JPH0711896B2 - Optical disc player - Google Patents

Description

The present invention relates to an optical disk reproducing device, and more particularly to an LD and a CD.
The present invention relates to an optical disc reproducing device capable of reproducing both a video area in which at least an FM modulated video signal is recorded in V and the like and an audio area in which only digital audio signals are recorded in CD, CDV and the like.

[Conventional technology]

For example, when playing a video area of a CDV disc with a player capable of playing a CDV, the disc motor rotation control is performed by
The disk motor rotation control system shown in the figure is used.

When the disk 10 is in the steady reproduction rotation state, rotation control is performed based on the horizontal synchronizing signal in the reproduced video signal.

That is, the photodetection signal of the optical pickup 12 is amplified by the amplifier 14, and after the RF signal is detected, the bandpass filter 16 performs FM detection.
The modulated video signal is taken out.

Next, the modulator 18 demodulates the composite video signal, and the horizontal sync detection circuit 20 detects the horizontal sync signal from the composite video signal.

The horizontal synchronizing signal is phase-compared with the reference signal from the reference signal generator 24 by the phase comparator 22, and the phase difference pulse (error signal) is integrated by the LPF 26 and then passed through the changeover switch 28 which is switched to the L side and the amplifier. The signal is amplified at 30, output to the disk motor 32, and driven.

As a result, the disk 10 rotates so that the frequency of the horizontal synchronizing signal in the composite video signal exactly matches the specified value, and image reproduction becomes possible.

At this time, a digital audio signal component is extracted from the RF signal by the LPF 34, waveform-shaped by the waveform shaping circuit 36, and then input to the CD signal processing circuit 38 to read the audio sample data.

On the other hand, if the disk has not reached a sufficient rotation speed immediately after it has risen from the stopped state, or if it has run out of control and an abnormally high rotation speed has occurred, the horizontal sync signal will be exceeded due to the frequency limit of the demodulator 18 etc. Cannot be detected normally, and the above rotation control does not work properly.

Therefore, during non-steady-state reproduction in which the rotation speed of the disk 10 deviates significantly from the value during steady-state reproduction, the rotation speed of the disk motor 32 itself is directly detected, and rotation control is performed so that this becomes a predetermined value.

For example, the FG of the frequency generator 40 attached to the disk motor 32
The signal is amplified by the amplifier 42, and further the frequency / voltage conversion circuit
After the voltage is converted into a voltage corresponding to the motor rotation speed in 44, it is compared with the reference voltage in the comparison circuit 46, and the error signal is switched to the U side before the disk motor 32 is started or when the runaway is detected. The output is provided to the amplifier 30 via the changeover switch 28.

As a result, when the disk motor 32 is activated, it is controlled so as to rise with a predetermined rotation speed as a target, and at the time of runaway, control is performed so as to return to the predetermined rotation speed.

When the horizontal rotation signal is detected at the specified rotation speed,
By switching the changeover switch 28 to the L side, it is possible to shift to the accurate disc rotation control described above.

[Problems to be Solved by the Invention] However, in such a conventional technique, in order to perform the disc motor rotation control during unsteady reproduction in the video area,
It is necessary to install a frequency generator and a motor back electromotive force detector for detecting the number of revolutions in the disk motor, and to provide a frequency / voltage conversion circuit, etc., which complicates the configuration, increases the cost of parts, and reduces the device size. There was a problem that it was difficult to realize.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an optical disk reproducing apparatus which has a simple structure, reduces the cost of parts, and is easily miniaturized.

[Means for Solving the Problems]

The present invention is an optical disc reproducing apparatus capable of reproducing an audio area in which only a digital audio signal is recorded and a video area in which at least an FM-modulated video signal is recorded, and a synchronization separated from the FM-modulated video signal during steady reproduction in the video area. First rotation control means for controlling the disk rotation so that the signal cycle matches the cycle of the reference signal, and the clock component extracted from the playback EFM signal of the audio area input during steady playback in the audio area. The second rotation control means for controlling the disc rotation so that the period of the same as the period of the reference signal and the reproduction EFM signal of the audio area during the non-steady reproduction in the audio area are input, and the length of the predetermined pulse in this is input. The third rotation control means for controlling the disc rotation so that the distance becomes equal to the reference length, and the reproduction pit signal of the video area are given a predetermined frequency division ratio. The frequency dividing means is provided with frequency dividing means for making the length of the predetermined pulse during the frequency division output substantially equal to the length of the predetermined pulse of the reproduced EFM signal in the audio area. Is input to the third rotation control means, and the disk rotation control is performed by the third rotation control means so that the length of the predetermined pulse in the output of the frequency dividing means matches the reference length. It is characterized by having done.

[Action]

According to the present invention, during steady reproduction in the video area, disk rotation control is performed so that the cycle of the sync signal separated from the FM-modulated video signal by the first rotation control means matches the cycle of the reference signal, and the audio area is reproduced. During steady playback in, the second rotation control means performs disc rotation control so that the cycle of the clock component extracted from the reproduced EFM signal in the audio area matches the cycle of the reference signal, and during non-steady playback in the audio area. The third rotation control means controls the rotation of the disk so that the length of the predetermined pulse in the reproduced EFM signal in the audio area matches the reference length.

Also, during unsteady playback in the video area, the playback pit signal in the video area is divided by the frequency dividing means, and the length of the predetermined pulse during frequency division output is equal to the length of the predetermined pulse in the playback EFM signal in the audio area. After making them substantially equal, they are input to the third rotation control means, and the disk rotation control is performed by the third rotation control means so that the length of the predetermined pulse of the frequency division output matches the reference length.

As a result, even if the disk motor itself is not provided with a rotation speed detector, a frequency / voltage converter, etc., it is possible to add a relatively simple circuit to the audio area for steady reproduction and non-steady reproduction, and for the video area. The disk rotation control can be performed during both the steady reproduction and the non-steady reproduction, and the cost can be reduced and the device can be downsized. In particular,
Even if all or part of the video area does not include a pulse signal that can be used for disk rotation control other than the FM-modulated video signal, the third rotation control means ensures that the disk is rotated by the third rotation control means during unsteady reproduction of the video area. Rotation control can be performed.

〔Example〕

 An embodiment of the present invention will be described with reference to FIG.

Configuration of Embodiment FIG. 1 is a block diagram of a disc motor rotation control system of an optical disc reproducing apparatus according to the present invention.

The disk 10 is set on a table connected to the rotary shaft of the disk motor 32 and is rotationally driven.

The signal recorded on the disk 10 is detected by the optical pickup 12 and output as a light detection signal.

An amplifier 14 is connected to the output side of the optical pickup 12 to amplify a photo detection signal and output an RF signal.

The output side of the amplifier 14 is divided into a plurality of systems, one of which is connected to the band pass filter 16 of the video system.
The FM modulated video signal is taken out.

A demodulator 18 is connected to the output side of the bandpass filter 16 and demodulates a composite video signal from the FM modulated video signal.

A horizontal sync detection circuit 20 is connected to the output side of the demodulator 18 to separate the horizontal sync signal from the composite video signal.

A phase comparator 22 is connected to the output side of the horizontal sync detection circuit 20, and a reference signal (1
5.734KHz) and the phase of the horizontal synchronizing signal are compared, and the phase difference pulse (error signal) is output.

The output side of the phase comparator 22 is connected to the LPF 26 to integrate the error signal.

The output side of the LPF 26 is connected to the input terminal L side of the changeover switch 28.

An amplifier 30 is connected to the output terminal S of the changeover switch 28, the switch is changed over to the L side during steady reproduction in the video area, and the LPF 26 amplifies the error signal after integration.
It is output to the disk motor 32.

As a result, disk rotation control during steady reproduction is performed.

The output side of the amplifier 14 is also connected to the audio system.

The output side of the amplifier 14 is directly connected to the input terminal A (audio) side of the changeover switch 48 and also connected to the input terminal V (video) side of the changeover switch 48 via the LPF 34.

The output terminal C of the changeover switch 48 is connected to the waveform shaping circuit 36.

Here, the selector switch 48 is switched to the A side when reproducing the audio area of CD or CDV, and the RF signal is directly input to the waveform shaping circuit 36 to restore the EFM signal (binarized RF signal).

On the contrary, when the LD or CDV video area is reproduced, the changeover switch 48 is switched to the V side, the digital audio signal portion is extracted from the RF signal by the LPF 34, and then the waveform is shaped to restore the EFM signal.

This EFM signal corresponds to the pit signal in the audio area of CD or CDV, but corresponds to the change of the duty ratio of the pit signal in the video area of LD or CDV. However, the recording level of digital audio signals is lower than that of FM-modulated video signals.
It is 27 dB smaller, and the duty ratio change due to the digital audio signal occurs near 50%.

The output side of the waveform shaping circuit 36 is the input terminal P of the changeover switch 50.
The output terminal R of this selector switch 50 is connected to the
Is connected to the CD signal processing circuit 38A.

Servo circuit of the embodiment When the optical pickup 12 is in the audio area and during the steady reproduction in the video area, the changeover switch 50 is switched to the P side, and during the steady reproduction, the CD signal processing circuit 38A reproduces the audio sample data from the EFM signal. Is done.

This audio sample data is output to a D / A converter (not shown) or the like connected to the output side of the CD signal processing circuit 38A.

The CD signal processing circuit 38A also has a function of forming an error signal for controlling the disc motor from the input signal, and the operational amplifier 52 connected to the output side of the error signal.
Is output to and integrated.

The output side of the operational amplifier 52 is connected to the input terminal U side of the changeover switch 28, and the switch is changed over to the U side except during the steady reproduction in the video area, and the disc is output based on the error signal of the CD signal processing circuit 38A. The rotation control of the motor 32 is performed.

Here, a method of forming an error signal by the CD signal processing circuit 38A will be described.

During steady playback of the audio area, the EFM input by switching the A side of the selector switch 48 and the P side of the selector switch 50.
The PLL clock extraction circuit extracts the clock from the signal, compares the phase of this clock with the reference signal (frequency 4.3218MHz), and outputs the phase difference pulse as a normal servo error signal.

The clock frequency of the EFM signal is 4.3218 MHz during accurate reproduction according to the CD format.

Also, during non-steady-state playback (when the PLL clock extraction circuit is unlocked due to rotation start, track jump, etc., or during high-speed search, etc.), the pulse with the maximum pulse width in the input signal (EFM signal is input) The frame sync pulse), and the difference between the pulse width of that pulse and the pulse width of the frame sync pulse (approximately 2.545 μs) during accurate steady playback in the audio area is used as the error signal for rough servo. Output as.

As the CD signal processing circuit 38A having such a function, for example, there is a CX23036 manufactured by Sony, which is a CD LSI, and the CX23036 may be set to the CLV-P, CLV-S, and CLV-H modes.

However, the disk motor rotation control based on the error signal from the CD signal processing circuit 38A is performed with the target that the clock frequency of the reproduced EFM signal becomes 4.3218 MHz when the input signal is the EFM signal related to the digital audio signal. It

The CD signal processing circuit 38A also has a function of detecting a lock / unlock state of the PLL clock extraction circuit and outputting a detection signal, and a function of detecting lock / unlock of the rough servo and outputting a detection signal.

The output of the amplifier 14 is also connected to the rough servo system in the video domain.

That is, the output side of the amplifier 14 is connected to the waveform shaping circuit 54, the pit signal in the video area is restored, and the reproduced pit signal (binarized RF signal) is output.

The output side of the waveform shaping circuit 54 is connected to the frequency divider 56, and divides the frequency at a ratio of 1/40, for example.

The function of the frequency divider 56 will be described. The maximum pulse of the playback EFM signal in the audio area is the frame sync pulse, and the pulse width of the frame sync pulse during steady playback is approximately
It is 2.545 μs. On the other hand, regarding the pulse of the playback pit signal in the video area, the pulse frequency corresponds to the frequency of the FM-modulated video signal, and when the digital audio signal is superimposed, the change in duty ratio corresponds to the digital audio signal. There is. However, the recording level of the digital audio signal is MF
It is -27 dB smaller than the modulated video signal, and the change in duty ratio due to the digital audio signal occurs near 50%.

Therefore, the pulse width of the reproduction pit signal in the video area roughly corresponds to the frequency of the FM-modulated video signal, and the maximum pulse of the reproduction pit signal in the video area corresponds to the FM-modulated video signal at the tip of the sync tip. For example, in the case of the NTSC system, the maximum pulse width during steady reproduction is about 2.63 × 40 μs. Therefore, by dividing the frequency by 1/40 by the frequency divider 56, the maximum pulse length in the frequency-divided output can be made substantially equal to the maximum pulse length of the reproduced EFM signal in the audio area.

The output side of the frequency divider 56 is connected to the input terminal Q side of the changeover switch 50.

The changeover switch 50 is used for non-steady-state playback in the video area (when the PLL clock extraction circuit is unlocked due to rotation start, track jump, etc., or during high-speed search)
Is switched to the Q side, and the output signal of the frequency divider 56 is input to the CD signal processing circuit 38A instead of the EFM signal.

Therefore, the CD signal processing circuit 38A outputs the above-mentioned error signal based on the frequency division output.

Operation of the Embodiment (1) Audio Area Next, the operation of the above embodiment will be described.

First, the optical pickup in the audio area of the CD or CDV 12
When the disk 10 is started from the stopped state, the selector switch 28 is switched to the U side, the selector switch 48 is switched to the A side, the selector switch 50 is switched to the P side, and the CD signal processing circuit 38A is set to the rough servo mode. .

Switch switching and mode setting are performed by a system microcomputer (not shown).

At first, since the RF signal is not detected when the disk 10 is still stopped, the error signal for rough servo output by the CD signal processing circuit 38A is the maximum (indicating that the rotation speed of the disk is slow). After being integrated by the operational amplifier 52, it is sent to the amplifier 30 via the changeover switch 28, where it is amplified and output to the disk motor 32 as a starting voltage.

This causes the disk 10 to start rotating.

The optical pickup 12 starts detecting an optical signal by the rotation of the disk 10, and is amplified by the amplifier 14 and input as an RF signal to the waveform shaping circuit 36 via the changeover switch 48.

The waveform shaping circuit 36 forms an EFM signal from the RF signal and inputs it to the CD signal processing circuit 38A via the changeover switch 50.

The CD signal processing circuit 38A detects the pulse having the maximum pulse width from the input EFM signal and compares it with 2.545 μs (hereinafter referred to as τ).

The maximum pulse width in the EFM signal is the frame sync pulse, but the frequency of the entire EFM signal is low immediately after the start of rotation of the disk 10, and therefore the pulse width is much longer than τ.

Therefore, for a while, an error signal indicating that the rotation of the disk 10 is slow continues to be output.

Since this error signal is integrated by the LPF 52, the output of the LPF 52 increases and the voltage applied to the disk motor 32 increases.

This accelerates the rotation of the disk 10.

When the disc 10 rotates faster, the overall frequency of the reproduced FEM signal rises, and the pulse width of the frame sync pulse becomes τ.
Approaching.

Therefore, the error signal gradually decreases and the disk motor
The increase in voltage applied to 32 also slows down.

Finally, when the frame sync pulse width in the reproduced EFM signal matches τ, the rough servo lock detection signal is output.

When this lock signal is detected, the CD signal processing circuit
Set 38A to regular servo mode.

At this time, the PLL clock extraction circuit has begun to extract the clock for the first time, and after the mode switching, the CD signal processing circuit 38A obtains the error signal from the clock extracted from the EFM signal and the reference signal and outputs it to the operational amplifier 52.

As a result, accurate rotation control of the disc motor 32 is performed.

At this time, audio sample data is reproduced by demodulation and other signal processing for the EFM signal and output to the outside.

When the PLL clock extraction circuit is unlocked due to a track jump or runaway rotation during steady playback of the audio area, the unlock servo signal is activated to set the rough servo mode and after the rough servo locks. It will be returned to the normal servo state.

Also, during the high speed search, the rough servo mode is set by being urged by the predetermined mode switching command.

(2) Video area In contrast to this, when the optical pickup 12 is in the LD or CDV video area and the disk 10 is started from the stopped state, the changeover switch 28 is on the U side, the changeover switch 48 is on the V side, and the changeover switch 50 is on. Switching to Q side and CD signal processing circuit
38A is set to rough servo mode.

At first, since the RF signal is not detected when the disk 10 is still stopped, a large rough servo error signal is output from the CD signal processing circuit 38A, which is integrated by the operational amplifier 52 and then the amplifier 30 via the changeover switch 28. Sent to
Here, it is amplified and output as a moving voltage to the disk motor 32.

This causes the disk 10 to start rotating.

The optical pickup 12 starts detecting an optical signal by the rotation of the disk 10, is amplified by the amplifier 14, and is input to the waveform shaping circuit 54 as an RF signal.

A pit signal is formed from the RF signal by the waveform shaping circuit 54, and the pit signal is input to the frequency divider 56 and divided into 1/40.

Here, the pit signal corresponds to the FM modulated video signal, and when reproduced at a regular rotation speed, the NTSC system has a sync tip tip of 7.6 MHz and a white peak of 9.3 MHz.

The period is about 131.6 ns to 107.5 ns, and the pulse width after dividing by 1/40 is about 2.63 μs to 2.15 μs. The pulse width of the divided output at the tip of the sync tip is about 2.63 μs, which is the maximum pulse of the reproduced EFM signal at the normal rotation speed in the audio area. The pulse width of the frame sync pulse is about 2.54.
It is almost equal to 5 μs. Therefore, rough servo can be performed by inputting the divided output of the reproduction pit signal in the video area to the CD signal processing circuit 38A.

The divided output is sent to the CD signal processing circuit 38A via the selector switch 50.
Is input to.

The CD signal processing circuit 38A detects a pulse having the maximum pulse width from the input divided signal and compares it with τ.

The maximum pulse width in the divided signal is due to the sync tip portion, but immediately after the start of rotation of the disk 10, the frequency of the entire divided signal is low, and thus the pulse width is much longer than τ.

Therefore, for a while, an error signal indicating that the rotation of the disk 10 is slow continues to be output.

Since this error signal is integrated by the operational amplifier 52, the output of the operational amplifier 52 increases and the voltage applied to the disk motor 32 increases.

This accelerates the rotation of the disk 10.

When the disk 10 rotates faster, the overall frequency of the divided signal rises, and the maximum pulse width related to the sync tip portion is τ
Approaching.

Therefore, the error signal gradually decreases and the disk motor
The increase in voltage applied to 32 also slows down.

Finally, when the maximum pulse width in the divided signal matches τ, the rough servo lock detection signal is output.

When this lock signal is detected, the CD signal processing circuit
38A is set to the normal servo mode, and the selector switch 28 is switched to the L side and the selector switch 50 is switched to the P side.

When the maximum pulse width in the frequency-divided signal matches τ, the instantaneous frequency at the sync tip of the reproduced FM-modulated video signal is about 7.85MHz, which is slightly higher than normal but sufficient for the demodulator 18 to operate. Frequency.

Therefore, at this time, the bandpass filter 16 has already been applied to the RF signal.
The MF modulated video signal is extracted, and the demodulator 18 demodulates the composite video signal.

Further, the horizontal sync detection circuit 20 separates the horizontal sync signal from the composite video signal, and the phase comparator 22 compares the phase with the reference signal to output an error signal.

Therefore, after the mode switching, accurate rotation control for the disk motor 32 is performed by the error signal based on the horizontal synchronizing signal.

At this time, a digital audio signal component is extracted from the RF signal by the LPF 34, an EFM signal is further formed by the waveform shaping circuit 36, and the EFM signal is input to the CD signal processing circuit 38A.

Therefore, after the mode switching, the audio sample data is reproduced by the CD signal processing circuit 38A and output to the outside.

When the PLL clock extraction circuit is unlocked due to a track jump, runaway rotation, or the like during steady reproduction in the video area, the unlock servo detection signal is applied to set the rough servo mode.

At this time, the changeover switch 28 is changed over to the U side and the changeover switch 50 is changed over to the Q side.

Then, after the rough servo is locked, it is returned to the normal servo state.

Also, during the high speed search, the rough servo mode is set by being urged by the predetermined mode switching command.

Example Summary According to this example, the pit signal obtained by waveform shaping of the RF signal by the waveform shaping circuit 54 at the time of unsteady reproduction in the video region of the LD or CDV is divided by the frequency divider 56 into a predetermined amount. The frequency is divided by the frequency ratio and input to the CD signal processing circuit 38A, and the CD signal processing circuit 38A forms an error signal for rough servo to control the rotation of the disk motor 32. It is not necessary to provide a generator or a motor back electromotive force detector, and it is not necessary to provide a frequency / voltage conversion circuit, etc., and a relatively simple circuit can be added to perform disk motor rotation control during specific steady playback in the video area. The cost can be reduced and the device can be downsized.

Even when all or part of the video area does not contain a pulse signal that can be used for disc rotation control other than the FM-modulated video signal, the disc rotation control is performed reliably during unsteady playback of the video region. It is possible to reach the speed at which the regular servo is possible.

Although the frequency division ratio of the frequency divider is 1/40 in the above embodiment, this is merely an example, and in the case of the NTSC system, it may be set in the range of 1/35 to 1/45, and In a PAL type optical disc reproducing apparatus, it may be set to about 1/30 to 1/40.

The rough servo is performed by detecting the pulse with the maximum pulse width in the input signal of the CD signal processing circuit 38A, but it may be performed by detecting the pulse with the minimum pulse width.

〔The invention's effect〕

According to the optical disk reproducing apparatus of the present invention, during steady reproduction in the video area, disk rotation control is performed so that the synchronization of the synchronization signal separated from the FM modulated video signal by the first rotation control means matches the synchronization of the reference signal. During steady playback in the audio area, the disk rotation control is performed by the second rotation control means so that the cycle of the clock component extracted from the reproduced EFM signal of the audio area matches the cycle of the reference signal. During non-steady-state reproduction, the third rotation control means controls the disc rotation so that the length of the predetermined pulse in the reproduced EFM signal in the audio area matches the reference length, and during the non-steady-state reproduction in the video area. The frequency of the reproduction pit signal in the video area is divided by the frequency dividing means, and the length of the predetermined pulse during frequency division output is the same as the predetermined pulse length of the reproduction EFM signal in the audio area. After equalizing them, they are input to the third rotation control means, and the disk rotation control is performed by the third rotation control means so that the length of the predetermined pulse in the frequency division output matches the reference length. , Even when the disk motor itself is not equipped with a rotation speed detector, frequency / voltage converter, etc., a relatively simple circuit can be added to the audio region for steady playback, non-steady playback, and video region steady playback. Also, the disk rotation control can be performed in any of the constant steady reproduction, and the cost can be reduced and the device can be downsized. In particular, even when all or part of the video area does not include a pulse signal that can be used for disk rotation control other than the FM-modulated video signal, the third rotation control means can be reliably operated during unsteady reproduction of the video area. Thus, the disc rotation control can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical disc reproducing apparatus according to one embodiment of the present invention, and FIG. 2 is a block diagram of a conventional optical disc reproducing apparatus. 10: disc, 12: optical pickup, 32: disc motor, 38A: CD signal processing circuit, 54: waveform shaping circuit, 56: frequency divider.

Claims (1)

[Claims] 1. An optical disk reproducing apparatus capable of reproducing an audio area in which only a digital audio signal is recorded and a video area in which at least an FM-modulated video signal is recorded, and is separated from an FM-modulated video signal during steady reproduction in the video area. First rotation control means for controlling the disk rotation so that the cycle of the synchronization signal matches the cycle of the reference signal, and the reproduction of the audio area during the steady reproduction in the audio area.
The second rotation control means for controlling the disk rotation so that the cycle of the clock component extracted from this by inputting the EFM signal matches the cycle of the reference signal, and the reproduction of the audio area during the non-steady-state reproduction in the audio area Third rotation control means for inputting the EFM signal and controlling the disk rotation so that the length of a predetermined pulse in the EFM signal coincides with the reference length, and the reproduction pit signal in the video area is divided by a predetermined division ratio. Then
Playback of audio area when the length of the specified pulse during frequency division output
A frequency dividing means for making the length of a predetermined pulse of the EFM signal approximately equal is provided, and during non-steady reproduction in the video area, the output of the frequency dividing means is input to the third rotation control means to output the output of the frequency dividing means. An optical disk reproducing apparatus, characterized in that the disk rotation control is performed by the third rotation control means so that the length of a predetermined pulse therein matches the reference length.