JPS61238183A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the S/N of the newly recorded signal and to insert and record the clear picture by supplying the memory signal to a sub-recording reproducing head formed wider than the main recording reproducing head, and recording so that the new recording signal can be linked to the old recording signal. CONSTITUTION:When the inserting recording mode is made, a switch Si is changed over, and then a signal Sa supplied through an amplifier 1a to a main recording reproducing head A is supplied to a sub-recording reproducing head A', in the same manner, the signal Sa supplied through an amplifier 1b is supplied to a sub-recording reproducing head B'. For that reason, a recording track An is scanned by the sub-recording reproducing head A', a recording track Bn is scanned by a sub-recording reproducing head B' and then, recording is executed, and in the same way hereinafter, the recording track is successively formed. When such an inserting recording is executed, old recording data are deleted at least two times for the hatching part. Thus, the low area chrominance components which is hard to be deleted are almost deleted and the S/N for the inserting recording part is 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, a recording signal is supplied to the auxiliary recording/reproducing head. With this configuration, the S/N ratio of the inserted recording signal is improved.

[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, a recording current that is 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 (for example, an anime image), the color signal components converted to low frequencies will not be erased sufficiently, resulting in a significant loss of 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 heads is provided, and in the case of insert recording mode, a recording current is applied to the auxiliary recording/reproducing heads. The configuration is such that the tracking servo is applied to the sub-recording/reproducing head at the same time as the sub-recording/reproducing head.

[Effect]

The auxiliary recording/reproducing head has a wider recording track width (for example, 39IL) than the recording track width of the main recording/reproducing head (for example, 27JLm).
m), when a recording signal is supplied to this sub-recording/playback head, the first sub-recording/playback head (A')
The part traced by the second sub-recording/playback head (
Bo) will trace again, and this part will be rewritten twice with new information. Therefore, most of the old information that has already been recorded is erased by at least these two recordings and replaced with new recorded information, which improves the erasing efficiency of chroma components in particular, and provides clear reproduced image quality. .

〔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', and B' are also rad A to the main recording/reproducing at a phase angle of 180 degrees.

The auxiliary recording and reproducing heads A' and B' are set at the same height as B, and the azimuth angle is added to them in the same way, and their width (recording width) is the same as that of the main recording and 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.

Note that FIG. 2 shows the recording track format in the insert recording mode of the magnetic recording/reproducing apparatus of the present invention.
Track An, Bn, An++, Bn++ ”φ・,
indicates the recording track width of the main recording/reproducing head formed in the normal recording/reproducing mode.

In this invention, when recording a new video signal in the insert recording mode from time point To in the Yl area of the magnetic tape that has already been recorded, the video signal to be inserted is inserted into the sub-recording/reproducing head A°.

Switch so that it is supplied to Bo. In other words, ”
As shown in FIG. 3, when entering the insert recording mode, switch S1 is switched from the solid line shown in the figure to the dotted line position, and the signal Sa that was being supplied to the main recording/reproducing head A via the amplifier 1a is transferred to the sub recording/reproducing head. The signal Sa supplied to A' and also supplied via amplifier ib is supplied to sub-recording/reproducing head B'.

Therefore, as shown in FIG.
The sub recording/reproducing head A' scans the recording track Bn.
Recording is performed when the sub recording/reproducing head B° scans the
Thereafter, recording tracks as shown are sequentially formed in the same manner. In this case, as mentioned above, the auxiliary recording and reproducing heads 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 scanned by the sub recording/reproducing head A° and the sub recording/reproducing head B'. This part will be rewritten twice (
(erasing, recording).

Therefore, when such insert recording is performed, the old recorded data will be erased at least twice in the hatch area, so that almost all of the low-frequency color signal components that are difficult to erase as described above will also be erased. Therefore, the S/N of this insert recording portion is improved. Other than the hatched areas, rewriting is performed once as in the conventional insert recording method, and there are some unerased components. , B' is 39pm, then 39-27=12 (ILm), that is, about 40
% will be almost completely erased, so in total, the S/N of the reproduced signal of the rewritten part is 6 dB.
It will be improved to some extent.

Note that 2 indicated by a dashed-dotted line shows the outline of the regeneration circuit; when the switch Sp is connected to the upper side, the mode is normal regeneration mode, and when the switch Sp is connected to the lower side, the mode is the normal regeneration mode. , the reproduction outputs of Rad A' and B' are obtained for sub-recording and reproduction, and in this case, they are used in trick modes such as double speed, slow reproduction, and still reproduction.

Main recording/reproducing heads A, B and sub recording/reproducing heads A', B
' is installed so that the phase angle is approximately 180 degrees, so the tracking servo is used to match the trajectory of the main recording/reproducing head A (B) and the trajectory of the sub recording/reproducing head A'(B'). It is necessary to provide a reference signal delayed by approximately 1 minute.

FIG. 4 shows a servo block diagram when tracking servo is taken by a capstan, and 10 is equipped with main recording/reproducing heads A, B and sub-recording/reproducing heads A', B' as mentioned above. A rotating head, 11 is a CTL head that detects the CTL signal of the tape, 12 is a capstan motor, 12a is an FG (frequency generator) that generates pulses proportional to the rotation speed, 13 is an FC amplifier, and 14 is a rotating head. A speed detection circuit, 15 a speed error output circuit, 16 a CTL signal shaping amplifier, 17 a phase comparator for detecting the difference from the reference signal, 18 a phase error signal amplification/phase compensator, and 19 a phase error signal and phase compensator. 20 is a tracking error signal amplification/phase compensator; 21 is the capstan motor 12;
22 is an internal reference signal source, 23 is a tracking multivibrator that outputs a square wave, and 24 is an insert recording mode and normal recording.

A reproduction mode switching circuit 25 indicates a delay circuit having a delay time of one field, and S+ indicates a switch which is switched as shown in the figure in the insert recording mode.

As is well known, in normal recording mode, this tracking servo circuit compares the phase of a signal obtained by shaping a vertical synchronization signal and a CTL signal detected by a CTL head, and detects the phase error signal component. The speed error signal of the capstan motor 12 is supplied from the mixing circuit 19 to the drive circuit 21 of the capstan motor 12, and phase and speed control is performed, but in the insert recording mode, the switch Si in the switching circuit 24 is reversed. and the reference signal is approximately 1 field (rotation angle 1
Rad A to main recording playback by delaying (by 80 degrees)
, B scans the recording track A',
B' controls the scanning.

Note that the main recording/reproducing heads A and B and the sub recording/reproducing head A'
, B' is at an angle θ other than 180 degrees, if the delay time of the delay circuit 25 is set corresponding to the angle θ, tracking of the recording area in the insert recording mode and the conventional recording area can be matched. Can be done.

[Effect of dawn]

As explained above, the magnetic recording/reproducing device of the present invention has the following features:
In insert recording mode, the recording signal is supplied to the auxiliary recording/reproducing head, which is wider than the main recording/reproducing head, and recording is performed so that the new recording signal is connected to the old recording signal. Approximately 40% of the data is erased twice, which has the effect of improving the S/N of the newly recorded signal and making it possible to insert and record a clear image.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the rotary head employed in the magnetic recording/reproducing device of the present invention, Fig. 2 is a tape recording pattern in erase mode, Fig. 3 is a head switching block diagram, and Fig. 4 is a tracking servo block. It is a diagram. In the figure, A and B are main recording and reproducing heads, A'' and B' are sub recording and reproducing heads, and Sl is a switch.

Claims (1)

[Claims] In a helical scan type magnetic recording and reproducing device that includes a pair of main recording and reproducing heads and a pair of sub recording and reproducing heads that are formed wider than the main recording and reproducing head, in insert recording mode, a recording signal is transferred to the pair of sub recording and reproducing heads. and a device for changing the phase of the reference signal supplied to the tracking servo circuit by a tracking error amount corresponding to the mounting angle of the main recording and reproducing head and the auxiliary recording and reproducing head. Features of magnetic recording and reproducing device.