JPS60176376A - Reproducing servo circuit - Google Patents

Abstract

PURPOSE:To obtain a reproducing picture with excellent quality not locked out even with the presence of dropout by detecting a timewise error of a reproducing synchronizing signal and controlling the revolution of a disc so as to be the same as that at recording. CONSTITUTION:A signal written in a magnetic disc 2 is reproduced by a magnetic head 3 and a reproducing circuit 4, the reproduced signal is inputted to a synchronizing separator circuit 5, from which a composite synchronizing signal A is separated and inputted to a timing pulse generating circuit 6. The timing pulse generating circuit 6 outputs a signal E of 0.5H interval in synchronizing with the reproducing signal even with the presence of dropout in the reproducing signal, the said signal E and a trapezoidal wave G are inputted to an S/H circuit 8 and a signal having a level in response to the phase shift of the composite synchronizing signal is extracted from the S/H circuit 8. This is compared with a reference phase at a comparator 10, an error output is fed to a motor drive circuit 12 and the revolution of the disc is controlled so as to be the same as that at recording.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a portable electronic still camera or the like that is integrally provided with a recording device using a rotating recording medium such as a magnetic disk. Regarding the reproduction servo circuit 1 for reproducing a still image corresponding to one field from the above-mentioned rotating recording medium on which one field worth of is recorded, more specifically, the rotation generated during recording of the rotating recording medium This invention relates to a reproduction servo circuit that corrects rotational unevenness during reproduction and obtains a reproduced still image signal with rotational unevenness compensated for. An electronic still camera system has been proposed in which one field or one frame of a still image signal is endlessly recorded on a disk (hereinafter simply referred to as a disk) and the still image is reproduced from the disk. In such electronic still camera systems, since the camera is held and operated by hand during recording, disturbance torque that disturbs the rotation of the disk, which should be driven at a constant rotation speed, is likely to occur. In order to correct the uneven rotation of the disk during playback, a playback servo is required to control the rotation using a playback synchronization signal.

By the way, in the electronic still camera system, if a disturbance torque occurs during recording, for example, in the case of field recording, one endless track has one field worth of 26
25T ((H represents one horizontal scanning period, so 26251
-I means 2625 water scanning signals) When the image signal should be recorded, it becomes 263H or 262H.
I end up becoming. That is, it is not necessarily guaranteed that the vertical synchronization signal VD (hereinafter referred to as VD) and the horizontal synchronization signal HD (hereinafter referred to as HD) are maintained in the relationship of VD:H 1:2625.

Although different from this electronic still camera, there is a VTR that records and plays back images and sound, and uses magnetic tape.

It has been known. Incidentally, the reproduction servo of a conventional VTR processes the reproduction signal VD and HD by comparing the phases with the reference VD and T (D), respectively.However, this method is similar to VT11'! to vD: HD=1:2
It is assumed that the relationship 625 holds true, but if it is applied to an electronic still camera system where the above relationship does not hold, not only will it not be possible to achieve satisfactory rotation control, but the rotation will become unstable. become. That is, VT
II? , the image signal for one field is recorded serially in the lengthwise direction of the 8x tape, so T
(Even if the distance (density) between D changes slightly, VD and T
(The numerical relationship with D is always maintained at 1:2625. However, in the case of a system such as an electronic still camera system that records one field of still images on one endless track, As mentioned above, the relationship between VD and I-ID is not necessarily constant due to fluctuations in the rotational speed during recording. The method to do this cannot be applied to Chemiko still camera system.

Therefore, if you do not want to use an electronic still camera system,
It is conceivable to control the disk rotation drive for reproduction by applying reproduction servo only or only to HD.

However, when only a VD is used, the playback servo is no different from comparing the phase of the signal generated by one pulse 'ff per one rotation of the disk with the reference signal (5); it simply rotates the disk at a constant speed. In the same way as controlling, it is impossible to correct rotational disturbances during recording and during reproduction.

Next, let us consider the case where reproduction servo is applied using only the reproduction HD. Here, as a recording/playback method for an electronic still camera, ■ A disk YX is rotated at 3400 rpm, and only one field signal is recorded on one endless track.When playing back, the one field signal V
D. How to create an odd/even field with a 5H delayed signal and a non-delayed signal, and ■Disk'k 3,60O
rpm, two endless tracks are used, odd and even fields are recorded on each, and during playback, the two tracks are played back alternately. There are three methods, one is to record both odd and even fields on one endless track, but each method compares the phase of the reproduced HD separated from the reproduced signal with the reference H'D and performs servo control. If the number of HDs is not 2625, the HDs will not connect properly at the switching point (odd/even field signal switching point or frame signal switching point), and this switching will occur every rotation during playback. As a result, the servo car locks out every time, causing the rotation to be disturbed, or it becomes impossible to lock it at all, making the reproduced image extremely unsightly.Furthermore, there may be dropouts somewhere on the recording track. In some cases, the HD is missing, and as in the case described above, the rotation may be disturbed or the lock may become impossible, causing the reproduced image to be lost.
<It's unsightly, and I'm L7.

[Summary of the invention]

The present invention eliminates the above-mentioned conventional drawbacks, and includes means for detecting a time error in a reproduced synchronization signal, and means for integrating an error signal detected by the means, and the integrated error signal is The above disk (rotating recording medium)
[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1st
In the figure, reference numeral 1 denotes a motor, which drives a magnetic disk 2, as is well known.This magnetic disk 2 is used by a small M electronic still camera, etc., which is integrally equipped with a recording device that uses the magnetic disk. One field of image signals is recorded for each rotation. Reference numeral 3 denotes a magnetic head, which reproduces signals from the magnetic disk 2 in a well-known manner.The reproduced signal from this magnetic head 3 is passed through a reproduction amplifier and a demodulation circuit, then to a reproduction circuit 4, and then to a synchronization separation circuit 5. A synchronization signal (a composite synchronization signal including at least a horizontal synchronization signal) is separated from the signal input to the synchronization separation circuit and reproduced by the synchronization separation circuit.

6 is a timing pulse generation circuit that receives the Doi synchronization signal and generates a timing pulse, and 7 is a timing pulse generation circuit that generates a timing pulse from the timing pulse generation circuit.
A trapezoidal wave generating circuit 8.9 generates a trapezoidal wave by sampling the level of the trapezoidal wave from the trapezoidal wave generating circuit into the pulse from the timing pulse generating circuit 6, and kneading.
10 is an integrating amplifier that integrates the outputs of these sample and hold circuits 8 and 9; 11 is a frequency generator (hereinafter referred to as (abbreviated as FG), 12 is a first motor 1 controlled by the output of the integrating amplifier 10 or the output of F011.
This is a motor drive circuit that drives the. Is this motor drive circuit the FG signal from F'Gi1 above? For example, if the speed is detected using the above-mentioned FG signal and the speed is out of a predetermined speed range, If control is to be performed using the Ll'G signal, or if the reproduction signal is not output, FG sub-control is performed, and when a reproduction signal is obtained, the reproduction servo is applied to the output from the integral amplifier 10. FIG. 2 is a block diagram showing details of the timing pulse generation circuit B, which is configured so that the magnetic disk 2 is controlled at a constant speed even when no reproduction signal is obtained. , code 13~
18 is a non-retriggerable mono multivibrator (hereinafter referred to as "non-retriggerable mono multivibrator").

These MMs are triggered by the falling edge of the input signal. 19 has a period of 0.5H and a pulse width T! The astable multivibrator is reset by the rising edge of the input signal, and during this reset, the first pulse is 05T (configured to appear later). .

Reference numeral 20 indicates an inverter, and reference numerals 21 and 22 indicate OR gates. Note that the pulse width of the output of the astable multivibrator 19 of MM13 to 18 mentioned above is created digitally by dividing the reference clock, and the pulse width may not change due to temperature, etc. do not have.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be explained using the timing chart shown in FIG. The signal is reproduced by the circuit 4, and the reproduced signal is input to the synchronization separation circuit 5, which separates the composite synchronization signal A, which is input to the above-mentioned timing pulse generation circuit 6Ic. The above-mentioned MM 13 constituting this timing pulse generation circuit 6 has a pulse width of T.

(202~[1,3)J) and MM14
From L-1 + P 8Δn) Tachimoto ThX 'l'l Moe\
L A, Z Feng: A pulse with a pulp width T2 (IH) is output (signal C) by cooperation, and the pulse of this signal C and the signal whose phase is inverted by the innocoducer 20 of the above signal A. is input to the OR gate 21, the output of the OR gate 21 is input to the astable multivibrator 19, and the astable multivibrator 11 is set based on these signals. As a result, the astable multivibrator 19 has an interval of T, +0.5H between the signals C.
(If it is shorter than 0.7~[1,8T()), it will be reset, so the output will be like D, and the interval of signal C will be T1
+0.5'H or more, fill in the space between the signals C at 05) 1 interval, υ, and OR gate 22 to OR't the p signal port and the signal DO't, the signal Eo) with the 05H period signal), the reproduced signal is an even field signal.

Regardless of whether it is an odd field signal or a frame signal, or even if there is a dropout in the reproduced signal, the signal E will be a signal with an interval of 0, 5) 1, synchronized with the reproduced signal.

In the embodiment of the present invention, the signal Ev is used to control the magnetic disk 2.
This method of control is described in Japanese Patent Application No. 126860/1985, which was previously filed based on the invention of the inventor of Wood, as a speed control circuit free from temperature drift, etc.
This method is used.

The signal E is input to the MM15, and when this input falls, the triggered MM15 outputs a pulse with a pulse width T3. The MM16, triggered by the falling edge of this pulse at 9, outputs a pulse with a pulse width T4, and as a result, the MM16 outputs a pulse with a pulse width T4 to Tsl at the falling edge of the signal E. This output is the signal F
Then, the trapezoidal wave generating circuit 7 generates a trapezoidal wave GY. This signal is also input to the MM17, and when this input falls, the triggered MM17 outputs a pulse with a pulse width T5. MM whose falling edge of this pulse is triggered by many times
18 outputs a pulse with a pulse width T2, resulting in MM
18 outputs a pulse with a pulse width T2 with a delay of T after the falling edge of the signal F (signal H\T,+T,
The above pulse widths are set so that +T4+T='0.5H.

The above trapezoidal wave G and signal E are input to a sample-and-hold circuit 8, and the level of the trapezoidal wave G at the position of signal E is sampled. Since the signal E at this time is formed by the falling edge of the composite sync signal A, the sampled trapezoidal wave G is the same as the composite sync signal A.
The sample-and-hold circuit 8 outputs a signal according to the phase shift of the composite synchronization signal A with respect to the period of 0 and 5H, which is the period of the astable multivibrator 19. In other words, a signal at a higher level, that is, an output obtained by converting the signal E Y F-V is obtained. The above trapezoidal wave G and signal H are input to a sample-and-hold circuit 9, and the level of the trapezoidal wave G at the position of signal H is sampled. The phase relationship between this trapezoidal wave G and signal H is M
There is a predetermined relationship determined by the output pulse width of M17.18, and the output of the sample and hold circuit 9 should be output when the period of the signal E becomes 0.5T. The outputs of the sample-and-hold circuits 8 and 9 are both input to the integrating amplifier 10, and the difference between these two outputs is integrated into the integrating amplifier, and the output of the integrating amplifier 10 is set to the voltage. The signal is input to the motor drive circuit 12.

By controlling the rotation of the motor 1, that is, the magnetic disk 2, by this motor drive circuit 12, that is, the voltage that integrates the above two output differences, the signal E is 0.5T (
The IQ, that is, the period of the reproduction HD is set to the basic 1H so that the period of
controlled to be the same as the period. In the embodiment of the present invention, the speed error was converted to voltage and the output passed through the integrating amplifier was used for control 7, but it is possible to convert the speed error into a digital value and integrate the value with a counter. Each part may be digitized. Furthermore, in the embodiment of the present invention, the temperature drift of the speed control circuit is corrected, and the speed deviation due to the load fluctuation of the magnetic disk is also eliminated by installing an integrating amplifier, so that it is possible to correct the temperature drift of the speed control circuit. It is possible to provide a regenerative servo circuit with equivalent accuracy.

〔Effect of the invention〕

As described above, this invention uses a recording device h'' using a rotating recording medium such as a magnetic disk, in which one field or frame of an image signal is recorded every rotation by a compact electronic still camera or the like that is integrally provided. In the apparatus for reproducing one field or frame of still images Y from the above-mentioned rotating recording medium, there is a means for detecting a time error in the reproduction synchronization signal based on the reproduction horizontal synchronization signal or the reproduction composite synchronization signal (e.g., timing pulse generation). circuit 6, trapezoidal wave generating circuit 7, sample-and-hold circuit 8.9, etc.), and means such as an integrating amplifier for integrating the error signal detected by the means. Due to the error signal, the rotation of the above-mentioned rotating recording medium is made to rotate at the same speed as during recording.Since UW is performed at different speeds in step 5, there is no lockout and dropout compared to the conventional method (compared to phase control). You can obtain high-quality playback images that do not lock out even when

[Brief explanation of the drawing]

Is Figure 1 an example of this invention? The block diagram of the playback servo circuit shown in Figure 2 is the details of the main part of the one in Figure 1. The block diagram shown in FIG. 6 is a time chart for explaining the operation of the device shown in FIG. 1: Motor, 2: Magnetic disk, 6: Magnetic head, 4:
Reproduction circuit, 5: Synchronization separation circuit, 6: Timing pulse generation circuit, 7: Trapezoidal wave generation circuit, 8.9: Sample and hold circuit, 10: Integrating amplifier, 13=-18: Non-11 triggerable mono multivibrator, 19: Astable multi-pie break. Agent Patent Attorney Sanro Kimura

Claims (1)

[Claims] In a playback device for a small electronic still camera integrally provided with a recording device using a rotating recording medium, means for detecting a temporal error in a playback synchronization signal based on a playback horizontal synchronization signal or a playback composite synchronization signal; and means for integrating the detected error signal, and controls the rotation of the rotary recording medium based on the integrated error signal.
A regenerative servo circuit characterized by: