187A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record a new recording signal continuously after an old one and to insert and record a clear picture by supplying an erasing signal to a sub- recording and reproducing head formed in a wider shape than a main recording and reproducing head when the operation is in an insert recording mode and then rewriting the signal in the main recording and reproducing head. CONSTITUTION:The main recording and reproducing heads A and B are provided at a phase angle of 180 deg., and their azimuth angles are different. The sub-recording and reproducing heads A' and B' are set at the same height of the main recording and reproducing heads A and B with the same phase angle of 180 deg., given by the azimuth angle, and their widths (recording width) are set wider than the main recording and reproducing heads A and B. The advancing sub-recording and reproducing head B' erases (rewrites) a recording track An with the aid of a luminance signal, and then the following main recording and reproducing head A records the signal on the recording track An. When such insert recording is executed, a hard-to-erase low pass chrominance signal can be almost erased, and an S/N in the insert recorded part can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus that does not have a flying erase head and is adapted to perform insert recording.

[Summary of the invention]

The present invention provides a helical scan type magnetic recording/reproducing device equipped with a main recording/reproducing head and a wide auxiliary recording/reproducing head used for variable speed reproduction, etc. In an insert recording mode, an erase signal is supplied to the auxiliary recording/reproducing head. In addition, the S/N ratio of the inserted recording signal is improved by supplying the recording signal to the main recording/reproducing head.

[Conventional technology]

A typical rotating two-head helical force scan type magnetic recording/reproducing device is configured so that in the recording mode, a fixed erasing head erases the entire width of the magnetic tape, and then a rotating head records a new signal. ing. Therefore, for example, when inserting a new video signal into a tape on which an old video signal is recorded,
Since the old recorded signals formed in the diagonal direction are erased in the direction perpendicular to the tape, the joint area becomes discontinuous and the image becomes distorted during playback.

High-end magnetic recording and reproducing devices, such as those used in broadcasting stations, are equipped with a flying erase head on the rotating drum side, allowing for insert recording in which data is erased diagonally along the recording track, and then a new video signal is recorded. However, it is necessary to provide an expensive flying head, resulting in high costs. Therefore, insert recording is performed in which a recording current several tens of percent higher than the normal recording current is supplied to the normally used rotary recording/reproducing head to rewrite the old video signal with a new video signal.

[Problem that the invention seeks to solve]

By the way, the signal components recorded on magnetic tape generally have the property that high frequency components are recorded in layers close to the surface of the magnetic tape, and low frequency components are recorded deep into the magnetic tape, so the above-mentioned rewriting method is not suitable. If the old image has a high color level, such as an anime image, the color signal components converted to low frequencies will not be erased sufficiently, resulting in a significant loss in the quality of the newly written image. be.

The present invention was made in order to alleviate such problems, and provides a magnetic recording/reproducing apparatus that allows the reproduced image quality of insert recording to become clearer.

[Means for solving problems]

For a pair of main recording/reproducing heads, a pair of auxiliary recording/reproducing heads whose recording track width is set larger than that of the main recording/reproducing head is provided, and in the case of insert recording mode, erasing is performed in the preceding auxiliary recording/reproducing head. At the same time as passing current,
It is configured to send a signal to be recorded to the subsequent main recording/reproducing head.

[Effect]

The auxiliary recording/reproducing head has a wider recording track width (for example, 39JJ) than the recording track width of the main recording/reproducing head (for example, 271Lm).
, m) and are arranged at approximately the same position. Therefore, when an erase signal is supplied to this sub-recording/playback head, the trace traced by the first sub-recording/playback head (A') is traced by the second main recording/playback head. The reproducing head (B) will scan, and in the next track, the first main recording/reproducing head (A) will trace what has been traced by the second sub-recording/reproducing head (B') to which the erase signal is supplied. It will be scanned. Therefore, in the insert recording area, the recording tracks are erased at least twice, and in particular, some of the recording tracks are erased three times.
It is repeatedly erased and rewritten with new information. Therefore, most of the old information that has already been recorded is erased through at least two erasing actions and then replaced with a new recorded signal, which improves the erasing efficiency of chroma components in particular and provides clear reproduced image quality. become.

〔Example〕

FIG. 1 is a plan view showing an example of a rotary head applied to the magnetic recording/reproducing apparatus of the present invention, and A and B are two main recording/reproducing heads with different azimuth angles, which are provided at a phase angle of 180 degrees. , A', B' to the main recording/reproducing mode with the same phase angle of <180 degrees.

The sub recording/reproducing heads A' and B' are set at the same height as B, and the azimuth angle is added to the sub recording/reproducing heads A' and B' in the same way, and their width (recording width) is the same as that of the main recording/reproducing heads A, B'.
It is set larger than the width of B. The sub-recording and reproducing modes A' and B' are normally used when performing trick playback such as double speed playback, slow playback, still playback, etc. with a clean picture.

FIG. 2 shows the recording track format in the insert recording mode of the magnetic recording/reproducing apparatus of the present invention.
Track A n, B n, A n41. B ni
l 11 . . . indicates the recording track width of the main recording/reproducing head formed in the normal recording/reproducing mode.

In this invention, the Yl of the magnetic tape that has already been recorded is
When recording a new video signal in the insert recording mode from time point To in the area of switch so that it is supplied with That is, as shown in FIG. 3, when the switch S1 is turned on to enter the insert recording mode, the signal Sa that was being supplied to the main recording/reproducing head A via the amplifier 1a is transferred to the preceding sub-recording/reproducing head B°. Also supplied to
Similarly, the signal Sb, which has been supplied to the main recording/reproducing head B via the amplifier 1b, is also supplied to the auxiliary recording/reproducing head A'.

2a (2b) and 3a (3b) respectively indicate buffer amplifiers, and the buffer amplifier 3a (3b) includes a trap circuit 4 for removing chroma components from the video signal.
a (4b) provided. Therefore, only the FM-modulated luminance signal is supplied to the sub recording and reproducing heads A' and B'. As a result, as shown in FIG. 2, the recording track An is first erased (rewritten) by the luminance signal by the preceding sub recording/reproducing head B°, and then the signal is recorded by the primary recording/reproducing head A that follows. Truck An
recorded in Similarly, in the next recording track Bn, the preceding sub recording/reproducing head A' first performs an erasing operation, and the main recording/reproducing head B records a signal. In this case, as mentioned above, RAD A',
Since the width of B' is wider than the track width of the main recording/reproducing heads A and B, the area indicated by the hatched line is the area where the auxiliary recording/reproducing head A' and the auxiliary recording/reproducing head B' scan. It will be rewritten by main recording/reproducing head A or B, and this portion will be rewritten (erased and recorded) three times.

Therefore, when such insert recording is performed, the old recorded data will be erased at least three times in the hatch section EE, and the third time the main recording/playback head A will be erased.
, B. Therefore, as described above, most of the low-frequency color signal components that are difficult to erase are also erased, and the S/N of this insert-recorded portion is improved. In addition, except for the hatch part, the insert recording is the same as when using a flying erase head, and there is a concern that there may be a slight amount of unerased material due to the difference in head function. If the track width of the reproducing heads A' and B' is 397 zm, then 39-27=12 (pm), or approximately 40%, will be almost completely erased. Compared to the case of rewriting with B, the S/N of the reproduced signal of the rewritten portion is significantly improved.

5 indicated by a dashed line in Fig. 3 shows an outline of the regeneration circuit. When the switch SP is connected to the upper side, the normal regeneration mode is entered, and the switch Sp is connected to the lower side. In this case, the reproduction output of the sub-recording and reproduction heads A' and B' is obtained, and in this case, it is used in trick modes such as double speed, slow reproduction, and still reproduction.

Since a signal obtained by removing the chroma component from the recording signal is used as the erasing signal, it has the characteristic that effective insert recording can be performed by adding a few circuits and switches to the conventional recording circuit. Note that the erase signal may be supplied from a separate oscillator.

〔Effect of the invention〕

As explained above, the magnetic recording/reproducing device of the present invention has the following features:
In insert recording mode, an erase signal is supplied to the sub-recording/playback head, which is wider than the main recording/playback head, and then the main recording/playback head performs rewriting, so the old recording signal is replaced with the new recording. In addition to being able to record so that the signals are connected, at least 40% of the old recorded signal area is erased three times, improving the S/N of the newly recorded signal and inserting and recording a clear image. It has the effect of being able to

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a rotary head employed in the magnetic recording/reproducing apparatus of the present invention, FIG. 2 is a tape recording pattern in erasing mode, and FIG. 3 is a head switching block diagram. In the figure, A and B are main recording/reproducing heads, A'' and B'' are sub recording/reproducing heads, and Sl is a switch.

Claims (1)

[Claims] In a helical scan type magnetic recording/reproducing device comprising a pair of main recording/reproducing heads and a pair of auxiliary recording/reproducing heads formed wider than the main recording/reproducing heads, in the insert recording mode, the above-mentioned recording/reproducing head that precedes the erase signal is used. 1. A magnetic recording and reproducing apparatus characterized in that a device is added for supplying a recording signal to a pair of sub recording and reproducing heads and also supplying a recording signal to the main recording and reproducing head.