JPH11203681A - Optical disk drive - Google Patents

Abstract

(57) [Problem] To solve the problem that a wobble signal band is shifted from a signal pass band of a band-pass filter for extracting a wobble signal. SOLUTION: A band-pass filter for extracting a wobble signal is constituted by an active filter circuit capable of changing a cut-off frequency, and a signal for controlling a cut-off frequency of the band-pass filter by using a dummy circuit based on the wobble signal. By providing the generated filter control circuit, even if the frequency of the wobble signal read from the optical disk changes, no inconvenience occurs because the signal pass band of the band-pass filter changes accordingly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus using an optical disk, and more particularly, to a wobble including a signal serving as a reference for recording / reproducing an information signal by undulating tracks formed on the disk. The present invention relates to an optical disk device that uses an optical disk on which a signal is recorded, and an optical disk device that can reproduce both an optical disk on which a wobble signal is recorded and an optical disk that does not use a wobble signal.

[0002]

2. Description of the Related Art As a conventional recordable / reproducible optical disk apparatus, a track on which an information signal formed on a disk is recorded as a pit train is undulated, and a signal or address information serving as a reference for recording / reproduction of the information signal is provided there. A device that records a wobble signal including the above is known. As an apparatus of this type, a technology disclosed in Japanese Patent Application Laid-Open No. 7-161132 is known.

[0003]

When a disk recorded at a constant linear velocity is read at a constant rotation speed during reproduction, a wobble signal or information read by an optical pickup is read between an inner peripheral portion and an outer peripheral portion of the disk. The frequency of the signal changes greatly. Further, even in the case where reproduction is performed at a constant linear velocity, when a track jump is performed from the inner circumference to the outer circumference or vice versa, reading is performed before the disk rotation speed converges to a predetermined value in order to speed up the reading. When processing is started from the above, a change in the read signal frequency occurs similarly. Further, as the disk rotation speed is increased to twice or three times the predetermined value in order to speed up the reproduction and reading, the frequency of the signal to be read is also increased by 2 times.
It changes twice and three times to a wide band.

Therefore, when a wobble signal is extracted from a signal read by an optical pickup, if the extraction filter is set to a narrow band, the wobble signal frequency deviates from the signal pass band of the extraction filter, and the wobble signal is attenuated. And no signal is extracted. Further, if the frequency band is widened, noise and other read signals are mixed with the wobble signal and output, so that there is a disadvantage that S / N is deteriorated. In addition, the position information or the like is inscribed as a pit at the beginning of the track, so that the track on which the wobble signal is recorded is intermittent, or the wobble signal at that portion is lost due to a defect such as a scratch.
/ N must be ensured and a response to signal loss is required.

In addition to the above-mentioned extraction filter, a circuit for processing a signal read from an optical pickup, for example, a waveform equalizer for emphasizing an attenuated high frequency band of a read information signal and correcting a frequency characteristic. Similarly, for a circuit or a phase-locked loop that reproduces a clock signal that is a reference for recording and reproducing information signals, the signal band read by the optical pickup and the circuit characteristic band need to match. .

Further, when integrating circuits such as the extraction filter and the waveform equalizing circuit, there are variations in the absolute values of the resistors and capacitor elements in the IC, so that the time constant characteristics using these elements vary. Inconvenience occurs.

When an optical disk device is used as an information storage device of a computer or the like, there is an optical disk of a system in which a wobble signal is not recorded, and it is necessary to be able to cope with such an optical disk.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an optical disk using an optical disk on which a wobble signal including a signal serving as a reference for recording and reproducing information is recorded by undulating tracks formed on the disk. In the apparatus, the first means includes at least a pickup circuit for reading a signal from the optical disk, an extraction filter capable of changing a time constant for extracting a wobble signal from the signal read by the pickup circuit, and a signal output from the extraction filter. A filter control circuit for generating a control signal in accordance with the frequency change of the wobble signal, and by controlling the time constant of the extraction filter with the control signal generated by the filter control circuit, the extraction filter always has the wobble signal frequency. It operates so that the time constant follows. This eliminates the inconvenience that the wobble signal band deviates from the signal pass band of the extraction filter, and also corrects the time constant fluctuation of the extraction filter due to variations in the absolute values of the resistors and capacitors when integrated. You.

In the above-mentioned optical disk apparatus, the second means may be a time constant circuit having a circuit configuration using a time constant element correlated with the extraction filter (for example, attenuation of an information signal read by a pickup circuit). (Waveform equalization circuit that emphasizes high-frequency band and corrects frequency characteristics, phase-locked loop circuit including oscillator that reproduces and outputs reference clock signal from wobble signal output from extraction filter, etc.)
By controlling the time constant of the extraction filter and the time constant circuit by the control signal generated by the filter control circuit, the operation of the time constant of the extraction filter always follows the wobble signal frequency, and the time constant circuit Of the signal band read from the optical disc and the characteristic band of the time constant circuit can be eliminated. The time constant fluctuation is similarly corrected.

In the optical disk apparatus, a third circuit includes a pickup circuit for reading at least a signal from the optical disk, a servo circuit for controlling a rotation speed of the optical disk and a position of an optical pickup included in the pickup circuit, and a pickup circuit. And a filter control circuit for generating a first control signal according to a frequency change of the wobble signal output from the extraction filter. The servo circuit generates a second control signal corresponding to the frequency of the wobble signal read from the optical disk based on the rotation speed of the optical disk and the position information of the optical pickup, and generates the first control signal and the second control signal. By controlling the time constant of the extraction filter by adding the control signal, The second control signal corrects the frequency change of the signal to be performed, and the first control signal corrects the time constant fluctuation due to the variation of the absolute value of the resistor and the capacitor element when integrated. , The wobble signal frequency and the time constant of the extraction filter can be matched over a wide range.

In the optical disk apparatus, a fourth circuit includes: a pickup circuit for reading a signal from the optical disk; a servo circuit for controlling a rotation speed of the optical disk and a position of an optical pickup included in the pickup circuit; A divider circuit for dividing and outputting a reference clock whose division ratio is controlled, a switching circuit for selectively outputting a signal read by a pickup circuit and an output of the divider circuit, An extraction filter that can change a time constant for extracting a predetermined signal band from an output signal of the switching circuit; a filter control circuit that generates a control signal according to a frequency change of a signal output from the extraction filter;
A time constant circuit having a circuit configuration using a time constant element having a correlation with the extraction filter; a control signal generated by the filter control circuit controls a time constant of the extraction filter and the time constant circuit; By controlling the frequency division ratio of the frequency division circuit based on the rotation speed of the optical pickup and the position information of the optical pickup, a signal having the same frequency as the wobble signal is generated from the frequency division circuit, and the switching circuit generates the wobble signal. When reading the recorded optical disk, the signal read out by the pickup circuit is selected and supplied to the extraction filter so that the time constant of the extraction filter follows the wobble signal frequency. When reading an optical disk of a system in which no wobble is recorded, a wobble signal pseudo-generated by the frequency dividing circuit is selected and supplied to the extraction filter. This allows the time constant of the extraction filter to follow the frequency of the wobble signal that has been pseudo-generated, so that even when there is no wobble signal, the same operation as when reading an optical disc on which a wobble signal is recorded is performed. Therefore, it is possible to cope with an optical disk of a system in which a wobble signal is not recorded.

The fifth means is an optical disk device, wherein at least a pickup circuit for reading a signal from the optical disk, a phase synchronization circuit for reproducing a synchronization clock phase-synchronized with the information signal read by the pickup circuit, A frequency dividing circuit for dividing the synchronous clock, a switching circuit for selectively outputting a signal read by the pickup circuit and an output of the frequency dividing circuit, and a time constant for extracting a predetermined signal band from an output signal of the switching circuit. A variable extraction filter,
A filter control circuit for generating a control signal in accordance with a frequency change of a signal output from the extraction filter, and a time constant circuit using a time constant element correlated with the extraction filter and capable of changing the time constant; The switching filter controls the time constant of the extraction filter and the time constant circuit by the control signal generated in the step (1). When reading the optical disk on which the wobble signal is recorded, the switching circuit selects and extracts the signal read by the pickup circuit. By supplying to the filter,
When the time constant of the extraction filter operates so as to follow the wobble signal frequency, and when reading an optical disk of a system in which no wobble signal is recorded, the frequency of a synchronous clock phase-synchronized with the information signal is divided by a frequency dividing circuit. By selecting the pseudo-generated wobble signal obtained by the above and supplying the same to the extraction filter, the operation is performed so that the time constant of the extraction filter follows the pseudo-generated wobble signal frequency, whereby even when there is no wobble signal, The operation can be performed in the same manner as when reading an optical disk on which a wobble signal is recorded, and it is possible to cope with an optical disk in which a wobble signal is not recorded.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an optical disk recording / reproducing apparatus (optical disk apparatus) according to the first embodiment of the present invention. In the figure, 1 is an optical disk, 2 is a spindle motor that supports and rotates the optical disk 1, and 3 is a pickup that reads an information signal recorded from the optical disk 1 and a wobble signal recorded as a swell of a track, amplifies the signal, and outputs the amplified signal. 4 is an AGC circuit that adjusts the signal amplitude to a constant value, 5 is a waveform equalization circuit that emphasizes and amplifies the high frequency band of the attenuated information signal, and 6 is
A signal detection circuit that converts the reproduced analog signal supplied from the waveform equalization circuit 5 into a digital signal that can be processed by a digital processing circuit, 7 is a phase synchronization circuit included in the signal detection circuit, and 8 is a signal read by the pickup circuit 3. A band-pass filter (extraction filter) composed of an active filter capable of varying a time constant for extracting a wobble signal from the output signal, and a dummy 9 composed of an active filter capable of varying a cut-off frequency, like the band-pass filter 8. Circuits, 10 and 13 are phase detection circuits, 11 and 1
4 is a low-pass filter, 12 is a filter control circuit for generating a signal for controlling the cut-off frequency of the band-pass filter 8, 15 is an oscillation circuit, 16 is a frequency dividing circuit, and 17 is a reproduction reference clock which is a reference from a wobble signal. The phase locked loop circuits T1 and T2 are output terminals.

In FIG. 1, a signal read from the optical disk 1 by a pickup circuit 3 is amplified, an information signal is supplied to an AGC circuit 4, and a reproduction signal including a wobble signal is supplied to a band-pass filter 8.

The information signal adjusted to a predetermined amplitude value by the AGC circuit 4 is input to the waveform equalizing circuit 5, where the attenuated high-frequency band is enhanced and corrected, and is supplied to the signal detecting circuit 6. The signal detection circuit 6 binarizes the supplied information signal for digital processing, generates a synchronization clock from the binarized information signal in the phase synchronization circuit 7, and outputs the synchronization clock to the output terminal T2. The information signal binarized by the synchronization clock is latched, and the synchronized information signal is output to the output terminal T1.

The band pass filter 8 extracts a wobble signal from the signal supplied from the pickup circuit 3, and the wobble signal is supplied to the dummy circuit 9 and the phase detection circuits 10 and 13, respectively.

The phase detection circuit 10 generates a signal corresponding to the phase difference between the supplied wobble signal and the signal supplied from the dummy circuit 9, and the low-pass filter 11 smoothes the output signal of the phase detection circuit 10, This low-pass filter 11
Is supplied to the dummy circuit 9 and the bandpass filter 8 as a signal for controlling the cutoff frequency. A filter control circuit 12 includes the dummy circuit 9, the phase detection circuit 10, and the low-pass filter 11.

The phase detecting circuit 13 generates a signal corresponding to the phase difference between the supplied wobble signal and the output signal of the frequency dividing circuit 16, and the low-pass filter 14 smoothes the output signal of the phase detecting circuit 13. This is supplied to the oscillation circuit 15 to control the oscillation frequency of the oscillation circuit 15. Oscillation circuit 1
The oscillation signal generated at 5 is supplied to a frequency dividing circuit 16 to divide the frequency, and at the same time, the phase synchronizing circuit 7 is used as a reference clock for pulling in the frequency of the phase synchronizing circuit 7.
Supplied to The phase detection circuit 13, the low-pass filter 14, the oscillation circuit 15, and the frequency division circuit 16 constitute a phase synchronization circuit 17.

Next, the operation of controlling the cutoff frequency of the bandpass filter 8 by the filter control circuit 12 will be described in detail. First, the dummy circuit 9 has a first-order phase shift circuit characteristic, and outputs the signal while changing the phase according to the frequency while maintaining the amplitude of the input wobble signal. When the control signal supplied from the low-pass filter 11 increases, the cutoff frequency of the dummy circuit 9 increases, and when the control signal supplied from the low-pass filter 11 decreases, the cutoff frequency of the dummy circuit 9 decreases. Become.

The horizontal axis represents the phase difference between the two input signals of the phase detection circuit 10, and the vertical axis represents the output signal of the phase detection circuit 10.
FIG. 2 shows a characteristic diagram. When the phase difference between the two input signals is π / 2 (point P in FIG. 2), the phase detection circuit 10 does not output a phase error signal, and the output signal of the low-pass filter 11 maintains a constant value. When the input signal phase difference is larger than π / 2, the output signal of the low-pass filter 11 is increased by the phase error signal from the phase detection circuit 10, and conversely, when the input signal phase difference is smaller than π / 2, The output signal of the low-pass filter 11 is designed to be small by the phase error signal from the phase detection circuit 10.

First, it is assumed that the wobble signal frequency has a value of f1. When the wobble signal is supplied to the dummy circuit 9, the phase difference between the input and output of the dummy circuit 9 becomes π.
When it is smaller than / 2, the phase error signal from the phase detection circuit 10 acts to reduce the output signal of the low-pass filter 11. Then, when the output signal of the low-pass filter 11 decreases, the cutoff frequency of the dummy circuit 9 is controlled to decrease, and when the cutoff frequency of the dummy circuit 9 decreases, the dummy circuit 9 at the frequency f1 is determined from the primary phase shift circuit characteristics. , The phase difference between the input and output becomes larger. This feedback loop operation is repeated, and when the phase difference between the input and output of the dummy circuit 9 eventually becomes π / 2, the phase error signal from the phase detection circuit 10 disappears, and the output signal of the low-pass filter 11 changes to the value at that time. Therefore, the phase difference between the input and output of the dummy circuit 9 is also held at π / 2.

Next, it is assumed that the wobble signal frequency has changed to a value f2 larger than f1. Then, the phase difference between the input and output of the dummy circuit 9 was π / 2 at the frequency f1, but became larger than π / 2 at the frequency f2.
The output signal of the low-pass filter 11 starts to rise due to the phase error signal from 0, and as a result, the cutoff frequency of the dummy circuit 9 is controlled to be high, and the phase difference between the input and output at the frequency f2 becomes π / 2. It's getting smaller. Eventually, when the phase difference between the input and output of the dummy circuit 9 at the frequency f2 becomes π / 2, the phase error signal from the phase detection circuit 10 disappears, and the output signal of the low-pass filter 11 retains the value at that time. Therefore, the phase difference between the input and output of the dummy circuit 9 is also maintained at π / 2.

As described above, the filter control circuit 12
At the input wobble signal frequency, the input / output phase difference in the dummy circuit 9 is controlled to be π / 2. That is, the cutoff frequency of the dummy circuit 9 follows the wobble signal frequency. Therefore, the dummy circuit 9
Is designed so that the center frequency of the pass signal band of the band-pass filter 8 to which the same control signal is applied becomes the wobble signal frequency when the phase difference between the input and output is .pi. / 2. By doing so, even if the wobble signal frequency fluctuates, the center frequency of the pass signal band of the bandpass filter 8 always matches the wobble signal frequency.

That is, the inconvenience that the wobble signal band is shifted from the signal pass band of the band-pass filter can be solved. As a result, it is not necessary to extend the signal pass band of the band-pass filter beyond the wobble signal band. There is an effect that it is possible to prevent noise and other readout signals from being mixed into the wobble signal and output to degrade S / N. In addition, since the cutoff frequency fluctuation of the bandpass filter 8 due to the variation in the absolute value of the resistor and the capacitor element in the case of integration is similarly corrected on the basis of the wobble signal frequency, it is suitable for integration.

FIG. 3 is a circuit diagram showing a configuration example of a primary phase shift circuit used as the dummy circuit 9 described in FIG. 1. In FIG. 3, Q1 to Q15 are transistors, C1 is a capacitor, and R1 to R7 are A resistor, 18 is an inverting amplifier, Vcc is a circuit power supply, A1 is a current source, T3 is an input terminal to which a wobble signal output from the band-pass filter 8 is supplied, T4
Is an output terminal of the primary phase shift circuit, and T5 is an input terminal to which a signal for controlling a cutoff frequency is supplied.

The input terminal T3 is connected to the base of the transistor Q1 and the input terminal of the inverting amplifier 18, a resistor R1 is connected between the emitters of the transistors Q1 and Q2, and the emitters of the transistors Q1 and Q2 are connected to the transistors Q14 and Q14. Each is connected to the collector of Q15. The collector of the transistor Q1 is
3 is connected to the base of the transistor Q7, and the collector of the transistor Q2 is connected to the base and collector of the transistor Q4 and the base of the transistor Q6. The emitter of transistor Q3 is connected to the emitter of transistor Q4 and the emitter of transistor Q5, and the base and collector of transistor Q5 are connected to circuit power supply Vcc. The emitter of the transistor Q6 is
Emitter of transistor Q7 and transistor Q11
The collector of transistor Q6 is connected to the base and collector of transistor Q8 and the base of transistor Q9, and the emitters of transistor Q8 and transistor Q9 are grounded to form a current mirror circuit. The collector of the transistor Q7 is
Connected to the collector of transistor Q9, the base of transistor Q10, and one end of capacitor C1. The other end of the capacitor C1 is connected to the output terminal of the inverting amplifier 18. The collector of the transistor Q10 is grounded, and the emitter of the transistor Q10 is connected to the circuit power supply Vcc via the current source A1, and at the same time, is connected to the output terminal T4 and the base of the transistor Q2. Transistor Q1
2, the base and collector are connected to the input terminal T5 and the base of the transistor Q11, and the emitters of the transistors Q11 and Q12 are connected to the circuit power supply Vcc via the resistors R2 and R3 to form a current mirror circuit. . The base of transistor Q13
The collector is connected to the circuit power supply Vcc via the resistor R4, and at the same time, is connected to the bases of the transistors Q14 and Q15, and the transistors Q13, Q14 and Q15
Are grounded via resistors R5, R6 and R7, respectively, to form a current mirror circuit.

Next, the operation will be described. First, assuming that the resistance of the resistor R4 is R ₄ , the resistance of the resistor R5 is R ₅ , the base-emitter voltage of the transistor Q13 is V _be , and the voltage of the circuit power supply Vcc is V _cc , the current I flowing through the transistor Q13 is _o is I _o = (V _cc −V _be ) / (R ₄ + R ₅ ) (1) Expression is represented by the above expression (1), and the resistance R5 and the resistances R6 and R7.
Are equal to each other, transistors Q14 and Q4 forming a current mirror with transistor Q13
To 15, the current I _o flows equals transistor Q13, which is the operating point current through transistor Q3, Q4 constantly.

Assuming that the value of the control current supplied to the input terminal T5 is 2 · _If , the transistors Q11 and Q1
The transistors Q6 and Q
7, the operating point current of each of the transistors Q6 and Q7 constantly flowing is _If .

It is well known that the circuit composed of the transistors Q3, Q4, Q6, Q7 is a circuit in which the current ratio flowing through the transistors Q6, Q7 changes according to the current ratio flowing through the transistors Q3, Q4. The currents flowing through the transistors Q3 and Q4 are represented by I ₁ and I ₂ ,
6, assuming that the currents flowing through Q7 are I ₃ and I ₄ , I ₁ : I ₂ = I ₄ : I ₃ (2) Equation (2)

When the ratio of the total current flowing through the transistors Q3 and Q4 to the total current flowing through the transistors Q6 and Q7 is M as shown in the following equation (3), M is the amplification factor of the signal current. Represent.

M = (I ₃ + I ₄ ) / (I ₁ + I ₂ ) = _If / _Io (3) As is apparent from the above equation (3), the control current supplied from the input terminal T5. By changing the value, the amplification factor M of the signal current is controlled.

The signal voltage input from the input terminal T3 is
The current is converted into a signal current by a differential pair circuit including transistors Q1 and Q2 and a resistor R1, and the transistors Q3 and Q3
4 and its signal current is M at transistors Q6 and Q7.
The signal current that has been converted to a multiplied signal current and flows through transistor Q6 flows through transistor Q9 via a current mirror circuit including transistors Q8 and Q9, and the difference current between the current flowing through transistor Q9 and the signal current flowing through transistor Q7. Flows into the capacitor C1, the signal current is extracted as an integrated voltage, and the integrated voltage is supplied to the output terminal T4 and the base of the transistor Q2 via the emitter follower circuit including the transistor Q10 and the current source A1. .

[0033] Now, when the differential voltage between the bases of the transistors Q1 and Q2 [Delta] V, the resistance value of the resistor R1 and R _1, the signal current flowing through the transistor Q3, Q4 I _1, I
₂ is: I ₁ = I _o + ΔV / R ₁ (4) I ₂ = I _o −ΔV / R ₁ (5) The above equations (4) and (5) are obtained, and the transistors Q6 and Q
The signal currents I ₃ and I ₄ flowing through 7 are given by: I ₄ = M · I ₁ = M (I _o + ΔV / R ₁ ) (6) I ₃ = M · I ₂ = M (I _o −ΔV / R ₁ ) Expression (7) Expressions (6) and (7) above.

[0034] From this, the signal current I _s flowing into the capacitor C1, the above (6) than to (7) _{below, I s = I 4 -I 3} = 2M · ΔV / R 1 ...... (8) formula above ( 8) It is represented by the equation.

Here, gm = 2M / R ₁ (9) In the expression (8), the above expression (8) is as follows: I _s = gm · ΔV (10) The above expression (10) is obtained. Is the transistor Q1
And the base between the difference voltage ΔV of Q2 indicates the transconductance value into a signal current Is flowing into the capacitor C1, the signal current I _s is taken as the integral voltage than capacitor C1.

That is, 19 shown by a broken line in FIG.
Is an amplifying circuit for converting a voltage input to a current and outputting the same, and constitutes an integrating circuit in combination with the capacitor C1.

Therefore, the signal input from the input terminal T3 is V _i , the signal output from the output terminal T4 is V _o , the value of the capacitor C1 is C ₁ , and the amplification factor of the inverting amplifier 18 is -1.
_{If, ΔV = V i -V o ......} (11) equation _{V o = -V o + {I} s / (S · C 1)} ...... (12) equation, however, S is the Laplace operator above ( 11) Formula, (12)
It becomes an expression.

According to the above equations (9) to (12),
When the transfer function H _{1 (s)} is obtained, H _{1 (s)} = V _o / V _i = (S−ωo) / (S + ωo) (13) Equation (13) is obtained, and the cutoff frequency ωo is Ωo = gm / C ₁ = 2M / (C ₁ · R ₁ ) (14) Equation (14) is obtained.

As is apparent from the above equation (13), the filter circuit shown in FIG. 3 has a first-order phase shift circuit characteristic in which the amplitude characteristic is flat and only the phase changes. From the equation, the cutoff frequency ωo, which is a parameter unique to the filter circuit, is equal to the low-pass filter 11 supplied from the input terminal T5 as shown in the equation (3).
The signal current amplification factor M is controlled and varied according to the control current value from

The band-pass filter 8 described with reference to FIG. 1 is also configured by using an integrating circuit in which an amplifying circuit 19 shown by a broken line in FIG. 3 and a capacitor are combined.
The operation described in FIG. 1 can be obtained. FIG. 4 shows an example of the configuration.

FIG. 4 is a block diagram showing an example of the configuration of the band-pass filter 8. In FIG. 4, T6 is an input terminal to which a reproduction signal supplied from the pickup circuit 3 is input, and T7 is an extracted wobble signal. T8 is an input terminal to which the control signal output from the low-pass filter 11 is supplied, and 21 and 22 convert the same input voltage as the amplifier circuit 19 shown by the broken line in FIG. The output amplifier circuit, C21 and C22 are capacitors, and Vb is a voltage source for providing a circuit operating potential.

In FIG. 4, the positive input terminal of the amplifier circuit 21 is connected to the voltage source Vb, the current output terminal of the amplifier circuit 21 is connected to the capacitor C21 and the positive input terminal of the amplifier circuit 22, and the other end of the capacitor C21 is connected to the other terminal. Connected to input terminal T6. The current output terminal of the amplifier circuit 22 is connected to the capacitor C22 and the output terminal T7, and is connected back to the negative input terminals of the amplifier circuit 21 and the amplifier circuit 22. The mutual conductance value of the amplifier circuits 21 and 22 is controlled by a signal input from the input terminal T8.

Now, the mutual conductance values of the amplifier circuits 21 and 22 are gm ₁ and gm ₂ , the capacitance values of the capacitors C21 and C22 are C ₂₁ and C ₂₂ , and the signal input from the input terminal T6 is V _i . When a signal output from the output terminal T7 and V _o, the transfer function H
_{2 (S)} is represented by the following equation.

[0044]

(Equation 1)

From the above equation (15), the circuit shown in FIG.
The cut-off frequency ωo, which is a parameter unique to the filter circuit, indicates the mutual conductance values gm ₂₁ and gm ₂₁ according to the control signal input from the input terminal T8, as shown in FIG.
₂₂ is controlled and variable.

FIG. 5 is a block diagram showing a configuration of an optical disk recording / reproducing apparatus according to a second embodiment of the present invention. In FIG. The description is omitted to avoid duplication (this is
The same applies to the following embodiments.)

In FIG. 5, reference numeral 23 denotes a waveform equalizing circuit in which the waveform equalizing circuit 5 described with reference to FIG. The output of the low-pass filter 11 is supplied to control the cutoff frequency. An oscillation circuit 24 has a control input whose oscillation frequency is controlled separately from the signal supplied from the low-pass filter 14. The output of the low-pass filter 11 of the filter control circuit 12 is supplied as the control input. Has a circuit configuration that is correlated with the time constant of the active filter used for the band pass 8.

When the frequency of the wobble signal read by the optical pickup changes, the frequency of the recording information signal supplied from the pickup circuit 3 to the waveform equalization circuit 23 via the AGC circuit 4 also changes. The frequency band to be emphasized and corrected by the equalizing circuit 23 also changes. Therefore, in the present embodiment shown in FIG. 5, by controlling the cutoff frequency of the waveform equalization circuit 23 in conjunction with the cutoff frequency of the bandpass filter 8,
It is possible to cope with a frequency change of the recording information signal. When these circuits are integrated, I
Fluctuations in the cut-off frequency of the waveform equalization circuit 23 due to variations in the absolute values of the resistance and capacitor elements in C can be corrected by using the characteristic of the resistor and capacitor element having a high precision in the IC, which is suitable for integration. It is.

In this embodiment, the oscillation circuit 2
4 is controlled by the output of the low-pass filter 11 of the filter control circuit 12, whereby the free-running frequency of the oscillation circuit 24 changes in accordance with the fluctuation of the wobble signal frequency. 1
7 has the effect of improving the frequency pull-in response due to the closed-loop operation of FIG.
Fluctuations in the free-running frequency of the oscillation circuit 24 due to variations in the absolute values of the resistances and capacitor elements in C can be corrected by utilizing the characteristic of the ICs in which the ratio accuracy of the resistances and capacitor elements is excellent, which is suitable for integration. .

If the phase synchronization circuit 7 has the same configuration as the above-described phase synchronization circuit 17, the oscillation frequency can be controlled in conjunction with the cut-off frequency of the band-pass filter 8, so that the same effect can be obtained. It is clear that this is done. That is, in addition to the above-described waveform equalizing circuit 23 and oscillation circuit 24, the present invention can be applied to other circuits using a time constant element having a correlation with the time constant of the active filter used for the bandpass filter 8.

FIG. 6 is a block diagram showing the configuration of an optical disk recording / reproducing apparatus according to a third embodiment of the present invention. In FIG. 6, T9 denotes an input terminal, and 20 denotes a signal input from the input terminal T9. A switch that is controlled to supply or cut off the output of the phase detection circuit 10 to the low-pass filter 11.

For example, when the position information of the disc is engraved as a pit at the beginning of each track, the track on which the wobble signal is recorded becomes intermittent, and the wobble signal is lost at the position where the position information is engraved. It can be considered. In this case, the feedback control loop in the filter control circuit 12 malfunctions due to the lack of the input signal serving as the reference of the filter control circuit 12. Therefore, in the present embodiment shown in FIG. 6, the switch 20 is opened by the signal input from the input terminal T9 and the output of the phase detection circuit 10 is cut off during the period when the wobble signal is lost. With such a configuration, it is possible to prevent the filter control circuit 12 from malfunctioning due to the lack of the wobble signal.

FIG. 7 is a block diagram showing the configuration of an optical disk recording / reproducing apparatus according to a fourth embodiment of the present invention. In FIG. 7, reference numeral 25 denotes a phase controlled by a signal input from an input terminal T9. A switch that supplies or cuts off the output of the detection circuit 13 to the low-pass filter 14.

In the present embodiment shown in FIG. 7, a switch 25 is added to the configuration of the third embodiment shown in FIG. 6, and when the wobble signal is lost, the input of the phase synchronization circuit 17 is changed. When the wobble signal is lost, the switch 25 is opened by a signal input from the input terminal T9 and the output of the phase detector 13 is cut off in order to prevent the phase locked loop from malfunctioning due to the disappearance. is there. With such a configuration, in addition to the effect of the third embodiment, there is an effect that a malfunction of the phase locked loop due to the lack of the wobble signal can be prevented.

FIG. 8 is a block diagram showing a configuration of an optical disk recording / reproducing apparatus according to a fifth embodiment of the present invention. In FIG. 8, reference numeral 26 denotes optically reading information from the optical disk 1 and converting the information into an electric signal. An optical pickup 27, an amplifier circuit for amplifying an electric signal from the optical pickup 26,
28 is a drive circuit for moving the position of the optical pickup 26, 29 is a drive circuit for rotating the spindle motor 2, 30 is a servo circuit, 31 is a reference oscillation circuit for generating a reference clock, and 32 is an addition circuit.

The spindle motor 2 is driven by the drive circuit 29 to rotate the optical disk 1 and supplies a signal corresponding to the number of rotations to the servo circuit 30. Optical pickup 26
Is read from the optical disc 1 while being driven by the drive circuit 28 to change its position, and the read signal is amplified by the amplifier circuit 27 and transmitted to the AGC circuit 4, the bandpass filter 8, and the servo circuit 30, respectively. Supplied.

The servo circuit 30 operates with the reference clock generated by the reference oscillation circuit 31, and
, The read address information obtained from the signal from the amplifier circuit 27, the information that the optical pickup 26 moves across the track, etc., and the wobble extracted by the band-pass filter 8. Based on the signal, the position of the optical pickup 26 via the drive circuit 28 and the rotational speed of the spindle motor 2 via the drive circuit 29 are controlled to respective predetermined values for keeping the linear velocity or the rotational speed constant.

That is, the servo circuit 30 has information such as the rotation speed of the optical disk 1 and the read position of the optical pickup 26. Since the information has a correlation with the frequency of the wobble signal, it is read from the optical disk 1. It is possible to estimate the frequency of the wobble signal.

Therefore, the servo circuit 30 generates a control signal corresponding to the wobble signal frequency read from the optical disk 1 from information such as the rotation speed of the optical disk 1 and the read position of the optical pickup 26, The cutoff frequency of the band pass filter 8 and the dummy circuit 9 is controlled by adding the control signal from the filter 11. Then, the band-pass filter 8 and the dummy circuit 9 are controlled by the servo circuit 30 with respect to a change in the frequency of the wobble signal read from the optical disk 1, and the band-pass due to variations in the absolute values of the resistors and capacitors when integrated. The cutoff frequency fluctuation of the filter 8 and the dummy circuit 9 is
The control is corrected by the control signal fed back from the controller.

By dispersing the correction function in this way, the control range can be expanded as compared with the case where correction is performed only by the filter control circuit 12. Further, when a wobble signal is missing due to a scratch or dirt on the optical disc 1, the servo circuit 30 determines the rotation speed of the optical disc 1 and the information such as the reading position of the optical pickup 26 immediately before the information cannot be read due to the scratch. Since the frequency of the wobble signal to be read can be estimated and a signal can be generated, by limiting the range of change of the control signal from the low-pass filter 11, it is possible to minimize a malfunction such as a significant shift in the cutoff frequency. There is an effect that can be done. Also, as described above, the addition circuit 32
, The time constants of the waveform equalization circuit 5 and the phase synchronization circuit 17 are controlled in the same manner as the bandpass filter 8,
It can follow the frequency change of the signal read from the optical disk, and can correct the absolute value variation of the resistor and the capacitor element when integrated.

FIG. 9 is a block diagram showing the configuration of an optical disk recording / reproducing apparatus according to the sixth embodiment of the present invention. In the present embodiment shown in FIG. 9, the circuit described with reference to FIG. 8 operates more stably against a lack of a read signal due to a scratch or dirt on the optical disc 1.

In FIG. 9, reference numeral 33 denotes a defect detection circuit. The signal supplied from the amplifier circuit 27 to the AGC circuit 4 is also supplied to the defect detection circuit 33, and the output of the defect detection circuit 33 controls the switch 20. I do.

When a waveform in which a signal is lost as shown in FIG. 10A is added to the input of the defect detection circuit 33, the output of the defect detection circuit 33 becomes as shown in the waveform of FIG. A signal which becomes Hi level only during a period during which the signal is lost occurs. While this signal is at the Hi level, the switch 20
By shutting off the output of the phase detection circuit 10, the output of the low-pass filter 11 can maintain the level before the signal loss occurs, so that a malfunction such as a shift in the cutoff frequency of the band-pass filter 8 due to the signal loss is caused. Can be prevented. Also, as described in FIG.
There is no need to limit the change width of the control signal from the low-pass filter 11, and the control range of the filter control circuit 12 can be widened. Further, the output of the defect detection circuit 33 can be supplied to the signal detection circuit 6 to prevent the phase synchronization circuit 7 from malfunctioning during a period in which a signal is lost.

FIG. 11 is a block diagram showing a configuration of an optical disk recording / reproducing apparatus according to a seventh embodiment of the present invention.
In the figure, 34 is a servo circuit, 35 is a frequency dividing circuit, 3
6 is a switching circuit, and T10 is an input terminal.

The servo circuit 34 is obtained by adding a signal output for controlling the frequency division ratio of the frequency dividing circuit 35 to the servo circuit 30 described with reference to FIG. The frequency division ratio is varied by the signal, and the frequency of the reference clock generated in the reference oscillation circuit 31 is divided. The switching circuit 36 selects one of the output of the amplifier circuit 27 and the output of the frequency dividing circuit 35 according to the switching signal supplied from the input terminal T10, and supplies the signal to the bandpass filter 8. When the switching circuit 36 selects the output of the amplifier circuit 27 and supplies the signal to the bandpass filter 8 by the switching signal supplied from the input terminal T10, the same operation as that described with reference to FIG. 8 is performed.

A signal for controlling the frequency dividing ratio of the frequency dividing circuit 35 is as follows.
As described with reference to FIG. 8, the output of the frequency dividing circuit 35 is output from the optical pickup 26 based on the rotation speed of the optical disc 1 and the information on the read position of the optical pickup 26 by the servo circuit 34.
, A pseudo wobble signal can be generated from the reference clock.

Now, even if the optical disc 1 does not record a wobble signal, the servo circuit 34
There is information on the rotation speed and the read position of the optical pickup 26. Therefore, a pseudo wobble signal is generated at the output of the frequency dividing circuit 35 in the same manner as when reading an optical disk in which a wobble signal is recorded. ing. In the case where the optical disc 1 does not record a wobble signal, a switching signal corresponding to the optical disc scheme is input from the input terminal T10 to select the output of the frequency dividing circuit 35 and send the signal to the bandpass filter 8. By supplying the time constant, the time constants of the band-pass filter 8, the waveform equalizing circuit 5, and the phase synchronization circuit 17 can be controlled in the same manner as in the case of reading the optical disk on which the wobble signal is recorded. In addition to following the change in the frequency of the signal to be received, it is possible to correct variations in the absolute values of the resistors and capacitor elements when integrated. That is, an optical disk of a system recording a wobble signal,
It is possible to realize an apparatus that can handle both optical disks of a system in which a wobble signal is not recorded.

FIG. 12 is a block diagram showing the configuration of an optical disk recording / reproducing apparatus according to the eighth embodiment of the present invention.
In the present embodiment shown in FIG. 12, the circuit described with reference to FIG. 11 operates more stably against a lack of a read signal due to a scratch or dirt on the optical disc 1.

In FIG. 12, reference numeral 37 denotes a defect detection circuit;
8 is a switching circuit. The signal supplied from the amplifier circuit 27 to the AGC circuit 4 is also supplied to the defect detection circuit 37, and one of the two detection outputs of the defect detection circuit 37 (FIG. 12).
B) shown in FIG. 12 is supplied to the switching circuit 38 and the signal detection circuit 6, and the other (c shown in FIG. 12) is supplied to the switch 20, the phase synchronization circuit 17 and the signal detection circuit 6. The switching circuit 38 is controlled by the switching signal supplied from the input terminal T10 and the detection output of the defect detection circuit 37, and selects one of the output of the amplification circuit 27 and the output of the frequency dividing circuit 35, and The signal is supplied to the pass filter 8.

The difference between the defect detection circuit 37 and the defect detection circuit 33 described with reference to FIG. 9 lies in that the defect detection circuit 37 has two detection outputs. When a waveform having a signal loss as shown in FIG. 13A is added to the input of the defect detection circuit 37, one of the outputs of the defect detection circuit 37 becomes
As shown in the waveform of FIG. 13B, a signal which becomes Hi level only during the period of signal loss is generated, and the other output is shown in FIG.
If the period during which the signal is lost is greater than τ, as shown in the waveform of c of FIG. 3, a signal that becomes Hi level by a constant value τ from the time when the signal loss occurs is generated. A signal which becomes Hi level only during a period during which the signal is lost is generated. Here, the waveforms a, b, and c shown in FIG. 13 correspond to the signals a, b, and c shown in FIG. 12, respectively.

In FIG. 12, the following operation is performed by the two detection outputs b and c of the defect detection circuit 37.

First, as the detection output c, a signal which becomes Hi level when a signal loss is detected is generated, and this signal causes the switch 20 to cut off the output of the phase detection circuit 10 so that the output of the low-pass filter 11 is changed. The signal is held at the level before the signal loss occurs, and the phase synchronization circuit 17 holds the operation by the detection output c as described with reference to FIG. However, even if the output of the phase detection circuit 10 is cut off, the output of the low-pass filter 11 changes with time due to leakage current or the like. c is returned from the Hi level to the Lo level, and the switch 20 supplies the output of the phase detection circuit 10 to the low-pass filter 11. Separately from this, the detection output b of the defect detection circuit 37 is a signal that goes high when a signal loss is detected, controls the switching circuit 38 by this signal, and is the output of the frequency dividing circuit 35. The pseudo wobble signal is converted to a band pass filter 8.
To supply. The switching circuit 38 gives priority to the control of the detection output b even if the switching circuit 38 is controlled to select the output of the amplifier circuit 27 by the switching signal supplied from the input terminal T10.

As a result, the detection output c becomes Hi at a constant value τ.
When the level returns to the Lo level, the pseudo-wobble signal is output from the band-pass filter 8 to compensate for the signal loss. Therefore, even when the period during which the signal loss occurs is long, malfunction is prevented. There is an effect that can be done.

FIG. 14 is a block diagram showing an example of the configuration of the defect detection circuit 37 described in FIG. 12. In FIG. 14, T11 is supplied with the output signal a of the amplifier circuit 27 described in FIG. Input terminals, T12 and T13 are output terminals for outputting the detection signals b and c described in FIG. 12, 39 is an AM detection circuit, 40 is a comparator, 41 is a voltage source, 42 is a monomultivibrator, and 43 is AND.
Circuit.

The signal a supplied from the input terminal T11 is
The signal is detected by the AM detection circuit 39 and supplied to the comparator 40. The output of the comparator 40 changes to the Hi level when the signal a decreases (the signal missing portion shown in FIG. 13) with reference to the voltage value of the voltage source 41, Output terminal T as detection signal b
Supply to 12. The output of the comparator 40 is supplied to the mono-multivibrator 42, and the mono-multivibrator 42 outputs a Hi-level signal by τ described in FIG. 13 from the time when the output of the comparator 40 changes from the Lo level to the Hi level. By ANDing the output of the comparator 40 and the output of the mono-multivibrator 42 with the AND circuit 43, a detection signal c can be obtained at the output terminal T13.

The defect detection circuit 37 shown in FIG.
Can also be used as the defect detection circuit 33 described with reference to FIG. 9, in which case, the output terminal T12 may be used as the output of the defect detection circuit 33.

FIG. 15 is a block diagram showing a configuration of an optical disk recording / reproducing apparatus according to the ninth embodiment of the present invention.
In FIG. 15, reference numeral 44 denotes a binarization circuit for binarizing an analog signal for digital processing of an information signal supplied to the signal detection circuit 6, and 45 latches the binarized information signal with a synchronous clock. And outputs the synchronized information signal to the output terminal T.
1 is a latch circuit for outputting a signal to a synchronous detection circuit 46 for detecting a synchronous signal inserted at a constant interval in the information signal.
Reference numeral 7 denotes a phase synchronization circuit for generating a reproduction reference clock from a synchronization signal. Reference numeral 48 denotes an output of the phase synchronization circuit 47 and a phase synchronization circuit 17 controlled by a signal input from an input terminal T10.
A switching circuit 49 for selecting one of the outputs from the binarizing circuit 44. The switching circuit 49 generates a synchronous clock phase-synchronized with the information signal from the binarizing circuit 44 while referring to the reproduction reference clock selected and output by the switching circuit 48. A synchronizing circuit, 50 is a frequency dividing circuit for dividing a synchronous clock, and 51 is a switch which selects either the output of the pickup circuit 3 or the output of the frequency dividing circuit 50 under the control of a signal input from an input terminal T10. Circuit.

If the optical disk 1 is an optical disk on which a wobble signal is recorded, the switching circuit 51 selects the output of the pickup circuit 3 according to the signal input from the input terminal T10 as shown in FIG. The filter control circuit 12 selects the output of the phase synchronization circuit 17 according to the frequency of the wobble signal extracted by the band-pass filter 8 in the same manner as described above.
The time constants of the band-pass filter 8, the waveform equalizing circuit 5, and the phase synchronization circuit 17 are controlled by the control signal generated as described above.

When the optical disk 1 is an optical disk using no wobble signal, the switching circuit 51 selects the output of the frequency dividing circuit 50 according to the signal input from the input terminal T10, and the switching circuit 48 selects the phase synchronizing circuit. 47 output is selected. The phase synchronization circuit 47 generates a reproduction reference clock from the synchronization signal detected by the synchronization detection circuit 46. Based on the frequency of the reproduction reference clock, the phase synchronization circuit 49 generates a synchronization clock phase-synchronized with the information signal. Occurs. Therefore, the frequency of the synchronous clock follows a read signal band that changes depending on the rotation speed of the optical disc 1 and the read position of the pickup circuit 3. Therefore,
By dividing the frequency of the synchronous clock by the frequency dividing circuit 50, a pseudo wobble signal as described with reference to FIG. 11 can be generated. However, in the present embodiment shown in FIG. 15, since the synchronous clock frequency itself follows the read signal band that changes depending on the rotation speed of the optical disc 1 and the read position of the pickup circuit 3, the frequency division ratio of the frequency divider circuit 50 Need not be variable and may be a constant value.

Thus, regardless of whether the optical disk 1 is an optical disk on which a wobble signal is recorded or an optical disk using no wobble signal, the signal band to be read and the characteristic band of the band-pass filter 8 and the waveform equalizing circuit 5 are used. Can be prevented from shifting, and similarly to the above-described embodiments, there is an effect that a time constant variation due to variation in absolute values of resistors and capacitor elements when integrated can be corrected.

Next, FIGS. 16, 17 and 18 show other examples of the configuration of the bandpass filter 8 serving as an extraction filter for extracting a wobble signal.

In FIG. 16, reference numeral 52 denotes a high-pass filter, and 53 denotes a low-pass filter. The read signal supplied from the pickup circuit 3 is input from the input terminal T6, and the high-pass filter 52 and the low-pass filter 5
The unnecessary signal band is suppressed in 3 and the extracted wobble signal is output from the output terminal T7. From the input terminal T8,
The control signal output from the filter control circuit 12 is supplied, and the cutoff frequency of the high-pass filter 52 and the low-pass filter 53 is controlled by the control signal, so that the cut-off frequency of the band-pass filter 8 described above is changed. Controlled.

As described above, by combining the high-pass filter 52 and the low-pass filter 53, it is easy to set characteristics as an extraction filter for extracting a wobble signal. The low-pass filter 5 suppresses the high-frequency suppression characteristic with respect to the wobble signal frequency by the filter 52.
3 can be set according to the characteristics.

In the example shown in FIG. 17, the time constant of the high-pass filter 52 shown in FIG. 16 is fixed. In FIG. 17, 54 is a capacitor, 55 is a resistor, 56 is a voltage source for supplying a bias, Reference numeral 57 denotes a high-pass filter including a capacitor 54, a resistor 55, and a voltage source 56.

In the example shown in FIG. 17, only the low-pass filter 53 controls the cut-off frequency by the control signal from the input terminal T8, and the low-pass suppression of the wobble signal frequency by the high-pass filter 57. The characteristics are fixed. This is because when unnecessary signal components in the low frequency range are low relative to the wobble signal frequency and information signal components are distributed in the high frequency range relative to the wobble signal frequency, only the suppression characteristics in the high frequency range relative to the wobble signal frequency are used for the optical disc. By following the fluctuation of the signal band read out from No. 1, there is an effect that the circuit configuration can be simplified. Further, by providing the capacitor 54 externally to the integrated circuit in the case of integration, there is an advantage that the cutoff frequency can be set by arbitrarily selecting the capacitance value of the capacitor 54 later.

In the example shown in FIG. 18, a trap filter 58 is added to the configuration of FIG. 16, and a trap filter 58 is inserted between the high-pass filter 52 and the low-pass filter 53. The cutoff frequency (trap frequency) is controlled by a control signal from the input terminal T8, similarly to the high-pass filter 52 and the low-pass filter 53.

In the example shown in FIG.
By setting the trap frequency according to 8 to the band of the information signal read from the optical disc 1, there is an effect that a stronger suppression characteristic can be obtained.

In each of the embodiments described above, an example of application to an optical disk recording / reproducing apparatus has been described. However, it is needless to say that the present invention can be applied to a read-only optical disk apparatus.

[0089]

As described above, according to the present invention, first, the first
By controlling the cut-off frequency of the band-pass filter with the control signal generated by the filter control circuit,
Since the cut-off frequency of the band-pass filter always operates so as to follow the wobble signal frequency, it is possible to eliminate the inconvenience that the wobble signal band and the signal pass band of the band-pass filter are shifted. This eliminates the need to extend the band beyond the wobble signal band, and has the effect of preventing S / N from deteriorating due to noise and other read signals mixed into the wobble signal and output. In addition, the cutoff frequency fluctuation of the band-pass filter due to the variation in the absolute value of the resistor and the capacitor element when integrated is similarly corrected, which is suitable for integration.

Second, the time constants of other time constant circuits can be controlled in conjunction with the band pass filter by the control signal generated by the filter control circuit, so that the wobble signal band and the signal passing through the band pass filter can be controlled. The deviation from the band can be prevented, and at the same time, the disadvantage that the signal band read from the optical disk and the characteristic band of the other time constant circuit deviate can be eliminated. Time constant fluctuations due to value variations have the effect of being similarly corrected, and are suitable for integration.

Third, the cut-off frequency of the band-pass filter is controlled by the first control signal generated by the filter control circuit and the second control signal generated by the servo circuit, so that the optical disk can be controlled from the optical disk. The second control signal corrects the change in the frequency of the signal to be read, and performs the dispersion operation so that the first control signal corrects the change in the cutoff frequency due to the variation in the absolute value of the resistor or the capacitor element. Therefore, there is an effect that the wobble signal band and the signal pass band of the band-pass filter are matched over a wide range.

Fourth, when reading an optical disk of a system in which a wobble signal is not recorded, a wobble pseudo-generated by a frequency dividing circuit for controlling a frequency dividing ratio by a servo circuit to divide a reference clock. By using signals,
Since the same operation as in the case of reading an optical disk on which a wobble signal is recorded is performed, there is an effect that an optical disk recording / reproducing apparatus which can support optical disks of different systems can be provided.

Fifth, when reading an optical disk of a system in which a wobble signal is not recorded, a wobble signal pseudo-generated by a frequency dividing circuit for dividing a synchronous clock phase-synchronized with the information signal is used. Therefore, the same operation as when reading an optical disk on which a wobble signal is recorded is performed, so that there is an effect that an optical disk recording / reproducing apparatus that can support optical disks of different types can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between an input signal phase difference and an output signal (phase error signal) in the phase detector 10 in FIG.

FIG. 3 is a circuit diagram showing a configuration example of a dummy circuit 9 in FIG.

FIG. 4 is a circuit diagram showing a configuration example of a bandpass filter 8 in FIG.

FIG. 5 is a block diagram illustrating a configuration of an optical disc recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of an optical disc recording / reproducing apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram illustrating a configuration of an optical disc recording / reproducing apparatus according to a fifth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to a sixth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing waveforms of an input signal and an output signal in the defect detection circuit 33 in FIG.

FIG. 11 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to a seventh embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to an eighth embodiment of the present invention.

13 is an explanatory diagram showing waveforms of an input signal and an output signal in the defect detection circuit 37 in FIG.

14 is a block diagram showing one configuration example of a defect detection circuit 37 in FIG.

FIG. 15 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to a ninth embodiment of the present invention.

FIG. 16 is a block diagram showing another configuration example of the bandpass filter 8 serving as an extraction filter.

FIG. 17 is a block diagram showing another configuration example of the bandpass filter 8 serving as an extraction filter.

FIG. 18 is a block diagram illustrating another configuration example of the bandpass filter 8 serving as an extraction filter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 optical disk 3 pickup circuit 4 AGC circuit 5 waveform equalization circuit 6 signal detection circuit 7 phase synchronization circuit 8 bandpass filter 9 dummy circuit 10 phase detection circuit 11 low-pass filter 12 filter control circuit 13 phase detection circuit 14 low-pass filter 15 oscillation circuit 16 Divider 17 Phase synchronization circuit

Claims (9)

[Claims] 1. An optical disc apparatus using an optical disc on which a wobble signal including a signal serving as a reference for recording / reproducing an information signal by recording a wobble signal on a track formed on the disc is provided. Circuit for extracting the wobble signal from the signal read by the pickup circuit, and an extraction filter capable of varying a time constant, and a control signal corresponding to a frequency change of the wobble signal output from the extraction filter And a control signal generated by the filter control circuit.
An optical disc device, wherein a time constant of the extraction filter is controlled. 2. An optical disk apparatus using an optical disk on which a wobble signal including a signal serving as a reference for recording / reproducing an information signal by undulating tracks formed on the disk is used, at least a signal from the optical disk. Circuit for extracting the wobble signal from the signal read by the pickup circuit, and an extraction filter capable of varying a time constant, and a control signal corresponding to a frequency change of the wobble signal output from the extraction filter And a time constant element using a time constant element that is correlated with the extraction filter, the time constant of the filter control circuit can be varied, by the control signal generated by the filter control circuit,
An optical disc device, wherein a time constant of the extraction filter is controlled, and a control signal generated by the filter control circuit is used as a means for controlling a time constant of the time constant circuit. 3. An optical disk apparatus using an optical disk on which a wobble signal including a signal serving as a reference for recording / reproducing an information signal by undulating a track formed on the disk is recorded. A servo circuit for controlling a rotation speed of the optical disc and a position of an optical pickup included in the pickup circuit, and a time constant for extracting the wobble signal from a signal read by the pickup circuit. And a filter control circuit that generates a first control signal according to a frequency change of the wobble signal output from the extraction filter. The servo circuit includes a rotation speed of the optical disc and a rotation speed of the wobble signal. From the optical disc based on the position information of the optical pickup, The according to the frequency of the Desa see the wobble signal 2
An optical disc apparatus, wherein the control signal is generated, and the time constant of the extraction filter is controlled by the first control signal and the second control signal. 4. An optical disk apparatus using an optical disk, comprising: a pickup circuit for reading a signal from the optical disk; a servo circuit for controlling a rotation speed of the optical disk and a position of an optical pickup included in the pickup circuit; A reference oscillation circuit for generating a clock, a frequency division circuit for dividing the reference clock with a frequency division ratio being controlled, and a switch for selectively outputting a signal read by the pickup circuit and an output of the frequency division circuit A circuit, an extraction filter that extracts a predetermined signal band from the output signal of the switching circuit and can vary the time constant, a filter control circuit that generates a control signal according to a frequency change of a signal output from the extraction filter, Using a time constant element having a correlation with the extraction filter, a time constant circuit capable of changing the time constant. For example, the control signal generated by the filter control circuit,
Along with controlling the time constant of the extraction filter, a control signal generated by the filter control circuit is used as one means for controlling the time constant of the time constant circuit. The frequency division ratio of the frequency division circuit is controlled based on the position information of the optical pickup, and the switching circuit undulates a track formed on the disk to generate a signal serving as a reference for recording / reproducing an information signal. When reading an optical disk on which a wobble signal including the wobble signal is recorded, a signal read by the pickup circuit is selected and supplied to the extraction filter, and the switching circuit does not record the wobble signal. An optical disk device for selecting an output signal of the frequency dividing circuit and supplying the selected signal to the extraction filter when reading an optical disk of the system 5. An optical disk device using an optical disk, comprising: a pickup circuit for reading a signal from the optical disk; a phase synchronization circuit for reproducing a synchronization clock phase-synchronized with the information signal read by the pickup circuit; A frequency dividing circuit for dividing a synchronous clock, a switching circuit for selectively outputting a signal read by the pickup circuit and an output of the frequency dividing circuit, and extracting a predetermined signal band from an output signal of the switching circuit. An extraction filter having a variable time constant, a filter control circuit for generating a control signal corresponding to a frequency change of a signal output from the extraction filter, and a time constant element having a correlation with the extraction filter, wherein the time constant is variable A time constant circuit, wherein the switching circuit undulates tracks formed on the disk. When reading an optical disc on which a wobble signal including a signal serving as a reference for recording / reproducing a notification signal is read, a signal read by the pickup circuit is selected and supplied to the extraction filter, A control signal corresponding to a frequency change of the wobble signal generated by the control circuit controls a time constant of the extraction filter, and a control signal corresponding to a frequency change of the wobble signal generated by the filter control circuit. Used as one means for controlling the time constant of the time constant circuit, and the switching circuit selects an output signal of the frequency dividing circuit when reading an optical disc in which the wobble signal is not recorded. To the extraction filter, and by a control signal corresponding to a frequency change of the synchronous clock generated by the filter control circuit. In addition to controlling the time constant of the extraction filter, a control signal according to a frequency change of the synchronous clock generated by the filter control circuit is used as one means for controlling the time constant of the time constant circuit. Optical disk device. 6. The wobble according to claim 1, wherein the filter control circuit is a dummy circuit including a filter circuit to which the wobble signal is supplied and the same time constant as the extraction filter can be varied. A phase detection circuit that generates a signal corresponding to the phase difference between the signal and the output of the dummy circuit; and a low-pass filter that outputs a signal obtained by smoothing the output of the phase detection circuit. Means for controlling a time constant of the extraction filter and the dummy circuit as a control signal generated in a control circuit, and interrupting an output of the phase detection circuit to fix and maintain an output level of the low-pass filter. An optical disc device characterized by the above-mentioned. 7. The phase synchronization circuit according to claim 2, wherein the time constant circuit is a phase synchronization circuit that reproduces and outputs a clock signal serving as a reference for recording and reproducing information from the wobble signal output from the extraction filter. A synchronization circuit for generating the clock signal as an output, a frequency divider for dividing the clock signal, and a signal corresponding to a phase difference between the wobble signal and the output of the frequency divider; A phase detection circuit, comprising a low-pass filter for smoothing the output of the phase detection circuit and controlling the frequency of the clock signal generated by the oscillation circuit, by a control signal generated by the filter control circuit,
Along with controlling the time constant of the extraction filter, a control signal generated by the filter control circuit is used as one unit for controlling the free-running frequency of the oscillation circuit, and the output of the phase detection circuit is cut off. An optical disc device comprising: means for maintaining a fixed output level of a low-pass filter. 8. The filter control circuit according to claim 3, wherein the filter control circuit includes a dummy circuit including a filter circuit to which the wobble signal is supplied and the same time constant as the extraction filter can be varied, and a filter circuit for the wobble signal and the dummy circuit. A phase detection circuit that generates a signal corresponding to the phase difference of the output, and a low-pass filter that outputs a signal obtained by smoothing the output of the phase detection circuit, wherein an output of the low-pass filter is the first control signal; A time constant of the extraction filter and the dummy circuit is controlled by a first control signal and the second control signal, and an output of the phase detection circuit is cut off to keep the output level of the low-pass filter fixed. An optical disk device comprising means. 9. The switching circuit according to claim 4, wherein the switching circuit selects a signal read by the pickup circuit and supplies the signal to the extraction filter when reading an optical disk on which a wobble signal is recorded. Further, the switching circuit is adapted to output an output signal of the frequency dividing circuit during a period in which a read signal is lost during reading of an optical disk on which a wobble signal is recorded, or when reading an optical disk in which a wobble signal is not recorded. An optical disc device, wherein the selected optical disc is supplied to the extraction filter.