JPH05244547A - Video recording and reproducing device - Google Patents

Abstract

PURPOSE:To suppress deterioration in picture quality caused by dubbing in a video equipment such as a still video camera, that is, to reduce jitter. CONSTITUTION:Not only speed servo but also phase servo is implemented for a reproduction side (A). The phase servo is implemented by using a phase control signal VD outputted from an oscillator 4a and a PG signal and the signal VD is sent to a recorder side (B) via a path L and the sent VD signal is inputted to a rotary control means 3b at the recorder side (B) and phase control is executed by using the signal VD as a reference signal. The signal VD is a signal having a period equivalent to one revolution of floppy disks 1a, 1b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for reducing jitter in a video recording / reproducing apparatus (such as a magnetic disk or an optical disk) in which jitter (a phenomenon in which an image shakes and deteriorates image quality) is likely to occur during dubbing. Related to technology for reducing jitter.

[0002]

2. Description of the Related Art FIG. 5 shows an example of a basic form when performing dubbing using a still video. The A side is the reproducing side, and the B side is the recording side (a normal still video can perform both recording and reproducing, but is shown in two for convenience of explanation).

On the reproducing side, basically, a floppy disk 1a which is a recording medium, a motor 2a, a rotation control means 3a,
Oscillator 4a, system controller (syscon) 5a,
It has a reproduction amplifier 6 and a reproduction signal processing 7.

The track pattern of the floppy disk 1a is standardized as shown in FIG. 6, but since the phase control to satisfy this standard may be performed on the recording side (B side), in principle the speed is set on the reproducing side. Only control is required.
This speed control is performed using an FG signal (a signal indicating the number of rotations of the motor that rotationally drives the disk) and a signal obtained by dividing the subcarrier signal _fsc (3.58 MHz) from the oscillator 4a. Even if phase control is not performed in this way during dubbing, the signal from the head can be amplified and reproduced on a monitor device (not shown) if the disk rotation speed does not differ significantly from the reference rotation speed. It suffices that reproduction processing can be performed as a level signal, and there is no particular problem with reproduced video.

On the other hand, the recording side (B side) is basically a floppy disk 1b, a motor 2b, a rotation control mechanism 3b,
Oscillator 4b, system controller (syscon) 5b,
It has a phase signal processing means 8, a sync separation means 9, and a recording amplifier 10.

When dubbing the reproduced video signal, it is necessary to record the video signal so as to satisfy the above-mentioned standard of FIG. 6 (that is, from the leading edge of the vertical synchronizing signal of the recorded video signal to 7).
It is necessary to record such that the center of the PG yoke is located at the position of H ± 2H), and for this reason, it is necessary to perform the phase control in parallel with the speed control. This phase control is performed by the phase of the vertical synchronizing signal (V _SYNC ) separated from the video signal sent from the reproducing side and the PG obtained from the PG yoke.
This is performed by matching the phase of the signal (one pulse is output for one rotation of the disk) by phase negative feedback control. The above configuration is the same for the normal recording of the external video signal.

[0007]

When reproducing a video signal, high-precision control is performed as described above.
Even so, some rotation unevenness (jitter) may occur and appear as unevenness in the time axis direction of the video signal. On the recording side, a synchronizing signal is separated from a reproduced video signal containing such a jitter and used as a signal for rotation control. Therefore, the rotation of the recording floppy disk 1b is affected by the original jitter and is displaced. Occurs. Usually, when a signal having jitter is used as a servo reference, even larger jitter occurs.
Therefore, in reality, the recording video signal having the jitter is recorded on the recording medium having the larger jitter. When the signal recorded in this way is reproduced and displayed as a still image, disturbance of vertical synchronization and horizontal synchronization causes, for example, a part of a straight line in the vertical (vertical) direction to be displayed in a bent state, resulting in poor image quality. Resulting in.

The present invention has been made in view of these problems, and an object thereof is to suppress deterioration of image quality due to dubbing (that is, reduce jitter).

[0009]

The present invention according to claim 1 executes speed control and phase control with reference to a signal from an internal oscillator when reproducing from a recording medium during dubbing, It is characterized by comprising rotation control means for controlling the rotation of the recording medium and signal sending means for sending the signal from the oscillator to the recording side device together with the reproduced video signal.

According to a second aspect of the present invention, there is provided sync signal replacement means for replacing only the vicinity of the vertical sync signal of the reproduced video signal reproduced from the recording medium for dubbing with the vertical sync signal from the built-in oscillator. It is characterized by

According to a third aspect of the present invention, when recording a video signal on a recording medium during dubbing, speed control and phase control are executed with reference to a signal sent from an internal oscillator of a reproducing side device. However, it is characterized by having a rotation control means for controlling the rotation of the recording medium.

[0012]

When dubbing, on the reproducing side, speed control and phase control of the recording medium are performed based on a signal (pulse signal) output from a common oscillator, while the pulse signal output from this oscillator is recorded side. Also, the recording side uses the basic pulse signal (a signal that does not include jitter) to control the speed and phase of the disc so that it is not affected by the jitter on the playback video signal. Accurate synchronization control can be performed (the inventions of claims 1 and 3). As a result, dubbing can be performed in a state where the characteristics of the rotation control system of the recording-side device can be maximized, and recording can be performed at the same level as that of the normal recording of a video signal without jitter.

Further, the signal from the oscillator on the reproducing side is not directly sent to the recording side, but is added to the reproduced video signal by partial replacement so that there is no jitter added in the form of synchronous separation on the recording side. By taking out the synchronizing signal and using it for controlling the disc, similarly, the deterioration of the image quality can be prevented (the invention of claim 2).

[0014]

Embodiments of the present invention will now be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing the configuration of an embodiment of a video recording / reproducing apparatus of the present invention.

A feature of this embodiment is that not only the speed servo but also the phase servo is performed on the reproducing side (A). This phase servo is performed by using the phase control signals VD and PG output from the oscillator 4a. The signal VD can be sent to the recording side (B) via the path L, and the VD sent from the recording side (B)
A signal is input to the rotation control means 3b, and the phase control is performed using this signal VD as a reference signal. The signal VD is a signal having a cycle corresponding to one rotation of the floppy disks 1a and 1b.

An example of the structure of the rotation control means 3a, 3b is shown in FIG. Velocity servo system includes a voltage amplifying circuit 20a for amplifying the FG signal, a waveform shaping circuit 21a, FG signal and the oscillator 4a is waveform-shaped, a speed comparator 22 for comparing the f _sc from 4b, the speed comparator It is composed of a voltage amplifier 24a that amplifies the output of 22, a low pass filter 25, and a power amplifier 26.

The phase servo system includes a voltage amplifier circuit 20b for amplifying the PG signal, a waveform shaping circuit 21b, and a phase comparator 23 for comparing the waveform-shaped PG signal and the VD signal.
And a voltage amplifier 24b for amplifying the output of the phase comparator 23,
It is composed of a low-pass filter 25 and a power amplifier 26.

[0019] Incidentally, the FG signal instead of comparing the f _sc signal at a speed comparator 22 of the speed servo system, was set in a semi-fixed resistor V _{R (in} the figure, indicated by dotted lines) and internal capacitor (not shown) It is also possible to adopt a configuration in which the output signal (instead of f _sc ) of a simple oscillator is compared with the FG signal. This is because the phase control signal and the speed control signal are always added and fed back to the motor, so that the frequency of the reference signal for speed control does not require particularly high accuracy after the phase lock.

As described above, in the present embodiment, during dubbing, in the reproducing system, not only the speed control of the disk rotation but also the phase control based on the signal VD having a cycle corresponding to one rotation of the disk from the oscillator is used as a reference. Done, in the recording system,
The phase of the disk is controlled based on the VD signal sent. Therefore, since the recording side and the reproducing side use the same reference signal from the oscillator to control the rotation of the disk, the rotation on the recording side is not influenced by the jitter on the reproducing side. Further, the present embodiment can be realized on the reproduction side by only a simple change of adding a phase control system using the PG detection signal.

(Embodiment 2) FIG. 3 is a diagram showing a configuration of a second embodiment of the present invention. In the above embodiment, the reproduction function and the recording function are shown separately for the sake of easy understanding, but in most cases, they are actually integrated, and the present embodiment has such a reproduction / recording function. 1 illustrates a configuration example of a body still video camera.

In this embodiment, two switches (SW1,
SW2) is provided and the playback mode /
The recording mode can be switched, and the SW2 is used to input the reference signal VD for phase control at the time of recording / reproducing to the rotation control means 3 or the vertical synchronizing signal V _sync separated by the synchronizing separation circuit 9. Input can be switched.

The states of the switches in the respective operation modes (states) are described in a table form in the figure. In the dubbing state at the time of recording, SW1 is connected to the b side and a video signal is input. Further, SW2 is connected to the b side, and a VD signal is input from the outside. The rotation phase of the disk is this VD
It is controlled based on the signal. Further, in the normal recording mode, that is, in the case where a video signal such as a TV broadcast whose time axis fluctuation can be almost ignored can be recorded, the vertical synchronization signal V _sync separated from this video signal is used as a reference,
SW2 is connected to the b side. Also, during reproduction, SW1 is switched to the side a, and SW2 is connected to C to synchronize the phase with the signal from the oscillator 4 and send the same signal to the recording device side during dubbing VD.

As described above, in the reproduction / recording integrated device, the jitter can be reduced with almost no change in the configuration.

(Embodiment 3) FIG. 4 is a diagram showing the configuration of a third embodiment of the present invention. The feature of this embodiment is that the vertical synchronizing signal VD from the oscillator 4 is taken out for the phase control of the rotation, and this VD signal is replaced with the vertical synchronizing portion of the reproduced video signal. In this way, the jitter of the reproduced video signal itself does not change, but the vertical synchronization signal _{Vsync which} is synchronously separated on the recording side has no jitter, and the jitter can be reduced in the recording system. According to the configuration of this embodiment, unlike the case of the above-described embodiment using the VD signal, it can be realized by changing the configuration of only the reproducing side,
It is convenient.

Instead of replacing only the vertical synchronizing signal, the composite synchronizing signal can be replaced. In this case, the configuration is complicated, but the same effect can be obtained.

Although the present invention has been described above by taking a still video camera (system) as an example, the present invention is not limited to this, and can be widely applied to video devices that generate jitter.

[0028]

As described above, in the inventions of claims 1 and 3, the speed control and the phase control of the recording medium on the reproducing side during dubbing are performed by a signal (pulse signal) output from a common oscillator. ), While sending the pulse signal output from this oscillator to the recording side as well,
On the recording side, the basic pulse signal (signal that does not include jitter) is used to control the speed and phase of the disc, ensuring accurate synchronization without being affected by the jitter on the reproduced video signal. There is an effect that can be controlled. Therefore, dubbing can be performed in a state where the characteristics of the rotation control system of the recording side device can be maximized, and recording can be performed at the same level as normal recording of a video signal without jitter.

According to the second aspect of the invention, the signal from the oscillator on the reproducing side is not directly sent to the recording side, but is added to the reproduced video signal by partial replacement, and synchronization separation is performed on the recording side. By taking out the jitter-free synchronizing signal added in step 2 and using it for disk control, the effect of preventing deterioration of image quality can be similarly obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing a specific configuration example of rotation control means 3a and 3b in FIG.

FIG. 3 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional example.

FIG. 6 is a diagram showing a track pattern of a floppy disk in a still video camera.

[Explanation of symbols]

 1a, 1b Floppy disk (recording medium) 2a, 2b Drive motor 3a, 3b Rotation control means 4a, 4b Oscillator 5a, 5b System controller 6 Reproduction amplifier 7 Reproduction signal processing circuit 8 Recording signal processing circuit 9 Sync separation circuit 10 Recording amplifier A reproduction Side (dubbing) B Recording side (dubbing)

Claims (3)

[Claims] 1. Rotation control means for controlling the rotation of a recording medium by executing speed control and phase control based on a signal from an internal oscillator when reproducing from a recording medium during dubbing, A video recording / reproducing apparatus comprising: a signal transmitting means for transmitting a signal from an oscillator together with a reproduced video signal to a recording side device. 2. A video signal having sync signal replacement means for replacing only the vicinity of the vertical sync signal of the reproduced video signal reproduced from the recording medium for dubbing with the vertical sync signal from the built-in oscillator. Recording / playback device. 3. When recording a video signal on a recording medium at the time of dubbing, speed control and phase control are executed with reference to a signal sent from an internal oscillator of an apparatus on the reproducing side to rotate the recording medium. A video recording / reproducing apparatus having a rotation control means for controlling the.