JPS6284479A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To write data at a prescribed position by rewinding a tape by a fixed amount while control pulses are counted at a reproduction/pause position, applying a reproduction tracking servo to send the tape in a normal direction and recording index information when the difference between counted values reaches a prescribed value. CONSTITUTION:When the titled device is made in a reproduction/pause state and an index key is pressed, normal/reverse signals and on/off signals are inputted to a capstan motor control circuit 5. Then a capstan motor reversely rotates for the prescribed time, and the tape 3 travels in a winding direction. Simultaneously a control circuit 1 counts reproduction control pulses (PBCTL) outputted from an amplifier 6. When the index key is again depressed, the motor 4 starts rotating in the normal direction, and the control circuit 1 counts down the PBCTL. When the difference between them reaches the prescribe value, an index information write command is outputted from the control circuit 1, amplified by an amplifier 7, and transmitted to a control head 2 through a switch 8, thereby recording the index information on the tape 3.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a magnetic recording/reproducing device such as a video tape recorder, and particularly to one in which the duty of a control signal is changed to be used as index information.

<Prior Art> It is well known that index information used for various controls such as cueing and tape end detection is recorded separately from main signals such as audio signals and video signals recorded on a magnetic tape. For example, there is a method in which the duty of the control signal recorded on the control track at the side edge of the tape is changed in order to control the recording/playback operation of the main signal, and this is used as index information. JP-A-57-15238, JP-A-57-
It is described in Publication No. 46584 and the like.

<Problems to be Solved by the Invention> Conventional devices that change the duty of the track signal to obtain index information record index information during playback. The configuration is such that index information can be recorded by operating the index button while using the camera. For this reason, the position where the index information is recorded often deviates from the position where it is actually desired to be recorded, making it difficult to record it at an appropriate position with respect to the main signal.

The present invention has focused on this point, and has been devised for the purpose of facilitating writing to a predetermined position by making it possible to perform an index writing operation in a playback/pause state.

<Means for solving the problems> In order to achieve the above object, the magnetic recording and reproducing apparatus of the present invention has the following features:
By performing an index write operation in the playback/pause state, the tape is rewound a certain amount while counting control signal pulses from this playback/pause position, and then the control signal pulses are rewinded while the playback tracking servo is applied. The tape is fed forward while counting, and the required index information is recorded when the difference between the counted number during forward feeding and the counted number during rewinding reaches a set constant value. I try to do that.

<Function> The operator can freely select the playback/pause state in which the tape feed is stopped, for example in the case of a video cheap record, a still image is being played, and in this state index writing operations can be performed. Therefore, the writing position of the index information will not shift against the operator's will, and the index information will be accurately recorded at a predetermined position.

Moreover, the actual recording operation is performed while the tape is running in the forward direction with the playback tracking servo applied using the playback control signal and an oscillator inside the device, so the original function of the control signal is not impaired. .

<Embodiment> Next, an embodiment of a video tape recorder similar to that described in the above-mentioned Japanese Patent Laid-Open No. 57-15238 will be described with reference to the drawings.

The figure is a circuit diagram of the main part, 1 is the control circuit, 2 is the tape 3
4 is a capstan motor, 5 is a capstan motor control circuit, 6 is an amplifier for playback mode, 7 is an amplifier for record mode, 8 to 10 are electronics switch,
11 to 13 are monostable multivibrators, 14 is an OR date, and 15 is a group of keys including various operation keys such as play, pause, and index.

Now, when the device is in the playback state, the electronic switches 8 and 9 are switched to the playback (PB) side as shown in the figure by the mode switching signal (REC/PB) output from the control circuit 1, and the control head 2 The reproduction control pulse (PBCTL) picked up is outputted from the amplifier 6 via the switch 8. Here, when the pause key in the key group 15 is pressed, the control circuit 1 outputs an on/off signal (ONloFF) to the capstan motor control circuit 5 to control the rotation of the motor, and the capstan motor 4 stops. The device enters the play/pause state.

Next, when the index key is pressed, a forward/reverse signal (F/R) and an on/off signal (ONloFF) that control the rotational direction of the motor are output to the capstan motor control circuit 5, and the capstan motor 4 is rotated in the reverse direction. Then, the tape 3 starts running in the rewinding direction, and at the same time, the control circuit 1 outputs a playback control pulse (PB) output from the amplifier 6.
CTL). After this operation continues for, for example, 1.5 seconds, the capstan motor 4 is stopped by the on/off signal (ONloFF), and the count value a is obtained. Note that α is an integer.

Here, when the index key is pressed again, the capstan motor 4 starts rotating in the forward direction by the ON/OFF signal (ONloFF) and the forward/reverse signal (F/R), and the control circuit 1 outputs the output from the amplifier 6. Count down the control pulse (PBCTL). When the difference α-β between this countdown value β (integer) and the count value α at the time of rewinding described above reaches a preset value, the control circuit 1 issues a write command to write the index information. A signal (INDEX-WR) is output. This signal passes through the OR gate 14 to the electronic switch 1
0 to ON side, monostable multivibrator 11.
12 operates in synchronization with the playback control pulse (PBCTL) that has passed through the switch 10, and outputs an index information write signal (WR-IND) having a predetermined pulse width.
EX) is output from the monostable multivibrator 12 to the amplifier 7. At this time, the electronic switch 8 outputs the output signal (CTL-REC) of the monostable multivibrator 11.
), the write signal (WR-INDEX) amplified by the amplifier 7 is sent to the control head 2 via the switch 8, and the index information is recorded on the tape 3. .

When erasing the recorded index information, the tape is fed backwards and forwards in the same manner as in the case of recording above, and then an erasing command is sent from the control circuit 1 to erase the index information. Signal (INDEX-ER)
is output. This causes the index information erase signal (ER-INDE) to be output from the monostable multivibrator 13.
X) is output, and the signal of the control track of tape 3 returns to the control signal having the normal duty (that is, the index information is erased).

Note that VD is a vertical synchronization signal of the video signal, and in the normal recording mode, the mode switching signal (R
FC/PB) electronic switch 8.9 records (RF
Switching to the C) side, a regular mount roll signal based on a vertical synchronization signal (VD) is recorded on the control track 7 of the tape 3 in the same way as in a normal video tape recorder.

<Effects of the Invention> As is clear from the description of the above-mentioned embodiments, the magnetic recording and reproducing apparatus of the present invention is suitable for reproduction and reproduction when the tape is stopped running.
When in the pause state, start repeating to change the duty of the control signal, rewind and forward the tape, and record index information when the difference between the count-up value and count-down value of the pulse of the control signal reaches a certain value. That's what I do. Therefore, it is possible to record index information at a predetermined position without impairing the function of the track signal.

[Brief explanation of drawings]

The figure is a circuit diagram of a main part of an embodiment of the present invention.

Claims (1)

[Claims] 1. By changing the duty of the control signal recorded on the control track on the side edge of the tape,
In a magnetic recording/playback device equipped with a function to write required index information to a control track, by performing an index write operation in a playback/pause state, a fixed amount of tape is recorded from the playback/pause position while counting control signal pulses. Rewind, then feed the tape in the forward direction while counting the pulses of the control signal with the playback tracking servo applied.
A magnetic recording/reproducing device characterized in that required index information is recorded when the difference between the count number during forward forwarding and the count number during rewinding reaches a preset constant value. .