JPH0210573Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a playback device for playing back magnetic tapes, magnetic sheets, etc., and particularly relates to a pause device in the playback device.

Background technology and its problems Helical scan type using a rotating head
On a VTR, when you press the pause button during recording or playback, the tape stops and the head continues rotating. Therefore, the head may repeatedly trace the same location on the tape, damaging the tape. If the tape is paused during playback, damage to the tape will result in a dropout of the signal recorded on the track. In the case of high-end machines, when the tape is set to pause, the tape loosens and moves away from the drum, but in the case of ordinary home VTRs, the head rotates while in contact with the tape in the pause state, causing the above-mentioned problem. .

Purpose of the invention The object of the invention is to solve the above-mentioned problems in a reproducing apparatus that performs reproduction while intermittently feeding a recording medium or a head.

Summary of the invention The present invention provides a reproducing apparatus which performs reproduction while intermittently running the recording medium in the longitudinal direction, in which recording tracks are formed that are inclined with respect to the longitudinal direction of the recording medium. This is a playback device in which a playback head traces across two adjacent tracks.

Embodiment This embodiment is a case in which the present invention is applied to a VTR which performs playback while feeding the tape intermittently. In a VTR that advances the tape intermittently, the tape is run intermittently on a track pitch, and when the tape stops for a predetermined period of time, the rotating head traces a video track formed diagonally on the tape and plays it back. ing. Therefore, the slope of the trajectory of the rotary head on the tape in the paused state corresponds to the slope of the video track.

FIG. 1 shows a case where a tape 1 recorded with a guard band is played back.

On the tape 1, tracks 2 _A1 , 2 _A2 , etc. recorded on the A head of the two rotating heads, and tracks 2 _B1 , 2 _B2, ... recorded on the B head, with a guard band ₃₁ between them. , 3 ₂ , 3 ₃ . . . are formed alternately. When playing, point tape 1 with arrow a
While the tape 1 is stopped for about one field period while being intermittently fed in the direction, the A and B heads trace the corresponding tracks and playback is performed.

When the pause button is pressed in this playback state, the tape 1 is stopped and the A and B heads each trace the same location on the tape 1. A at this time,
The slope of the trajectory of the B head matches the slope of the track. In this state, finely adjust the positions of the A and B heads to align the guard bands 3 ₂ and 3 3 with the guard bands 3 ₂ and 3 ₃ so that they follow the trajectories 4 _A and 4 _B indicated by diagonal lines in Fig. ₁ . Adjacent tracks 2 _B1 and 2 _A
2 , 2 _A2 , and 2 _B2 are traced. In this case, each track 2 _B1 , 2 _A
Traced parts 4a, 4b of ₂ , 2 _A2 , 2 _B2 ,
4c and 4d have approximately the same area. Furthermore, A,
For the fine adjustment of the B head, a known dynamic trace device using a piezoelectric element may also be used. The dynamic trace consists of A and B heads attached to piezoelectric elements, and this piezoelectric element attached to a rotating drum.A control voltage is supplied to the piezoelectric elements so that the playback output level of the heads is maximized during playback. In this method, automatic tracking is performed by finely adjusting the head position. Therefore, A,
In order to trace the B head with the trajectories _4A and _4B, the above parts 4a, 4b, 4 in the pause state
A control voltage may be applied to the piezoelectric element so that the reproduced output level of signals c and 4d becomes lower by a predetermined ratio with respect to the maximum reproduced output level during reproduction.

FIG. 2 shows a case in which each track is formed by so-called solid recording by changing the azimuth of the head between adjacent tracks without providing a guard band, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In this case, the adjacent track 2 in the pause state
The trajectories of the A and B heads are adjusted so that approximately half of each of _A1 , _2B1 , 2B1, and _2A2 is traced.
In this case, by shifting the trace points, the area of the track to be traced becomes smaller, and the area of tracing adjacent tracks increases. However, since the azimuths are different, it is not possible to obtain a large reproduction output from adjacent tracks. Therefore, in this case as well, if a control voltage is applied to the piezoelectric element so that the playback output level is a predetermined level lower than the maximum playback output level during normal playback, the playback head can straddle two adjacent tracks. The trace trajectory can be adjusted accordingly.

According to the above, in the pause state, each part of the two adjacent tracks 4a, 4b, 4
Since only the signals c and 4d are traced by the rotary head along the trajectories _4A and _4B , the missing portion of the signal is small and the influence can be substantially eliminated.

FIG. 3 shows an embodiment of a tracking device for adjusting head position.

In the figure, a piezoelectric element 10 has a drive electrode 1
1 and a common electrode 13 are provided. tape 1
One of the video heads 14, one of the A and B heads for reproducing 2 images, is attached to the piezoelectric element 10. The circuit shown in FIG. 3 is for adjusting the position of one of the A and B heads, and a similar circuit (not shown) is also provided for the other head. The reproduced signal from the head 14 is applied to a detection circuit 16 through an amplifier 15 and subjected to envelope detection. The level of this detection output is held by a hold circuit 17. The rotating drum (not shown) to which the A and B heads are attached is equipped with a pulse generator that detects the rotation of the rotating drum, and this pulse generator generates one PG pulse per rotation of the rotating drum. can get. This PG pulse is terminal 1
8 to the timing circuit 19. Timing circuit 19 supplies a hold signal to hold circuit 17 at a predetermined timing. Based on this, the hold circuit 7 holds the detection output of the detection circuit 16.

During normal reproduction, the comparator circuit 20 compares the current held voltage obtained from the hold circuit 17 with the held voltage held at the previous timing. This comparison output is applied to a drive circuit 22 after noise is removed through a low-pass filter 21.
The drive circuit 22 applies a drive voltage corresponding to the comparison output to the drive electrode 11 of the piezoelectric element 10. As a result, the amount of deflection of the piezoelectric element 10 is controlled so that the reproduction output level of the head 14 is always at the maximum level.

In this playback state, when the pause button is pressed to enter the pause state, a pause signal is sent to the terminal 23.
PA is added. As a result, the comparison circuit 20
A comparison output is given to the drive circuit 22 so that the reproduced output level of the head 14 is attenuated, for example, by about 6 dB from the maximum level. This allows head 14 and the other heads to
Tracing will be performed along trajectories 4 _A and 4 _B in the figure.

Effects of the invention It is possible to effectively prevent damage to the tape and signal dropout in the pause state of conventional VTRs.

[Brief explanation of the drawing]

1 and 2 are front views of a tape showing an embodiment of the present invention, and FIG. 3 is a block diagram showing an embodiment of a head tracking device. In addition, in the symbols used in the drawings, 1...
...Magnetic tape, 2 _A1 , 2 _A2 ... Track, 2 _B1 ,
2 _B2 ...Track, 4a to 4d...Trace portion.

Claims (1)

[Claims for Utility Model Registration] A reproducing device configured to perform reproduction while intermittently running the recording medium in the longitudinal direction, the recording medium having a recording track inclined with respect to the longitudinal direction of the recording medium, A detection circuit that envelope-detects the playback output of the playback head, a hold circuit that holds the envelope detection signal output from the detection circuit at a predetermined timing, and a holding voltage of the previous timing held in the hold circuit and the current state. a comparison circuit for comparing the reproduction output voltage of the recording medium; and a drive voltage corresponding to the comparison output of the comparison circuit is applied to the piezoelectric element to which the reproduction head is attached to control the trajectory of the reproduction head tracing the recording medium. a drive circuit, and when a pause signal is given to the comparison circuit, tracking is performed such that the playback output of the playback head is attenuated by a predetermined amount from the maximum level of the playback output during normal playback. A reproducing apparatus characterized in that a comparison output to be performed is derived to the drive circuit, and in a pause state, the reproducing head traces across two adjacent recording tracks.