JPH0619896B2 - Disc player - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc player for reproducing information from a disc on which information is recorded while changing angular velocity on a concentric or spiral information track.

2. Description of the Related Art Discs on which information is recorded on concentric or spiral information tracks at a constant linear velocity include digital audio discs on which audio signals are digitally recorded and video discs on which audio signals and composite video signals are recorded. .
In a player that reproduces these discs, so-called spindle servo that controls the rotation speed of the disc is performed in order to reproduce a signal at a constant linear velocity as in recording. By this servo, the rotation is controlled so that the inner circumference of the disk is fast and the outer circumference is slow.

By the way, in this type of player, in addition to the normal reproduction function, a fast-forward operation is usually possible in order to quickly search for a target reproduction device. That is, during normal reproduction, the information read position by the pickup is controlled so that information is sequentially reproduced from one track, whereas when a fast-forward instruction is received from the outside, the information read position is moved by a predetermined number of tracks. The playback position is moved at a high speed by repeating the operation of forcibly moving in the disk radial direction (so-called jump operation), performing playback for a certain period of time, and then performing the jump operation again. At this time, immediately after the jump operation is performed, the disc maintains the rotational speed immediately before the jump, so that an error in the linear velocity occurs due to the difference in the radial position.
This speed error is eliminated by the spindle servo adjusting the disk rotation speed, but normal signal reproduction cannot be performed until then. Especially when performing so-called low-frequency compensation that raises the gain in the low frequency range in order to suppress steady errors in the spindle servo, the speed pull-in operation remains as a residual error and remains unaffected. The period tends to expand further.

In order to solve such a problem, for example, JP-A-62-2
The following method is disclosed in Japanese Patent No. 59262. That is, while the jump operation is being performed, a forced acceleration or deceleration signal is injected into the spindle servo system according to the jump direction to match the disk rotation speed with the rotation speed of the jump destination in advance. The spindle servo pull-in operation is unnecessary.

However, in the above method, the amount of the signal to be forcibly injected in order to eliminate the velocity error after the jump differs depending on the radial read position. there were. Further, since the control is feedforward type, there is a problem that it is not possible to deal with the variation of each element, for example, the variation of the torque constant of the motor, and the speed error cannot be completely eliminated.

Means for Solving the Problems To solve the above problems, the disc player of the present invention reads information from a disc on which information is recorded while changing the angular velocity on a concentric or spiral information track and outputs a reproduction signal. Reading means, trigger generating means for outputting a jump trigger in response to an operation from the outside, and an information reading position when the information reading position by the reading means is controlled on a predetermined track and the jump trigger is input. Position control means for forcibly moving in the disk radial direction by a predetermined number of tracks, sync separation means for separating and outputting the sync signal included in the reproduction signal, and a reference sync signal which is the reference of the sync signal. The reference generating means for outputting and the frequency and / or phase of the synchronizing signal and the reference synchronizing signal are compared and an error signal is outputted. Rotation error detecting means for applying force, integrating means for integrating the error signal, adding means for adding the error signal and the integrated error signal, and drive for rotating the disk based on the output of the adding means. Means and integration prohibition means for stopping the integration operation by the integration means for a predetermined period from the jump trigger and holding the integration output.

Further, instead of the integration prohibiting means, there is provided a time constant switching means for making the integration time constant by the integrating means larger than the normal time for a predetermined period from the jump trigger.

Operation With the above-described configuration, the disc player of the present invention can reduce the disturbance of the spindle servo system after the jump and shorten the pull-in period.

Embodiment A disc player according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a disc player according to an embodiment of the present invention. In FIG. 1, 1 is a disk, 2 is reading means, 3 is trigger generating means, 4 is position controlling means, 5 is synchronous separating means, 6 is reference generating means, 7 is rotational error detecting means, 8 is integrating means, and 9 is. Is an adding means, 10 is a driving means, and 11 is an integration prohibiting means. The reading means 2 reads information from the rotating disc 1 and outputs a reproduction signal. The configuration of the reading means 2 differs depending on the type of the disc 1, but in the case of a compact disc or an optical video disc, for example, it is composed of an optical pickup and a control circuit for focusing. The trigger generating means 3 outputs a jump trigger according to an operation from the outside. FIG. 2 shows an example of input / output waveforms of the trigger generating means 3, and the symbols in FIG. 2 respectively represent the signal waveforms at the points indicated by the same symbols in FIG. The period in which the input a is at the "H" level indicates that fast-forward is instructed by a method such as operating a switch from outside the player. Therefore, the period trigger generating means 3 generates the jump trigger b at constant time intervals. In this case, the rising edge of b represents the trigger timing for causing a jump. Further, as compared with the track eccentricity of the disk and the clamping accuracy of the disk, it is necessary to perform tracking control on a disk having a small track pitch so that the information reading position by the pickup follows the track according to the rotation of the disk. The position control means 4 includes a control circuit for this purpose and, at the same time, inputs a jump trigger to cause the reading means 2 to perform a jump operation. FIG. 3 is a signal waveform diagram showing an example of the operation at that time. In the figure, b is a jump trigger as in FIG. 2, and c is a signal applied to a tracking actuator not shown in FIG. In synchronism with the rising edge of b, the forced acceleration pulse c1 and the forced deceleration pulse c2 are applied to the actuator to perform the jump operation. As a result, the player repeats the operation of performing the jump operation in synchronization with the rising edge of the jump trigger and then performing the reproduction until the next jump trigger is input. In this way, the reproduction signal output from the reading unit 2 while performing the fast-forward operation is guided to the synchronization separating unit 5 and the synchronization signal included in the reproduction signal is extracted. The sync separating means 5 can be composed of an FM demodulation circuit, a clamp circuit, and a comparator when the reproduction signal is, for example, an FM-modulated video signal. When the reproduced signal is a digital signal and the sync signal is recorded as a so-called sync pattern, the sync separation means 5
Is composed of a digital signal processing circuit. The obtained synchronizing signal is input to the rotation error detecting means 7 together with the reference synchronizing signal generated by the reference generating means 6. The rotation error detection means 7 compares the frequency and / or phase of the two input signals and outputs an error signal according to the result. There are various configurations of the rotation error detecting means 7, and details thereof will not be described here. The integrating means 8 and the adding means 9 are inserted for the purpose of increasing the loop gain in the low frequency range and suppressing the stationary residual error, and are generally called low frequency compensation or integral compensation. The integration prohibiting means 11 has the integration means 8 for a predetermined period after the jump trigger is input.
It works to prohibit the integral action of. The output of the adding means 9 is guided to the driving means 10 to drive the disk 1 to rotate. Although a large speed error occurs immediately after the jump operation, conventionally, an excessive error signal generated during the speed pull-in operation is directly integrated by the integrating means 8,
Since it remains even after the end of velocity pull-in, the spider servo system was disturbed as a residual error. According to the above configuration, the integration operation by the integration means 8 is prohibited by the integration prohibition means 11 during a period in which an excessive error signal is generated.
This adverse effect can be avoided, and the normal playback state can be restored faster.

FIG. 4 is a signal waveform diagram showing an example of the state of the error signal when the jump operation is performed. B is a jump trigger, f is a signal representing the integration prohibition period by the integration prohibition means 11, and d is a signal.
Reference numerals 1 and 2 respectively show the phase error states in the conventional disc player and the disc player of the present invention.
Both start the jump at time t1, and the jump operation ends and the speed pull-in operation starts at time t2, but in the case of the present invention, the integral operation is prohibited from time t1 to t3. As a result, it can be seen that the magnitude of the error near time t4 is reduced to about 1/2 in the method of d2 compared to d1.

FIG. 5 shows an example of the circuits of the integrating means 8, the adding means 9, and the integrating prohibiting means 11. In the figure, r1 ...
r8 is a resistor, c1 and c2 are capacitors, 501 is a one-shot monomulti, and r is synchronized with the fall of the input T.
A pulse having a width corresponding to the time constant of 8 and c2 is output from Q. Reference numerals 502 and 503 denote operational amplifiers, and 504 is an analog switch, which is in an “open” state while the control signal 5f is at “H” level. 5b is an input of a jump trigger, which is at "L" level during normal reproduction, so one-shot monomulti 5
01 does not work and the analog switch 504 is'closed '. Therefore, the error signal input from 5d is r1,
The error signal 5 is integrated by the integrating means 8 including r2, r3, c1 and the operational amplifier 502, and added by the adding means 9 including r4, r5, r6, r7 and the operational amplifier 503.
It is added to d and output from 5e. On the other hand, at the time of fast-forwarding, a pulse having a constant time width appears at 5f in synchronization with the rising edge of the jump trigger input from 5b, so that the analog switch 504 is "closed" during that period and the input of the integrating means 8 is prohibited and the output is held. It becomes a state.

FIG. 6 shows the integrating means 8, the adding means 9, and the integrating prohibiting means 11.
Another example of the circuit is shown, which is an example in which the same configuration as that of FIG. 5 is realized by a digital circuit. In the figure, 601 is a one-shot monomulti, 602 is a latch, 603 and 607 are adders, 604 is an AND gate, 605 is a clock generation circuit, and 606 is a multiplier. The integrator 8 is composed of a latch 602 and an adder 603, and executes integration by successively integrating the input 6d each time a clock signal is applied from the clock generation circuit through the AND gate 604. This output is multiplied by a constant in the multiplier 606 to adjust the gain, and then the adder 6
At 07, it is added to the original error signal 6d and output to 6e. On the other hand, since the jump trigger is input from 6b to the one-shot monomulti 601, a pulse of "L" level having a constant time width appears at its output Q. Duration of this pulse
Since the AND gate 604 is closed and the clock signal is not supplied to the latch 602, the integration operation is stopped and its output is in the hold state.

FIG. 7 is a block diagram of a disc player according to another embodiment of the present invention. The only difference from FIG. 1 is that the integrating means 8 is replaced by the time constant switching means 12, and the other operations are the same. That is, in the present embodiment, the integration time constant of the integrating means 8 becomes larger than that of the normal time by the time constant switching means 12 only for a predetermined period after the jump trigger is generated, and integration by an excessive error signal after the jump occurs. The change in the means output is suppressed. As a result, as in the case of FIG. 1, the residual error after the jump can be reduced and the spindle servo can be quickly returned to the normal state.

FIG. 8 shows an example of a circuit which constitutes the integrating means 8, the adding means 9 and the time constant switching means 12 in FIG.
In the figure, 801 is a one-shot monomulti, 80
Reference numeral 2 is a latch, 803 and 807 are adders, 804 is a selector, 805 is a clock generation circuit, and 806 is a multiplier. The operations of the integrating means 8 including the latch 802 and the adder 803, the multiplier 806 and the adder 807 are the same as in the case of FIG. For the two types of clocks having different frequencies generated by the clock generation circuit 805, the selector 804 selects and outputs the high-frequency clock signal on the A input side in the normal state to Y, but the jump trigger is input from 8b. And, Wantonto Mono Multi 801
Since a pulse having a fixed time width is output from the selector, the selector output is switched to a clock signal having a frequency lower than that of the B input side, that is, the A input side during that period. As a result, the integration time constant of the integrating means 8 increases for a certain period from the jump trigger.

The disc player of the present invention is not limited to the above embodiment, and the disc type may be magnetic type or electrostatic type, not limited to optical type.
The configuration of the reading unit 2 also changes accordingly.

Further, the intervals of the jump triggers generated by the trigger generating means 3 do not necessarily have to be constant. For example, after detecting that the spindle servo system has settled after the jump operation, a signal is reproduced for a fixed time and the jump is performed again. It is also possible to follow the algorithm.

Further, the jump operation by the position control means 4 is not limited to the method shown in FIG. 3, and any method can be used as long as the reproduction position can be forcibly moved.

The circuits shown in each of FIGS. 5, 6, and 8 are merely examples of specific circuit implementations, and are not limited to this configuration. For example, the integrating means 8 shown in FIG. 5 is a perfect integrating type, but the same effect can be obtained even if the DC gain is finite. The part that is in digital operation can be easily realized by software. The circuit shown in FIG. 8 can be configured by an analog circuit similar to that shown in FIG.

EFFECTS OF THE INVENTION As described above, the disc player of the present invention includes a reading unit that reads information from a disc on which information is recorded while changing the angular velocity on a concentric or spiral information track and outputs a reproduction signal, and externally. The trigger generating means for outputting a jump trigger in response to the operation of (1) and the information reading position by the reading means on a predetermined track, and when the jump trigger is input, the information reading position is the radius of the predetermined number of tracks. Position control means for forcibly moving in the direction, sync separation means for separating and outputting a sync signal included in the reproduction signal, reference generation means for outputting a reference signal that is a reference of the sync signal,
An error signal is output by comparing the frequency and / or phase of the synchronization signal and the reference synchronization signal with each other, rotation error detection means, integration means for integrating the error signal, and the error signal and the integrated error signal are added. An adding means, a driving means for rotationally driving the disk based on the output of the adding means, and an integration prohibiting means for holding the integrated output by stopping the integrating operation by the integrating means for a predetermined period from the jump trigger. Therefore, the disturbance of the spindle servo system after the jump operation can be suppressed, and the normal reproduction state can be returned more quickly.

[Brief description of drawings]

FIG. 1 is a block diagram of a disc player according to an embodiment of the present invention, FIGS. 2, 3, and 4 are waveform diagrams for explaining FIG. 1, and FIGS. FIG. 7 is a circuit diagram of an example forming a part of the figure, FIG. 7 is a block diagram of a disc player of another embodiment of the present invention, and FIG. 8 is a circuit diagram of an example forming a part of FIG. 1 ... Disk, 2 ... Read means, 3 ... Trigger generation means, 4 ... Position control means, 5 ... Sync separation means, 6 ...
Reference generating means, 7 ... Rotation error detecting means, 8 ... Integrating means, 9 ... Adding means, 10 ... Driving means, 11 ... Integrating inhibiting means, 12 ... Time constant switching means.

Continuation of front page (56) Reference JP-A-59-77673 (JP, A) Actually opened 61-149168 (JP, U) Actually opened 63-181152 (JP, U)

Claims (2)

[Claims] 1. A reading means for reading information from a disc on which information is recorded while changing an angular velocity on a concentric circle or a spiral information track and outputting a reproduction signal, and a jump trigger according to an operation from the outside. Position control for controlling the information reading position by the trigger generating unit and the reading unit on a predetermined track and forcibly moving the information reading position by a predetermined number of tracks in the disk radial direction when the jump trigger is input. Means and
Sync separation means for separating and outputting a sync signal included in the reproduction signal, reference generating means for outputting a reference signal which is a reference of the sync signal, frequency and / or phase of the sync signal and the reference sync signal And an error signal that outputs an error signal, an integrating device that integrates the error signal, an adding device that adds the error signal and the integrated error signal, and an output device based on an output of the adding device. A disc player comprising: a drive unit for rotating and driving a disc; and an integration prohibition unit for holding an integrated output by stopping the integration operation by the integration unit for a predetermined period from the jump trigger. 2. The disc player according to claim 1, further comprising, instead of the integration prohibiting means, a time constant switching means for making the integration time constant of the integration means larger than the normal time for a predetermined period from the jump trigger. .