JPH0472979A - Video tape recorder - Google Patents

Abstract

PURPOSE:To decrease a deviation of a reproduction signal and to eliminate the need for the adjustment of inserting position of a pseudo vertical synchronizing signal by employing a delay line in the case of using a head of a different mode so as to correct the head arrangement. CONSTITUTION:Outputs of heads A, B, A', B' are fed to a video signal processing circuit 1 based on RF-SW pulse and SUB-H pulse. A video signal after processing is fed to broad band 1H delay devices 2, 3. Then the video signal after processing receives three kinds of delays by the delay lines 2, 3. The selection of a delay time is controlled by controlling switches S4,S5 with delay control signals a, b. In the case of SP mode 1/3 consecutive slow, a delay time of 1H to an A(B) head (1st time), a 2H delay time is given to an A'(B') head and a zero (non delay) is given to the A(B) head (2nd time).

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a video tape recorder capable of special playback.

(b) Conventional technology, for example, Utility Model Application Publication No. 57-69357 (HO4N5/93)
This is a video tape recorder that performs azimuth recording, and in a configuration in which a head is added for special playback, an IH delay line for dropout processing is used to eliminate the influence of -\rad deviation. It is shown.

(c) Problems to be solved by the invention By the way, 1/n slow playback is performed by running the tape continuously at a tape speed slower than the tape speed during recording and scanning the same track multiple times. is possible. In this case, since a special playback head is used and the tape is running continuously, I
H (H is the horizontal synchronization period of the television signal) delay line alone cannot perform the correction satisfactorily.

(d) Means for Solving the Problems Therefore, in the present invention, correction is performed using two IH delay lines used in a logical comb filter for YC separation. Then, the delay time for correction is selected depending on the head used in the reproduction mode.

(E) Effect Therefore, since the reproduced signal is corrected using a combination of a plurality of delay times including zero delay time, the correction can be made satisfactory.

(f) Examples Examples will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment, FIG. 2 is an explanatory diagram of the head arrangement,
FIG. 3 is a block diagram showing the configuration of a 3-line logical comb filter, and FIGS. 4 and 5 are explanatory diagrams regarding 1/3 continuous throw.

In the embodiment, as shown in FIG. 2, heads A (plus azimuth) and B (minus azimuth) for SP (standard) mode, and heads A' (plus azimuth) and B' ( (minus azimuth) is provided. The A head and the B head are arranged 180 degrees opposite each other, and the A
'Head, B.

The heads are arranged 180° opposite each other. And A'
The head is 2H away from the B head, and the A head is 2H apart.
B head is 2H away. The height of the mounting surface is not the same, but there is a 9 μm difference in height.

Next, 1/3 continuous slow playback in SP mode will be explained with reference to FIG. The tape T is progressing to the left in the figure, and the track T1 on the tape is traced three times as A and A'A to obtain an output. As mentioned above, the A head and B head are for the SP mode and have a width of 58 μm. A'
, B° heads are for EP mode and have a width of 32 μm. Then, when considering only the running of the tape and the height difference between the heads (not considering the 2H in the circumferential direction, but assuming that they are 180 degrees opposite each other), for the A head (-th time),
'The head is 0.75H, and the A head (second time) is shifted by IH in the tracing direction and traces the track T1. The same applies to the B and B'B heads for track T2.

Actually, since there is 2H in the trace direction, the signal deviation is as shown in FIG. FIG. 4 shows waveforms for explaining the state and operation of tracing a track using the track pattern coordinate method.

Taking into account the head deviation 2H of the tracing method, the deviation of the reproduced signal is (0,75-2
) H (for A' head), IH (for A head (for the second time)). Therefore, this deviation is calculated by two I
Correct using H delay line.

The configuration will be explained based on FIG. 1 is a video processing circuit, 2.3 is an IH delay line by CCD, 4 is a pseudo ■ signal insertion circuit, 5 is an output terminal, and 6 is a head control signal (RF-8
7 is a servo circuit 8 is a delay control signal generating circuit, and 9 is a pseudo V generating circuit.

The outputs of the heads A, B, A', and Bo are supplied to the video signal processing circuit 1 in accordance with the RF-SW pulse and the 5UB-H pulse (FIGS. 4(A) and 4(B)). The processed video signal is fed to a broadband IH delay line 2.3 (subordinate to 2). Then, the processed video signal is transferred to the delay line 2.3.
Three types of delays (zero, IH12H) are given by . The delay time can be selected using delay control signals a and b.
It is controlled by controlling the switches S4 and S5 according to (FIG. 4 (d) and (e)). In the case of SP mode 1/3 continuous throw, as shown in Figure 4, the IH delay time for the A(B) head (first time) is changed to A'(B).
') head is given a delay time of 2H, and the A(B) head (second time) is given a delay time of zero (no delay).

As a result, the signal deviation is about 0.25H for the output of the A'(B') head, and can be almost ignored. Therefore, the insertion phase of the pseudo-■ signal may always be constant, and no adjustment is required.

As shown in Fig. 3, the two lH delay lines are 3
A line logical comb filter can be used. In this case, during special reproduction, the switch 26 is turned off so that the output of the correlator 20 is not supplied to the subtracter 21. Then, the amount of delay to be applied may be controlled by the changeover switches 22 of the three circuits.

In the above example, the case is 1/3 continuous throw, but
When playing by switching heads during intermittent slow playback, still playback, or high-speed playback, in order to compensate for the 2H deviation, a 2H delay is applied when the leading head is used, and a 2H delay is applied to the trailing head. It is also possible to pass through the process.

(G) Effects of the Invention As described above, according to the present invention, when heads of different modes are used, the head arrangement is corrected using a delay line, so the deviation of the reproduced signal is reduced. There is no need to adjust the insertion position of the pseudo ■ signal, which is effective.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the embodiment, Fig. 2 is an explanatory diagram of head arrangement, Fig. 3 is a block diagram showing another embodiment, Fig. 4,
FIG. 5 is an explanatory diagram of 1/3 throw. ASB, A', B'...Head, 2.3...Delay line, Sl, S5...Switch, 8...Delay control signal creation.

Claims (1)

[Claims] (1) Delay means for giving multiple delay times to the playback output;
A video tape recorder comprising a control means for controlling the delay time according to the head arrangement and the relationship with the track.