JPH0628769A - Video disk player - Google Patents

Abstract

(57) [Abstract] [Purpose] NTSC video disc and MUSE
(EN) Provided is a video disc player which is compatible with a VCR type video disc and has a simplified configuration. [Structure] A common spindle motor 21 is provided for both types of video disks VD. The frequency dividing circuit 63, the phase comparing circuit 65, and the comparison output V65 of the phase comparing circuit 65.
Is provided. NTSC
At the time of reproducing the disc VD of the system, the synchronization signal PBHN included in the reproduced video signal SNT and the reference signal REFHN are supplied to the phase comparison circuit 65 to servo-control the rotation of the spindle motor 21. MUSE video disc V
At the time of reproducing D, the reproduced pilot signal SP is supplied to the frequency dividing circuit 63 and frequency-divided into a frequency-divided signal S63 having a frequency close to the frequency of the synchronizing signal PBHN, and the frequency-divided signal S63 and the reference signal REFH2M are divided. It is supplied to the phase comparison circuit 65 to servo-control the rotation of the spindle motor 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video disc player.

[0002]

2. Description of the Related Art NT is the current standard television system.
There are SC method, PAL method, SECAM method, etc.,
In the case of the NTSC system, the standard is horizontal frequency fHN = 4.5 MHz / 286 = approximately 15.734 kHz vertical frequency fVN = 2fHN / 525 = approximately 59.94 Hz aspect ratio = 3: 4.

A high-definition television system has been developed as a television system of higher quality than the NTSC system. The standard is vertical frequency fVM = 60Hz horizontal frequency fHM = 1125 × fVM / 2 = 33.75 kHz aspect ratio. = 9: 16.

Therefore, the video signal according to the high-definition system has an information amount about 5 times that of the video signal according to the NTSC system, and the video signal according to the high-definition system cannot be transmitted as it is by a broadcasting satellite, a video disc or the like.

Therefore, the video signal of the high-definition system is transmitted after being compressed by the so-called MUSE system (multiplex sub-Nyquist sampling system) so that the base band width becomes about 8 MHz. This MUSE method is basically dot interlaced transmission, and the sampling pattern is repeated in a 4-field cycle with offsets between frames, between fields, and between lines.

In the MUSE system, the video signal (luminance signal and color signal) and the quasi-instantaneous companding DPCM are used.
Audio data encoded by the method and an independent additional information signal are multiplexed on the time axis. However, MU
The horizontal frequency and the vertical frequency of the high-definition video signal compressed by the SE method are equal to the horizontal frequency fHM and the vertical frequency fVM of the original high-definition video signal.

In the following description, for simplification, a high-definition video signal data-compressed by the MUSE method is referred to as a "MUSE video signal". A video disc on which an NTSC video signal is recorded is referred to as "NTSC video disc", M
A video disc on which a USE video signal is recorded is called a "MUSE video disc".

Reference: Journal of Television Society, Vol. 42, 8
Issue, etc.

[0009]

This invention is based on the NTSC
The present invention provides a compatible video disc player capable of reproducing both a video disc of a video system and a video disc of a MUSE system, and particularly, it intends to consider the configuration and characteristics of a rotary drive system of the video disc. is there.

[0010]

Therefore, in the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, the first video disc VD in which the video signal SNT of the standard television system is recorded is provided. In the video disc player for reproducing both the video signal SMS of a television system of higher definition than the standard television system and the second video disc VD in which the pilot signal SP of the predetermined frequency fP is recorded, The spindle motor 21, the frequency dividing circuit 63, and the phase comparing circuit 65 which are common to the video disc VD and the second video disc VD.
And a loop filter 67 to which the comparison output V65 of the phase comparison circuit 65 is supplied. Then, when the first video disc VD is reproduced, the synchronization signal included in the video signal SNT reproduced from the first video disc VD.
PBHN and the reference signal REFHN are supplied to the phase comparison circuit 65 for phase comparison, and the output of the loop filter 67 is supplied to the spindle motor 21 to servo-control the first video disk VD to a specified rotation speed. Further, when reproducing the second video disc VD, the second video disc VD is reproduced.
The pilot signal SP reproduced from D is supplied to the frequency dividing circuit 63 to be frequency-divided into a frequency-divided signal S63 close to the frequency of the synchronizing signal PBHN, and the frequency-divided signal S63 and the reference signal REFH2M are phase-compared. It is supplied to the circuit 65 for phase comparison,
The output of the loop filter 67 is supplied to the spindle motor 21 so that the second video disk VD is servo-controlled at a prescribed rotation speed.

[0011]

The phase comparison circuit 65 and the loop filter 67 are common to both the first video disc VD and the second video disc VD.

[0012]

1 and 2 show an example of a video disc player compatible with the NTSC system and the MUSE system according to the present invention, in particular, a rotary drive system thereof. The right side of FIG. 1 is followed by the left side of FIG.

In these figures, VD represents an optical video disc, and this disc VD has N
A TSC video signal SNT or a MUSE video signal SMS is recorded.

In this case, when the disk VD is an NTSC system video disk, the video signal SNT is converted into an FM signal, and the FM video signal, FM audio signal and digital audio signal are frequency-multiplexed. The frequency multiplexed signal SN is recorded. When the disk VD is a MUSE type video disk, the video signal SMS is converted into an FM signal, the FM signal and the pilot signal SP are frequency-multiplexed, and the frequency-multiplexed signal SM is recorded. There is. The frequency fP of the pilot signal SP is fP = 135 fHM / 2 = about 2.28 MHz (1).

Reference numeral 11 denotes an optical head, which reproduces a video signal from the disk VD. When the reproduced signal is the MUSE video signal SM, the original baseband video signal SMS is demodulated when the reproduced signal SM is supplied to the demodulation circuit 12, and the demodulated video signal SMS is converted to the TBC13. Through the MUSE output terminal 14. When the video signal SMS is reproduced, the head 11 also outputs the pilot signal SP at the same time. In addition, a decoder 1 for decoding the video signal SMS into an original high definition video signal is provided at the terminal 14.
Are connected.

The reproduction signal of the optical head 11 is NTC.
In the case of the S type video signal SN, the reproduction signal SN
Are supplied to the demodulation circuit 16 to demodulate the original baseband video signal SNT from the FM signal, and the demodulated video signal SNT is taken out to the NTSC output terminal 18 through the TBC 17. At this time, although the FM audio signal and the digital audio signal are simultaneously output from the head 11, these audio signals are supplied to the audio reproducing circuit 19 and the original audio signals are taken out.

Further, 21 indicates a spindle motor,
In a steady state, the disk VD is rotated by the motor 21 at a predetermined speed, and a frequency generator 22 is provided directly connected to the motor 21, for example, and an alternating signal S22 of 24 cycles is taken out per one rotation of the disk VD.

The optical head 11 is supported by the sled feed mechanism 23 to control the position of the disk VD in the radial direction, and a potentiometer (not shown) provided in the feed mechanism 23 moves the optical head 11 in the radial direction of the head 11. A DC voltage V23 having a value proportional to the position at is taken out.

Further, reference numeral 31 denotes an FG servo circuit, which is for keeping the rotation speed of the disk VD within a range of, for example, ± 20% of a specified value (normal value) during reproduction of the disk VD. The control signal S31 of the switch circuit 32 is also extracted from the servo circuit 31. For this reason,
The servo circuit 31 is configured, for example, as shown in FIG.

That is, the output signal S of the frequency generator 22
22 is supplied to the frequency discrimination circuit (frequency / voltage conversion circuit) 311 and the DC voltage V having a value proportional to the frequency of the signal S22.
22 and this voltage V22 is the voltage comparison circuit 312-314.
Is supplied to. When the disk VD is a CLV disk, the position voltage V23 of the head 11 from the sled feed mechanism 23 is supplied to the voltage dividing circuit 315, and the reference voltages VR + and V +.
R and VR- (VR +>VR> VR-) are formed, and these voltages are supplied to the comparison circuits 312 to 314, respectively.

In this case, the value of the voltage VR is the disk VD
Corresponds to the value of the voltage V22 when the rotation speed of the disk is the specified value, and the value of the voltage VR + corresponds to the value of the voltage V22 when the rotation speed of the disk VD is + 20% faster than the specified value.
Value is -20% of the rotation speed of the disk VD than the specified value.
Corresponds to the value of the voltage V22 at the slowest time.

The comparison output of the comparison circuit 313 is output as the error voltage V31.

The comparison output of the comparison circuit 313 is supplied to the T input of the T flip-flop circuit 318, and the comparison outputs of the comparison circuits 312 and 314 are supplied to the NOR circuit 3.
It is supplied to the reset input! R of the flip-flop circuit 318 through 17 (! Indicates negative).

Then, the Q of the flip-flop circuit 318
The output is supplied to the switch circuit 32 as its control signal S31, and the switch circuit 32 is connected to the state shown in the drawing when the rotation speed of the disk VD is not within the range of ± 20% of the specified value, and ± 20%. When it is within the range of, the connection is made in the opposite state to that shown in the figure.

Although not shown, the disk VD is C
In the case of an AV disc, instead of the position voltage V23, a constant reference voltage corresponding to the reference rotation speed is applied to the voltage dividing circuit 315.
And the voltage V31 and the signal S31 are output. Furthermore, when the disc VD is a MUSE type disc,
The frequency discriminating characteristic of the frequency discriminating circuit 311 is changed to the optimum characteristic when the disc is of the NTSC system.

Reference numeral 40 is a PLL, and 47 and 48 are bandpass filters. These are disc VD MUS
Although it is used in the case of the E type disc, the reproduction signal SM from the head 11 is transmitted by the band pass filter 4
7 and 48 are sequentially supplied. In this case, the pass bands of these filters 47 and 48 are, for example, the filter 4
7 is fP ± 500 kHz (= fP ± 20%), and the filter 48 is fP ± 20 kHz.

Therefore, when the disk VD is rotating within the range of ± 20% of the normal rotation speed, the pilot signal SP can be obtained from the filter 47, and the disk VD can be rotated at the normal rotation speed (or sufficiently high). The pilot signal SP can also be obtained from the filter 48 when rotating at a close rotation speed.

Then, the filter 48 is provided by the PLL 40.
An alternating signal is formed in synchronism with the pilot signal SP from. That is, an oscillation signal S43 whose frequency is, for example, 12 times the frequency fP of the pilot signal SP is extracted from the VCO 43, and this signal S43 is supplied to the frequency dividing circuit 44 and divided into a frequency of 1/12, that is, the frequency fP. The frequency divided signal S44 is supplied to the phase comparison circuit 41, and the pilot signal SP from the filter 48 is supplied to the comparison circuit 41. Then, the comparison output of the comparison circuit 41 is supplied to the VCO 43 as its control voltage through the low pass filter 42 for the loop filter.

Therefore, from the filter 48 to the PLL 40
When the pilot signal SP is supplied to the VCO 43, an oscillation signal S43 having a frequency 12 times that of the pilot signal SP and having a synchronized phase is extracted from the VCO 43, and the frequency divider circuit 44 outputs a frequency equal to the pilot signal SP. Then, the alternating signal S44 having a synchronized phase is extracted.

At this time, part of the comparison output of the comparison circuit 41 is supplied to the lock detection circuit 45, and the PLL 40
A detection signal S45 is taken out which indicates whether or not is locked to the pilot signal SP.

Further, 51 is a system controller composed of a microcomputer, 52 is a frame phase control circuit composed of a gate array, and 53 is a torque control circuit. In this case, the frame phase control circuit 5
2 and the torque control circuit 53, the disk VD is MUSE
This is for speeding up the response when the stop mode, pause mode, search mode, or scan mode is changed to the reproduction mode in the case of the disc VD of the system.

Further, 55 and 56 are sync separation circuits, 57 is a reference signal forming circuit which forms signals of various kinds of timings to be a reference, and 63 is 1/13 the frequency of the pilot signal SP.
5 is a frequency dividing circuit, 65 is a phase comparison circuit, and 66 is a low pass filter for a loop filter. Then, these circuits are for realizing servo control with higher accuracy than the servo circuit 31 for the motor 21 when the rotation speed of the spindle motor 21 is within ± 20% of the specified value.

That is, as will be described in detail later, the disk V
When D is the MUSE system and the rotation speed of the spindle motor 21 is within ± 20% of the specified value, servo control is executed by the frequency dividing circuit 63, the comparing circuit 65, the pilot signal SP, and the frequency dividing signal S44. In addition, the disk VD is N
In the TSC method, when the rotation speed of the spindle motor 21 is within ± 20% of the specified value, the servo control is executed by the comparison circuit 65 and the horizontal synchronizing signal.

Further, reference numeral 68 denotes a lock detection circuit, which detects when the servo locks from the phase difference between the reference signal supplied to the phase comparison circuit 65 and the comparison signal. is there. Also, the switch circuits 64 and 66 are controlled by the system controller 51, and the switch circuits 64 and 66 are connected in the state shown in the figure when the disk VD is a MUSE type disk, and in the state opposite to the figure when the disk VD is an NTSC type disk. .

When the MUSE type disc VD is set in the player, the FG servo (servo control by the servo circuit 31) and the pilot servo (servo control using the pilot signal SP) are sequentially executed so that the disc VD is in a predetermined rotation state. The desired MUSE video signal SMS is reproduced.

When an NTSC disc VD is set in the player, the FG servo H servo (servo control using the horizontal synchronizing signal) is sequentially executed to bring the disc VD into a predetermined rotation state, and the target NTSC system is obtained. Is reproduced. Then, these servo controls 1 to 3 are executed as follows.

When the MUSE type disc VD is set in the FG servo player, various detections are performed by the syscon 51, and the focus servo circuit and the tracking servo circuit (both not shown) are activated. Further, the rotation permission signal SPDL from the system controller 51 is set to “H”, this signal SPDL is supplied to the drive circuit 34, and a predetermined drive voltage is supplied from the drive circuit 34 to the spindle motor 21. Thus, the disk VD starts rotating.

When the disk VD starts to rotate, its rotation speed is not yet within the range of ± 20% of the specified value, and the switch circuit 32 is connected in the state shown in the figure. Therefore, the servo circuit 31 Error voltage V31 output from
Are supplied to the drive circuit 34 through the lines of the switch circuit 32 and the adder circuit 33.

Therefore, the rotational speed of the disk VD is gradually increased by the FG servo circuit 31 and approaches the specified value.

Pilot Servo This pilot servo is executed when the disk VD is a MUSE type disk, but is executed first using the pilot signal SP and then using the divided signal S44.

That is, when the rotational speed of the disk VD falls within the range of ± 20% of the specified value, the FG servo circuit 31
The switch circuit 32 is switched to a state opposite to that shown in the figure by the control signal S31 from the. Therefore, first, the FG servo by the servo circuit 31 is turned off.

Further, in this state, since the PLL 40 is not locked yet, the lock detection signal S45 is "L", and this signal S45 is supplied to the switch circuit 61 through the AND circuit 62 as its control signal, and the switch circuit 61 is controlled. 6
1 is connected in a state opposite to that shown in the figure.

At this time, since the rotation speed of the disk VD is within the range of ± 20% of the specified value, the pilot signal SP is output from the filter 47, but the pilot signal SP from this filter 47 is It is supplied to the frequency dividing circuit 63 through the switch circuit 61 and frequency-divided into a signal S63 having a frequency of 1/135. At this time, if the rotation speed of the disk VD is a specified value, the pilot signal SP
The frequency fP of the divided signal S63 is f63 = fP / 135 = fHM / 2 = 16.875 kHz (2)

Further, since the disk VD is a MUSE type disk and the switch circuits 64 and 66 are connected in the state shown in the figure, the divided signal S63 is supplied to the phase comparison circuit 65 through the switch circuit 64. Further, in the forming circuit 57, the signal RE of the reference phase with the frequency fHM / 2 is used.
FH2M is formed, and this signal REFH2M is supplied to the comparison circuit 65 through the switch circuit 66 as a reference signal.

Thus, in the comparison circuit 65, the divided signal S63 obtained by dividing the pilot signal SP and the reference signal
The phase is compared with that of REFH2M, and the comparison output voltage V65 is supplied to the drive circuit 34 through the line of the low pass filter 67 → in this case, the switch circuit 32 → the adder circuit 33 connected in the state opposite to that in the figure. .

Therefore, in this case, the FG servo by the servo circuit 31 is turned off, and at the same time, the servo using the pilot signal SP, that is, the pilot servo is applied.
The rotation speed of the disk VD further approaches the specified value, and eventually reaches the specified value.

Then, when the rotation speed of the disk VD reaches a specified value, the pilot servo locks at this time, but this is detected by the spindle lock detection circuit 68, and its detection output S68 = "H". Further, at this time, the pilot signal SP is obtained from the filter 48, and the PLL 40 is locked to this pilot signal SP, so that S45 = "H".

When S68 = "H" and S45 = "H", the output of the AND circuit 62 becomes "H", so that the switch circuit 61 is connected in the state opposite to that shown in FIG.
The frequency-divided signal S44 from is supplied to subsequent circuits through the switch circuit 61.

Therefore, thereafter, the pilot servo is continued by the frequency-divided signal S44 synchronized with the pilot signal SP, and the rotation speed of the disk VD is servo-controlled to a specified value.

At this time, the signal S from the PLL 40
43 is supplied to the TBC 13 as a clock for writing, and the forming circuit 57 forms a clock having a reference phase with the same frequency as the signal S43, and this clock is supplied to the TBC 13 as its reading clock. . Thus, the TBC 13 corrects the time axis of the reproduced MUSE video signal SMS.

Further, since it is not the gist of the present invention, only a brief description will be given, but the video signal SMS from the demodulation circuit 12 is supplied to the sync separation circuit 55 to extract the frame sync signal PBFM, and this sync signal PBFM is extracted. Is supplied to the phase control circuit 52, a frame synchronization signal REFFM having a reference phase is formed in the forming circuit 57, and the synchronization signal REFFM is supplied to the control circuit 52.

Then, in the control circuit 52, the phase of the reproduction synchronizing signal PBFM with respect to the reference synchronizing signal REFFM is detected, and the acceleration signal ACCEL or the deceleration signal BRK is formed according to the phase, and these signals ACCEL, BRK are formed.
Is supplied to the torque control circuit 53 to form a drive voltage V53 for acceleration or deceleration, and this voltage V53 is supplied to the addition circuit 33.

Thus, the voltage V53 causes the frame sync signal PBFM of the reproduced video signal SMS to be within a predetermined phase range with respect to the reference frame sync signal REFFM, that is, within the range of the TBC 13. like,
The rotation phase of the disk VD is controlled. The circuit 54
Is a current detection circuit for assisting the operation of the control circuit 53.

H Servo This H servo is executed subsequent to the FG servo of when the disk VD is an NTSC disk.

That is, when the rotation speed of the disk VD falls within ± 20% of the specified value, the FG servo circuit 31
The switch circuit 32 is switched to a state opposite to that shown in the figure by the control signal S31 from the. Therefore, first, the FG servo by the servo circuit 31 is turned off.

The disk VD is an NTSC disk, and the switch circuits 64 and 66 are connected in a state opposite to that shown in the drawing.

Then, the video signal S from the demodulation circuit 16
NT is supplied to the sync separation circuit 56 and the horizontal sync signal PBHN
Is taken out, and this synchronizing signal PBHN is sent to the switch circuit 64.
Is supplied to the phase comparison circuit 65 through the formation circuit 57 and the reference phase signal RE at the horizontal frequency fHN
FHN is formed, and this signal REFHN is supplied to the comparison circuit 65 through the switch circuit 66.

In this way, in the comparison circuit 65, the horizontal synchronizing signal PBHN divided from the video signal SNT and the reference signal
The phase is compared with that of REFHN, and the comparison output voltage V65 is supplied to the subsequent circuits through the low pass filter 67.

Therefore, in this case, the FG servo by the servo circuit 31 is turned off, and at the same time, the horizontal synchronizing signal PB
Since the servo using HN, that is, the H servo is applied, the rotation speed of the disk VD further approaches the specified value by the H servo, and eventually reaches the specified value.

Then, thereafter, the rotation speed of the disk VD is servo-controlled to a specified value by this H-servo. In addition,
During this H servo, the operations of the control circuits 52 and 53 are prohibited.

At this time, the horizontal sync signal PBHN from the sync separation circuit 56 is supplied to the PLL 58 to form a signal of a predetermined frequency in synchronization with the signal PBHN, and this signal is T
The clock is supplied to the BC 17 as a clock for writing, and in the forming circuit 57, a clock having a phase serving as a reference of a predetermined frequency is formed.
7 is supplied as a clock for the reading. Thus, the TBC 17 corrects the reproduced NTSC video signal SNT on the time axis.

Summary In this way, according to the above player, the MUSE type video disc VD and the NTSC type video disc V are used.
It is compatible with D and can be played back on either type of video disc VD.

Moreover, in this case, when the pilot servo is performed on the MUSE type disk VD, the frequency f63 of the divided signal S63 supplied to the phase comparison circuit 65 is
As shown in equation (2), it is 16.875 kHz. Also, NT
When performing H-servo on the disk VD of SC system,
The frequency fHN of the horizontal synchronizing signal PBHN supplied to the phase comparison circuit 65 is about 15.734 kHz.

Therefore, the frequency f63 of the divided signal S63 during pilot servo and the re-horizontal synchronization signal PB during H servo
Since the frequency fHN of HN is almost equal, as described above, the low-pass filter 67 can be used for both the pilot servo and the H servo, and it is not necessary to switch its characteristics. Therefore, it is possible to simplify the configuration of the servo loop of the pilot servo and the H servo, particularly the low-pass filter 67 that is a loop filter.

Furthermore, during reproduction of the MUSE disc VD, the pilot signal SP is easily affected by dropout and the waveform may be lacked. Therefore, the pilot signal SP from the filter 47 is always supplied to the frequency dividing circuit 63. Then, when the pilot servo is performed, the frequency dividing operation of the frequency dividing circuit 63 is disturbed due to the dropout of the pilot signal SP, and the frequency dividing signal S63 contains 1 of the pilot signal SP.
A phase error of about 4.4 μsec (= 1 / fP) is generated per cycle, and thereafter, the phase error is accumulated.

However, in the above-mentioned pilot servo, when the pilot servo is locked, since it is switched to the frequency-divided signal S44 synchronized with the pilot signal SP from the PLL 40 and the pilot servo is continued, the pilot signal SP is dropped out. Even if there is such a situation, a phase error does not occur in the divided signal S63 and the pilot servo is not adversely affected.

Moreover, the PLL 40 used at this time is
Originally, it is for forming the write clock of the TBC 13, and therefore the cost does not increase. That is, it is possible to realize a pilot servo that is resistant to dropout without increasing costs.

[Other Embodiments] By the way, in the above description,
When the FG servo is switched to the pilot servo during reproduction of the MUSE disc VD, the phase comparison circuit 6
If the phase difference between the frequency-divided signal S63 and the reference signal REFH2M supplied to 5 is large, it takes time to pull in the pilot servo.

Such a point is taken into consideration in the example shown in FIG. That is, the frequency dividing circuit 63 is composed of an 8-bit (256-ary) presettable up counter, the value "121" is supplied as the preset data, and the pilot from the switch circuit 61 is used as the count input (clock input). The signal SP (or the divided signal S44) is supplied. Further, the carry output CY of the counter 63 is transferred to the counter 63 via the OR circuit 573.
Is supplied to the load input LD of.

Therefore, the count value of the counter 63 is incremented by "1" for each cycle of the pilot signal SP, and the count value is repeatedly changed in the range of "121" to "255". Therefore, the counter 63 outputs the divided signal S63 obtained by dividing the pilot signal SP by 1/135.

Further, at this time, for example, as shown in FIG. 5A, the control signal S31 which is "H" during the FG servo period and "L" during the pilot servo period is taken out from the FG servo circuit 31. The signal S31 is the AND circuit 57.
2 is supplied. Further, the reference signal RE from the forming circuit 57
FH2M is supplied to the waveform shaping circuit 571, and as shown in FIGS. 5B and 5C, a pulse P57 is generated at each rising edge of the signal REFH2M.
The pulse P571 is shaped into 1 and is supplied to the AND circuit 572.

In this way, the AND circuit 572 causes the circuit shown in FIG.
As shown in D, a pulse P572 is taken out at each rising edge of the reference signal REFH2M during the FG servo period, and this pulse P572 is supplied to the load input LD of the counter 63 through the OR circuit 573.

Therefore, during the FG servo period, as shown in FIG.
As shown in E, the count value of the counter 63 is set to the initial value "121" for each pulse P572, that is, for each rising edge of the reference signal REFH2M, and then for each cycle of the pilot signal SP, "1". It will be incremented.

Then, during the pilot servo period, the pulse P572 is no longer supplied to the counter 63,
As described above, the carry output CY of the counter 63 causes the count value of the counter 63 to be set to the initial value “121”. In this case, during the FG servo period, the count value of the counter 63 becomes the reference value. While changing with the signal REFH2M as the reference, the servo reference of the pilot signal SP during the pilot servo period is the reference signal REFH2M.
Therefore, the pilot servo locks smoothly in a short time at the time of switching between the FG servo and the pilot servo.

Therefore, for example, when the reproduction of the MUSE type disc VD is started, the image output time can be shortened.

In the above description, the discrimination between the MUSE type disc VD and the NTSC type disc VD is as follows.
This can be performed by the difference between the reproduced video signals SMS and SNT or by using the information signal recorded in advance on the disc VD. Also, CLV disc and CA
The same is true for identification with a V disk.

Further, in FIG. 4, for example, when the count value of the counter 63 becomes "134", this is detected by the decoder and the counter 63 is reset to "0" so that the count value of the counter 63 becomes "0". 0 "~" 13
The counter 63 can be reset to "0" by the pulse P572 during the period of FG servo while repeating "4".

[0078]

[Effects of the Invention] MUSE type video disk and NT
It is compatible with SC type video discs and can play back any type of video disc. Moreover, the loop filter for the servo can be used for both the pilot servo and the H servo, and it is not necessary to switch the characteristics, and the configuration can be simplified.

Furthermore, when the pilot servo is locked during playback of the MUSE disc VD, the divided signal from the PLL is used to perform the pilot servo, so that even if there is a dropout in the pilot signal, It does not adversely affect the pilot servo.

Moreover, the PLL used at this time is originally for forming the write clock of the TBC, and therefore, it is possible to realize a pilot servo that is resistant to dropout without increasing the cost.

Further, when the FG servo and the pilot servo are switched, the pilot servo is smoothly locked in a short time. Therefore, for example, when the reproduction of the MUSE disc VD is started, the image output time is shortened. be able to.

[Brief description of drawings]

FIG. 1 is a system diagram showing a part of an example of the present invention.

FIG. 2 is a system diagram showing a continuation of FIG.

FIG. 3 is a system diagram showing an example of a part of the present invention.

FIG. 4 is a system diagram showing an example of another part of the present invention.

5 is a waveform diagram for explaining the operation of the circuit of FIG.

[Description of Codes] 11 Optical Head 12 Demodulation Circuit 13 TBC 16 Demodulation Circuit 17 TBC 21 Spindle Motor 22 Frequency Generator 31 FG Servo Circuit 34 Drive Circuit 40 PLL 45 Lock Detection Circuit 47 Wideband Bandpass Filter 48 Narrowband Bandpass Filter 51 System controller 52 Frame phase control circuit 53 Torque control circuit 54 Current detection circuit 55 Sync separation circuit 56 Sync separation circuit 57 Reference signal forming circuit 58 PLL 63 Frequency divider circuit 65 Phase comparison circuit 67 Low pass filter 68 Lock detection circuit VD video disk

Claims (5)

[Claims] 1. A first video disc on which a video signal of a standard television system is recorded, and a video signal of a television system of higher quality than the standard television system and a pilot signal of a predetermined frequency are recorded. A video disc player for reproducing both a second video disc and a spindle motor common to the first video disc and the second video disc, a frequency dividing circuit, a phase comparison circuit, and A loop filter to which the comparison output of the comparison circuit is supplied, and at the time of reproduction of the first video disc, a synchronization signal included in the video signal reproduced from the first video disc and a reference signal. The output of the loop filter is supplied to the spindle motor to be supplied to the phase comparison circuit for phase comparison. Servo control of the video disc of the second video disc to a specified rotation speed, and at the time of reproducing the second video disc, the pilot signal reproduced from the second video disc is supplied to the frequency dividing circuit to generate the frequency of the synchronizing signal. The frequency-divided signal having a frequency close to, and the frequency-divided signal and the reference signal are supplied to the phase comparison circuit for phase comparison, and the output of the loop filter is supplied to the spindle motor to generate the first signal. A video disc player in which the second video disc is servo-controlled at a specified rotation speed. 2. A first video disc on which a video signal of a standard television system is recorded, and a video signal of a television system of higher quality than the standard television system and a pilot signal of a predetermined frequency are recorded. A video disc player for reproducing both a second video disc and a spindle motor common to the first video disc and the second video disc, a PLL, a frequency dividing circuit, and a phase comparison circuit. A loop filter supplied with a comparison output of the phase comparison circuit, and at the time of reproducing the first video disc, a synchronization signal included in the video signal reproduced from the first video disc and a reference The signal is supplied to the phase comparison circuit for phase comparison, and the output of the loop filter is supplied to the spindle motor. Servo-controls the first video disc to a specified rotation speed, and supplies the pilot signal reproduced from the second video disc to the PLL when reproducing the second video disc. An alternating signal is formed in synchronization with the frequency division circuit, and the alternating signal is supplied to the frequency dividing circuit to divide the frequency dividing signal into a frequency dividing signal having a frequency close to the frequency of the synchronizing signal. A video disc player for supplying a phase comparison circuit for phase comparison, and supplying the output of the loop filter to the spindle motor to servo-control the second video disc to a specified rotation speed. 3. A first video disc on which a video signal of a standard television system is recorded, and a video signal of a television system of higher quality than the standard television system and a pilot signal of a predetermined frequency are recorded. A video disc player for reproducing both a second video disc, a spindle motor common to the first video disc and the second video disc, the first video disc and the second video. It has a detection means for detecting the rotation speed of the disc, a frequency dividing circuit, a phase comparison circuit, and a loop filter to which the comparison output of the phase comparison circuit is supplied, and when reproducing the first video disc, This first
When the rotation speed of the first video disk is not within the predetermined range, the rotation speed of the first video disk is servo-controlled on the basis of the detection output of the detection means to set the rotation speed of the first video disk to the predetermined speed. When the rotation speed of the first video disc is within the predetermined range, the synchronization signal and the reference signal included in the video signal reproduced from the first video disc are phased with each other. It is supplied to a comparison circuit for phase comparison, and the output of the loop filter is supplied to the spindle motor to servo-control the first video disk to a specified rotation speed, and when reproducing the second video disk, This second
When the rotation speed of the second video disk is not within the predetermined range, the rotation speed of the second video disk is servo-controlled based on the detection output of the detection means to set the rotation speed of the second video disk to the predetermined speed. When the rotation speed of the second video disc is within the predetermined range, the pilot signal reproduced from the second video disc or an alternating signal synchronized with the pilot signal is divided by the frequency. The divided signal is supplied to the circuit to be divided into a divided signal having a frequency close to the frequency of the synchronizing signal, and the divided signal and the reference signal are supplied to the phase comparison circuit for phase comparison, and the output of the loop filter Is supplied to the spindle motor to servo control the second video disk to a specified rotation speed. 4. A video disc player for reproducing a video disc on which a video signal of a television system of a higher quality than a standard television system and a pilot signal of a predetermined frequency are recorded, and a spindle motor for rotationally driving the video disc. A PLL to which the pilot signal reproduced from the video disc is supplied, a frequency dividing circuit, a phase comparing circuit for phase comparing the frequency dividing output of the frequency dividing circuit and a reference signal, and the phase comparing circuit. When the video disc is played back, the pilot signal played back from the video disc is fed to the frequency dividing circuit to output a signal having a frequency close to the frequency of the synchronizing signal. The frequency is divided into frequency signals and the output of the loop filter is supplied to the spindle motor. Servo controlling the rotation of the video disc, when the PLL is locked to the pilot signal the reproduction, video disc player the pilot signal supplied to the frequency dividing circuit, and to switch the output signal of the PLL. 5. A video disc player for reproducing a video disc on which a video signal of a television system of higher quality than a standard television system and a pilot signal of a predetermined frequency are recorded, and a spindle motor for rotationally driving the video disc. A detecting means for detecting the rotation speed of the video disc, a frequency divider circuit to which the pilot signal reproduced from the video disc or an alternating signal synchronized with the pilot signal is supplied, and a frequency divider of the frequency divider circuit. It has a phase comparison circuit for comparing the output and the reference signal in phase, and a loop filter to which the comparison output of this phase comparison circuit is supplied. When it is not within the range, the video data is detected based on the detection output of the detection means. The rotation speed of the disc is servo-controlled so that it falls within the predetermined range, and the frequency dividing circuit is set to an initial value in synchronization with the reference signal so that the rotation speed of the video disk is within the predetermined range. In the case of, the pilot signal reproduced from the video disc or an alternating signal synchronized with the pilot signal is supplied to the frequency dividing circuit to divide the frequency into a frequency dividing signal having a frequency close to the frequency of the synchronizing signal. A video disc player in which the output of a loop filter is supplied to the spindle motor to servo-control the video disc to a specified rotation speed.