JPS62154262A - Picture recorder and reproducing device - Google Patents

Abstract

PURPOSE:To shorten a rotating phase changing time of a magnetic-sheet driving motor when a magnetic head moves from a track to another track, by directly controlling the producing timing of vertical synchronizing signals by using tack signals produced synchronously to the rotating of the motor at every rotation of the motor. CONSTITUTION:During track access operations at the time of reproduction, a track feeding signal A is outputted from a system control circuit 11 and inputted to a vertical synchronism resetting circuit 12. Then a gate signal generator 121 opens and AND circuit 123 for a previously fixed period T and tack signals E from a rotating position detector 5 are inputted to a vertical synchronizing signal generator 6. The tack signals E inputted to the generator 6 forcedly reset the generator 6 and make vertical synchronizing signal C outputted from the generator 6 synchronous to the tack signals E. Since the phases of the tack signals E can forcedly be matched to the phases of the vertical synchronizing signals C while the phases of the tack signals E fluctuate even when a change in the rotating phase of a sheet motor 1 takes place due to the movement of a magnetic head from a track to another track and the phases of the tack signals E fluctuate, the time required for pulling-in the phase can be made shorter.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an image recording and reproducing device that records or reproduces a video signal on a rotating disc-shaped magnetic recording medium using a ζn-type head. Yes, for more details,
During playback, when the magnetic head moves radially over the recording medium, this causes load fluctuations on the motor that rotates the recording medium, and the rotational phase of the motor fluctuates. The present invention relates to such an image recording and reproducing apparatus equipped with means for minimizing the number of images.

[Background of the invention]

In video equipment, a servo circuit for a motor that rotationally drives a recording medium has conventionally included a speed control system and a phase control system, as disclosed in Japanese Patent Laid-Open No. 58-22588. A hunting head is brought into contact with the track surface on a flexible magnetic sheet, a still image is recorded on each track, and m
The resulting image recording and reproducing apparatus also has a similar control system.

In such devices, when the magnetic head is moved from track to track on the sheet, the contact force between the magnetic head and the magnetic sheet changes, which temporarily reduces the load on the motor that rotates the magnetic sheet. , the operating point of the one-phase speed control system changes, and the phase lock position fluctuates, causing a phenomenon in which the rotational phase of the motor shifts. However, no particular consideration has been given to this point in the past.

However, this problem is particularly problematic when so-called quick shooting is performed, such as in an electronic camera, in which several still images are sequentially recorded per second on each track by sequentially moving a magnetic head. That is, as mentioned above, when the magnetic head is moved to the next track, the rotational phase of the motor that rotationally drives the magnetic sheet changes, so in order to record the video signal at the correct position on the magnetic sheet, it is necessary to This must be done after the fluctuations have subsided and the magnetic sheet has returned to its correct rotational speed.

This takes about 0.4 seconds, and the continuous shooting speed is only about 2 images per second, which is not a fully satisfactory performance of an electronic camera.

In addition, in this image recording and reproducing device, an additional code signal for distinguishing between a field image and a frame image is multiplexed onto the video signal and recorded at a specified position on the track of the magnetic sheet, and this signal is read out during playback. The system distinguishes between field images and frame images, and automatically switches the playback operation. However, in this case as well, if there is a change in the rotational phase of the motor, the readout position of the additional code signal will shift and it will not be possible to read it out correctly. It is not possible to determine whether

This means that when moving tracks, it is not immediately clear whether to send one track (for field images) or two tracks (for frame images).
It takes a long time to access the track, and it is not possible to obtain satisfactory performance from an operational point of view.

There is also a visual problem in that the playback screen is shaken while the rotational phase of the motor is changing.

As mentioned above, fluctuations in the rotational phase of the magnetic sheet drive motor accompanying the track movement of the magnetic head on the magnetic sheet affect the operating performance of the image recorder 25 playback device both during recording and during playback. Therefore, there is a demand for reducing the amount of fluctuation in the motor rotational phase by suppressing the amount of variation in the rotational phase of the motor, but this application specifically aims to solve this problem during playback. It is said that

[Purpose of the invention]

As already stated, an object of the present invention is to reduce the amount of fluctuation in the rotational phase of the recording medium drive motor accompanying the track movement of the magnetic head during reproduction by an image recording and reproducing apparatus, and to reduce the amount of time during which the phase is fluctuating. It is an object of the present invention to provide an image recording and reproducing device equipped with a means for shortening the length.

[Summary of the invention]

In the image recording and reproducing apparatus, during reproduction, a vertical synchronizing signal is generated and this is used as the reference timing 1g of the rotational phase of the recording medium (magnetic sheet) drive motor. ,
The generation timing of the vertical synchronization signal is directly controlled by using a tack signal generated in synchronization with each rotation of the magnetic sheet drive motor, thereby shortening the rotational phase fluctuation time of the magnetic sheet drive motor. did.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system block diagram showing one embodiment of the present invention.

In the figure, 1 is a seat drive motor (hereinafter sometimes simply referred to as the seat motor) that rotates the magnetic sheet.
, 2 is a motor drive circuit for driving the seat motor 1, 3 is a frequency generator (abbreviated as FG) for detecting the rotation speed of the seat motor, and 4 is a frequency generator (abbreviated as FG) for detecting the rotation speed of the seat motor 1. By comparing the output of FG 3 with a reference speed, A speed control circuit 5 outputs a speed error signal so that the rotational speed of the seat motor 1 becomes constant at the reference speed, and 5 is a one-rotation circuit for detecting the rotational position of a magnetic sheet (not shown) driven by the seat motor 1. 6 is a vertical synchronizing signal generator; 7 is the generator 6;
A phase control circuit 8 outputs a phase error output so that the phase difference between the vertical synchronization signal from the rotational position detector 5 and the tack signal from the rotational position detector 5 becomes zero; an adder 9 that adds the phase error signal from the phase control circuit 7 and applies it to the seat motor drive circuit 2;
1 is a pulse motor that serves as a drive source for a head movement mechanism (track movement mechanism) (not shown) using a feed screw, cam, etc.;
0 is a pulse motor drive circuit, 11 is a system control circuit that performs various controls of the system including track feed control, 12 is a vertical synchronization reset circuit provided according to the present invention, and gate signal generator 121. Delay circuit 12
2. It is composed of an AND gate 123.

FIG. 2A is a waveform diagram of signals (indicated by symbols A to E) of each part in the system block diagram of FIG. 1 in conventional operation, and FIG. 2B shows waveforms after improvement according to the present invention.

First, with reference to FIG. 1 and FIG. 2A, the circuit operation when the present invention is not implemented, that is, when the vertical synchronization reset circuit 12 does not operate, will be described.

In the track access operation during reproduction, first, the system control circuit 11 outputs the track feed signal A. As a result, several pulse trains are output from the pulse motor drive circuit IO to rotate the pulse motor 9 as a head drive mechanism, and move the magnetic head (not shown) to the next track (inner or outer direction of the magnetic sheet). let

The time required for this truck movement is approximately 15 m5.

During this time, the load on the seat motor 1 increases as shown in B, causing pulse-like load fluctuations.

This slows down the rotation speed of the seat motor l, so
The phase of the tack signal E output from the rotational position detector 5 lags behind the vertical synchronization signal C output from the generator 6, and the phase error signal increases.

The phase control circuit 7 controls the phase error signal to zero, but due to the response characteristics of the phase control system, it cannot respond quickly. Moreover, it takes time for the rotational phase of the seat motor 1 to match the phase of the vertical synchronization signal and for the phase to be pulled in.

Next, the circuit operation when the vertical synchronization resent circuit 12 operates will be described with reference to FIG. 1 and FIG. 2B.

In track access operation during playback, a track feed signal A is output from the system control circuit 11,
Until the load on the seat motor 1 increases as shown in B,
There is no difference from conventional operation.

However, this time, the track feed signal A is input to the vertical synchronization reset circuit 12.

Then, the gate generator 121 outputs the gate signal F for a predetermined period T, and the AND circuit 123 is opened during this period. For this reason, the tack signal E from the rotational position detector 5 is inputted to the vertical synchronization signal generator 6 through the anti-game 1-123 after being delayed by the delay circuit 122, and the tack signal E is forcibly generated. The vertical synchronizing signal C outputted from the generator 6 is synchronized with the tack signal E by resetting the generator 6 at the same period.

In this way, the seat motor l is driven by the truck f.
Even if a rotational phase fluctuation occurs and therefore the phase of tie No. 3 E fluctuates, the phase of the tack signal E can be forcibly matched to the phase of the vertical synchronization signal C during that time, so the phase pull-in is prevented. The time required can be reduced to approximately half that of the conventional method.

In addition, in FIG. 2B, the gate signal F is shown to be generated simultaneously with the track feed signal A, but the gate signal F
If it is made to occur at a point earlier than the track feed signal A, the effect can be further enhanced.

In addition, in the case of an electronic camera, the generator 6 of the vertical synchronization signal, which is the rotation reference timing signal of the seat motor 1, is equipped with a synchronization generator that generates a necessary synchronization signal for the camera. Just use it.

FIG. 3 is a block diagram showing the configuration when the present invention is applied to an electronic camera. In the figure, an optical imaging device 1
3, the optical image is electrically converted and a video signal is obtained via the imaging circuit 14. A synchronization signal necessary for the imaging circuit 14 is generated from a synchronization signal generation circuit 15. The synchronization signal generation circuit 1
5 generates a highly accurate synchronization signal using a crystal oscillator 16. The present invention is implemented by adding the already explained vertical synchronization reset circuit 12 to this.

FIG. 4 shows the configuration of a still image recording and reproducing device or a reproduction-only device that does not have an imaging section. For the reference signal during recording, the changeover switch 18 is set to the R side, and a vertical synchronization signal is obtained from the externally inputted video signal by the synchronization separation circuit I7. During reproduction, the selector switch 18 is set to the P side, and the synchronization generation circuit 15 supplies the signal. The present invention is implemented by adding a vertical synchronization reset circuit 12 to this synchronization signal generation circuit 15.

FIG. 5 is an operational waveform diagram in the case of random access for sending multiple tracks at once.

The phase error ID' is saturated after several tracks have been fed and becomes a constant amount, but due to load fluctuations when track feeding is finished, phase fluctuations occur again. At this time, the above-mentioned reset operation is performed, but since the amount of phase fluctuation is larger than that during one-track feeding, the phase pull-in time is also longer than when one-track feeding is performed.

In order to improve this problem, the tack signal E is used to perform the reset operation continuously. This causes phase fluctuation D#
Since it settles after the first few tracks are fed, the amount of phase fluctuation at the end of track feeding is small, and the phase pull-in time can be shortened even when many tracks are fed.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to reduce the amount of variation in the rotational phase of the sheet motor that occurs when the magnetic head tracks, and the time during which the phase is varied is also shortened. The track access speed can be increased, improving operability.

[Brief explanation of drawings]

FIG. 1 is a system block diagram showing an embodiment of the present invention;
Fig. 2A is a waveform diagram of the signals of each part in the system block diagram of Fig. 1 in conventional operation, Fig. 2B is an operational waveform diagram after the improvement according to the present invention, and Fig. 3 is a case where the present invention is applied to an electronic camera. FIG. 4 is a block diagram showing an embodiment of the present invention applied to a still image recording and reproducing device that does not have an imaging section. FIG. FIG. Explanation of symbols 1... Seat drive motor, 2... Seat motor drive circuit, 3... Frequency generator FC14... Speed control circuit, 5... Rotational position detector, 6... Vertical synchronization Signal generator, 7... Phase control circuit, 8... Adder, 9
... Pulse motor, 10... Pulse motor drive circuit, 11... System control circuit, 12...
- Vertical synchronization reset circuit, 15... synchronization signal generation circuit. Agent Patent Attorney Akio Namiki Ill Ill Utsuju IFI term t-/To times S coma #2Azuku2as Tomi 31 Figure 4 Tomi 55! l

Claims (1)

[Scope of Claims] 1) A motor that rotationally drives a disc-shaped magnetic recording medium, a rotational speed control circuit that controls the rotational speed of the motor to be kept constant, and an arbitrary specific rotation on the rotating recording medium. a rotational position detection means for outputting a signal indicating the position as a tack signal each time a position is detected; a vertical synchronization signal generation means to be a rotation reference timing signal of the motor; and a tack signal from the rotational position detection means. a phase control circuit for controlling the rotational phase of the motor so as to match each phase of the vertical synchronizing signal from the generating means; and a magnetic head for recording or reproducing a video signal on the recording medium. a head moving mechanism for moving the magnetic head along the radial direction on the magnetic recording medium, the head moving mechanism moving the magnetic head along the radial direction on the magnetic recording medium; In the image recording and reproducing apparatus, in which a video signal is recorded on the track or reproduced from the track while moving, when the magnetic head is moved by a head moving mechanism during playback, the motor is moved along with the movement. gate period setting means for setting a predetermined period including at least a period in which load fluctuation occurs during the gate period; and during the set gate period, resetting the vertical synchronization signal generation means using the tack signal; An image recording and reproducing device comprising: reset means for synchronizing a tack signal and a vertical synchronization signal.