JPS61112482A - Magnetic picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable to obtain a still picture of odd number field and even number field selectively by selecting the first and second control signals obtained on the basis of rise-up of a reproduction control signal. CONSTITUTION:A reproduction control signal (a) obtained from a control signal head 3 is applied to a positive polarity detection signal 5 through an amplifier 4, and a signal (b) synchronous with rise-up is obtained. The signal (b) is im pressed respectively to a controller 10, a switching circuit 11 and a capstan servo circuit 9. On the other hand, a signal (c) corresponding to the angle of rotation of a capstan 2 and having frequency proportional to the rotational frequency is obtained from a frequency generator 6, and impressed to a counter 8 as a clock signal. When a predetermined count value N is attained, the count er 8 generates output (e), and signals (b) and (c) are switched in the switching circuit 11 basing on a control signal (k). Thus, reproduction of still picture of both odd number field and even number field is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a helical scan type magnetic recording medium in which a rotating magnetic head sequentially records one field of signals as one recording locus inclined with respect to the longitudinal direction of a magnetic tape. The present invention relates to a recording and reproducing apparatus (VTR), and is configured so that the recorded trajectory can be sequentially reproduced a plurality of times during reproduction.

Conventional configuration and its problems Conventionally, VTRs have two rotating magnetic heads.
As shown in Fig. 1, for example, the human head sequentially records the odd field signal as a trajectory a, and the B head records the even field signal as a trajectory, and also controls the signal synchronized with the rotational phase of the human head. The signals are recorded sequentially on the tape as signal C.

When obtaining a still image during playback, the capstan motor is stopped in phase synchronization with the rising edge of the playback control signal, and the magnetic tape is completely stopped and the trajectory &(, - is repeatedly played back and the still image is It is configured to obtain

Therefore, it was not possible to reproduce a still image of the other trajectory.Objective of the InventionThe present invention solves the above problems and is configured to be able to obtain a still image of either an odd field or an even field. This is what I am trying to do.

Structure of the Invention To achieve the above object, the present invention creates a first control signal that obtains a still image of the recording trajectory of one field at the rising edge of the reproduction control signal, and generates a first control signal synchronized with the rising edge of the reproduction control signal. The output of a frequency generator that generates a predetermined number of pulse signals according to the rotation angle of the capstan is counted sequentially, and the pulses generated when the pulses are counted up to a predetermined count value can be used to record the recording trajectory of the other field. A second control signal is used to obtain a still image, and by selecting all of the first and second control signals, still images of odd and even fields can be selectively obtained. It is something.

DESCRIPTION OF EMBODIMENTS FIG. 2 shows a block diagram of the main parts of the VTFt of the present invention,
FIG. 3 shows its operating waveform diagram.

In FIG. 2, 1 is a magnetic tape driven by a capstan 2, and 3 is a control signal head.

The reproduction control signal a reproduced by the control signal head 3 is sent to a positive signal detector 6 via an amplifier 4.
The signal bf synchronized with the rise of the control signal is obtained as its output.

This signal is connected to the controller 10° switching circuit 11's?, which is composed of a microcomputer, etc. and the capstan servo circuit 9. On the other hand, in response to the rotation angle of the capstan 2 that drives the tape 1, a signal of a frequency proportional to the rotation speed of the capstan 2 is obtained by the frequency generator 6. There is a proportional relationship between the number of pulses of the output signal of the frequency generator 6 and the amount of tape travel. The output C of this frequency generator 6 is applied via an amplifier 7 to a counter 8 as a clock signal.

The output C is also applied to a capstan servo circuit 9, and during normal reproduction, capstan control is performed using a conventionally known configuration so that the rotary head accurately scans the recording locus.

2.12 is a motor drive circuit.

The counter 8 starts the counter control output d from the controller 10 and generates an output e when the signal C reaches a predetermined count value N. This output is applied to the switching circuit 11. In this switching circuit 11,
According to the control signal k from the controller 10, the signal S to e is selectively switched and its output r2 is applied to the controller 1Q.

In addition, the controller 10 inputs to the ii'lJ counter 8,
A counter control signal g and a reset signal d that control the counting operation are applied.

Terminals 13 and 14 are input terminals to which are applied a normal playback reference signal for capstan drive during normal playback and a step playback reference signal for capstan drive during step playback. Accordingly, controller 1o
The servo circuit 9 is configured to be selectively switched and applied to the servo circuit 9 in response to a switching signal from the servo circuit 9.

Next, this operation will be explained.

During normal playback, the switching circuit 1S applies the normal playback reference signal applied to the terminal 13 to the capstan servo circuit 9 in response to a signal from the controller 1o. The capstan 2 is driven by a conventionally known means in response to the presence of a signal obtained from the reproduction control signal to perform reproduction.

During step playback, a step drive mode command signal shown in FIG. 3 is applied to the controller 10 from the terminal 16, and a step drive signal j is applied to the drive circuit 12 from the controller 1o.

In addition, the switching circuit 16 applies the step playback reference signal of the terminal 14 to all cabstan servo circuits 9 according to the signal, the tape is driven at a predetermined speed, and the playback control signal &
is obtained, and a signal responsive to this rising edge is obtained.

When starting to drive the steering wheel and knob, the switching circuit 11 presets the control signal as the signal b'f! : Since the signal is configured to be selected, the signal is output as the signal f. By applying this signal to the controller 10, after a predetermined period of time,
The step drive signal F becomes low level, the capstan 2 stops, and the tape stops. The stop position of the tape at this time is determined for the predetermined time so that an optimal still image can be obtained.6 After the step drive signal goes low, it goes back to high again after a predetermined time. level and the tape is driven. The predetermined time t is a period during which a still image is obtained.

On the other hand, the positive polarity signal of the playback control signal Suga controller 1
When applied to Q, the counter control signal g goes high and the counter 8 starts counting. This counter control signal g, as shown in FIG. This is an AND output of the step drive signal f and the signal g2 having the same waveform.

In other words, during the period when the tape is not running (the period when the capstan is not rotating), the count is completely stopped.
This prevents erroneous counting due to noise, etc. The counter 8 generates an output e when it has counted a predetermined number N, as shown in FIG. 3C'.

This signal e is applied to the controller 10 as a signal r via the switching circuit 11, and this signal causes the step drive signal to fall, the tape is stopped, and a still image is obtained.

At this time, the count N is set in advance so that an optimal still image can be obtained.

Further, it is configured such that a resect pulse k is applied to the counter 8 in synchronization with the signal e.

When the step drive signal (step drive signal) falls, it rises again after a predetermined time, the tape is driven, and when the playback control signal is played back, a still image is obtained by the above-described operation.

After that, repeat this operation for odd fields.

Still images are played back alternately in even-numbered fields.

Effects of the Invention As described above, according to the present invention, still images of odd and even fields can be sequentially reproduced.
When used to reproduce R, each field can be reproduced as a still image, making the analysis more reliable.

[BRIEF DESCRIPTION OF THE DRAWINGS] Figure ii is a diagram schematically showing a recording pattern on a tape of a tq helical scan type VTR; Figure 3 is a waveform diagram of the same operation. 1...magnetic tape, 2...capstan, 3...control head, 6...
... Frequency generator, 8... Counter;, 9...
...capstan servo, 10...controller,
11.15...Switching circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] Two rotating magnetic heads are used alternately to sequentially record one field of video signals into one recording locus inclined with respect to the longitudinal direction of the tape, and the rotational phase of one of the rotating magnetic heads is adjusted. A signal indicating the control signal is recorded on the magnetic tape as a control signal, and during playback, the running of the magnetic tape is stopped for a predetermined time in synchronization with the playback signal of the control signal, and in synchronization with the playback control signal. , sequentially counts the output of a frequency generator installed in a capstan that drives the magnetic tape, and when a predetermined count value is reached, the running of the magnetic tape is stopped again for a certain period of time, and each of the above A magnetic recording and reproducing device characterized in that a video signal of one field of a recording trajectory is sequentially reproduced as a still image.