JPH10340537A - Disk reproducing device and reproducing circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the quality by reducing the effect of a wobble component of a reproducing signal in a device for reproducing data synchronously with the wobble of a digital disk. SOLUTION: This reproducing device is provided with means 26, 28 for reproducing a wobble signal from a digital disk, a band pass circuit 23 containing a digital band pass filter that produces from the wobble signal a reference signal to be inputted in the PLL circuit 24 for generating a synchronous clock, means 26, 28 for reproducing an RF signal from the digital disk and a cancel means that removes or reduces the wobble component of the RF signal using the reference signal as a cancel signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for reproducing recorded data on a disk in synchronization with wobbles formed on the disk.

[0002]

2. Description of the Related Art As schematically illustrated in FIG. 10, a disk recording medium formed by meandering a wall portion of a groove to form a sine wave shape (wobble shape) having a certain period and amplitude. Are known. Such a wobble is described in, for example, Japanese Patent Application Laid-Open No. 7-311962 (G11B).
7/00) and are well known. Also,
In this wobble, address information is recorded.

[0003]

The applicant of the present invention has previously filed an application for an invention of a digital disk reproducing apparatus using an embedded clock system as a data reproducing synchronizing system (Japanese Patent Application No. 9-63406, Heisei Hei 9-63406). (Filed on March 17, 1997). In the specification of the application, a groove in which address information is recorded at predetermined intervals and wobbled by a clock of a single frequency serving as a reference when generating a bit clock at the time of disk rotation control and data recording / reproduction is described. A digital disk and a reproducing apparatus for the digital disk are described.

The above-mentioned reproducing apparatus reproduces the recorded data of the digital disk in synchronization with the wobble formed on the digital disk. However, since the period of the wobble is approximately the same as the period of the data bit, the reproduction is performed. There is a problem that the influence of the wobble signal appears strongly in the signal, which degrades the quality of the reproduced data. The present invention aims to solve this problem.

[0005]

According to the present invention, there is provided a reproducing circuit for removing or reducing a wobble component contained in a reproduced signal. The wobble component is a component that is superimposed on a reproduced signal by scanning a wobble formed in a meandering manner as shown in FIG. Elimination or reduction refers to reducing wobble components from the reproduced signal. According to the present invention, in the above-mentioned configuration, there is provided a reproducing circuit, wherein the wobble component has periodicity.
The term “periodic” refers to a case of a single-frequency clock serving as a reference when the above-described bit clock is generated.

According to the present invention, there is also provided a reproducing circuit, characterized in that a reproducing signal is obtained by dynamically scanning a recording medium. Recording media include magneto-optical disks, magnetic disks, optical disks, CD-Rs, and DVs.
D, CD-ROM, disk recording media / reproducing media such as phase-change optical disks, band-shaped recording media / reproducing media such as magnetic tapes and magneto-optical tapes such as DAT, and drum recording media / reproducing magnetic or magneto-optical. Refers to media and the like. Dynamic scanning means scanning by moving a recording medium along a groove / land where a wobble is formed with respect to a stationary head, and scanning / moving a groove / groove where a head is wobble with respect to a stationary recording medium. In some cases, scanning is performed by moving along a land. The scanning speed is determined, for example, by a clock recorded on the wobble according to the characteristics of the zone to which the specific scanning portion belongs.

Further, the present invention provides a reproducing circuit characterized in that the recording medium is a recording / reproducing medium, in other words, a recording / reproducing medium. Also,
According to the present invention, in the above-described configuration, there is provided a reproducing circuit, wherein recording is performed by magneto-optic, optical, or magnetic.
Magneto-optical recording is performed, for example, by directing the magnetization of a recording layer heated by laser light irradiation to the direction of an external magnetic field corresponding to data. Recording by light is performed, for example, by causing a phase change corresponding to data to occur in a recording layer by irradiation with laser light. Magnetic recording is performed, for example, by directing the magnetization of the recording layer in a direction corresponding to the data. Further, according to the present invention, in the above-mentioned configuration, as described above, the recording medium has a band shape, a disk shape, or a cylindrical shape.

The present invention also provides a reproducing circuit having the above structure, wherein the recording medium has grooves and / or lands as shown in FIG. Further, according to the present invention, in the above configuration, the groove and / or the land meanders in a direction in a recording medium plane orthogonal to the scanning direction (a direction along the groove). It is. In this case, meandering means that the wall of the groove or land has a certain period and amplitude, as shown in FIG.

Further, according to the present invention, in the above-mentioned structure, a cancel signal for reducing a wobble component from a reproduced signal in order to remove or reduce the wobble component dynamically scans the meandering, that is, a groove / land is formed. A reproduction circuit formed by performing scanning so as to detect a fluctuation corresponding to a wobble component when scanning along. Further, according to the present invention, in the reproducing circuit described above, the cancel signal is obtained by optical scanning, for example, scanning by laser light.

Further, the present invention is the reproduction circuit according to the above configuration, wherein the cancel signal is separated via a digital filter. A digital filter is a device that performs filtering and signal processing by algebraic operations (delay, addition, multiplication) as described in various books and the like, and has higher precision and no adjustment than analog filters. It has excellent flexibility and compatibility with LSI technology. "Excellent flexibility" means that various signal processing can be supported by using a DSP only by developing programs and exchanging coefficients. Therefore, even when a plurality of zones having different frequencies of the synchronous clock (wobble signal) exist in the same disk, it is possible to cope with the simple adjustment. According to the present invention, in the above-described configuration, there is provided a reproducing circuit, wherein the cancel signal is used to form a reproducing clock, that is, a bit clock for data reproduction.

The present invention also provides a reproducing circuit according to the above-mentioned configuration, wherein the wobble meanders are formed discontinuously, that is, there is a portion which does not correspond to a bit clock for data reproduction. is there. According to the present invention, in the above-mentioned configuration, there is provided a reproducing circuit, wherein the wobble meander has a discontinuous portion periodically. For example, there is a case where an address area is provided at regular intervals and the wobble shape of the address area is different from the wobble shape of another area (data area). Further, the present invention is the reproducing circuit according to the above configuration, wherein the discontinuous portion includes address information (positional information in the disk).

Further, the present invention is the reproducing circuit, characterized in that it has a compensating means for compensating for the loss of the cancel signal accompanying the reproduction of the discontinuous portion in the above configuration. When the wobble signal or the band-pass filter output of the wobble signal is used as the cancel signal, the cancellation signal is missing because the address area does not function as the cancel signal. Compensation means that a wobble signal or a band-pass filter output of the signal does not function as a signal, but instead uses a substitute signal functioning as a cancel signal.

Further, the present invention is the reproduction circuit according to the above-mentioned configuration, wherein the compensation means replaces the cancel signal with a pseudo signal, that is, the above-mentioned substitute signal when the cancel signal is lost. . According to the present invention, in the above-mentioned configuration, the reproducing circuit is characterized in that the pseudo signal is output by the digital synthesizing means. The digital synthesizing means is means for storing, for example, a wobble signal functioning as a cancel signal and a band-pass filter output of the signal, and using this as a pseudo signal.

The present invention also relates to an apparatus for reproducing recorded data on a disk by scanning a wobble formed on the disk, comprising: a wobble reproducing means for reproducing a wobble signal from the disk; PLL
Reference signal generating means for generating a reference signal to be input to a circuit from the wobble signal, data reproducing means for reproducing an RF signal from a disc, and removing a wobble component of the RF signal using the reference signal as a cancel signal Alternatively, it is a disk reproducing apparatus having a canceling means for reducing the number. Further, according to the present invention, in the above-mentioned configuration, there is provided a disk reproducing apparatus in which the reference signal generating means includes a digital bandpass filter.

Further, the present invention is a reproducing apparatus for scanning a wobble formed on a disk to reproduce recorded data of the disk and detecting a disk address from an address area of the wobble, wherein a wobble signal is transmitted from the disk. Wobble reproducing means for reproducing, area detecting means for detecting an address area from the wobble signal, reference signal generating means for generating a reference signal to be inputted to a PLL circuit for generating a synchronous clock from the wobble signal,
Pseudo signal generation means for generating a pseudo signal similar to the reference signal generated by the reference signal generation means immediately before the detection of the address area; and generation of the pseudo signal from the wobble signal for a predetermined period when the address area is detected. Switching means for converting the pseudo signal into a reference signal to be inputted to the PLL circuit in place of the reference signal to be inputted,
A disc reproducing apparatus comprising: data reproducing means for reproducing a signal; and canceling means for removing or reducing a wobble component of the RF signal using the reference signal as a cancel signal. Further, according to the present invention, in the above-mentioned configuration, there is provided a disk reproducing apparatus in which the reference signal generating means includes a digital bandpass filter.

Further, according to the present invention, in the above configuration, the pseudo signal generating means is a register provided in the reference signal generating means at a stage preceding the digital band pass filter, and the switching means is replaced with the wobble signal by the register. Is a disk reproducing apparatus for repeatedly inputting the above data over a predetermined period and inputting the data to the digital bandpass filter.

Further, according to the present invention, in the above configuration, the pseudo signal generating means is a register provided in the reference signal generating means at a stage subsequent to the digital band pass filter, and the switching means is connected to an output of the digital band pass filter. Instead, this is a disc reproducing apparatus that repeatedly outputs data of a register over a predetermined period.

Further, the present invention is the disk reproducing apparatus according to the above configuration, wherein the canceling means is means for level-converting the output of the digital bandpass filter and subtracting the level-converted output from the RF signal after A / D conversion. . Further, the present invention is the disk reproducing apparatus according to the above configuration, wherein the canceling means is a means for level-converting the output of the register and subtracting it from the RF signal after A / D conversion. Further, according to the present invention, in the above-mentioned configuration, the reference signal generation unit includes:
A disk reproducing apparatus including a delay adjuster that adjusts the total delay amount in the processing by the reference signal generation means to an integral multiple of one wave of the wobble signal to align the phases of the RF signal and the cancel signal.

[0019]

FIG. 10 schematically shows the surface of a magneto-optical disk 10 recorded / reproduced by a digital disk recording / reproducing apparatus according to an embodiment. This magneto-optical disk
In FIG. 10, grooves are engraved at a predetermined pitch in a spiral shape, and grooves and lands are formed by meandering (wobbling) both walls.

The frequency of the wobble is a single frequency (for example, 2 bytes of data equal to 1 byte) which is a reference when generating a bit clock for controlling the rotation of the disk and recording / reproducing data.
Frequency and a predetermined period (eg, 2K)
Address information is recorded for each byte. This is shown in FIG. In the case of a so-called zone disk, the wobble frequency differs between zones. Also,
The address information is recorded after being modulated using a bi-phase encoding method or the like.

FIG. 1 is a block diagram omitting a reproducing system of a magneto-optical recording / reproducing apparatus. The data to be recorded is input from an input terminal 14 and subjected to a code conversion process such as an error correction coding process or a modulation process for reducing the DSV by a modulation circuit 16, and then to a magnetic head 20 via an amplifier 18. Output
Thus, recording on the magneto-optical disk 10 is performed.

Data to be recorded is recorded in a data area of the magneto-optical disk 10 in synchronization with a clock reproduced from a wobble recorded on the magneto-optical disk 10. The write timing and recording clock for this purpose are supplied from the system controller 22 and the PLL circuit 24.

A wobble signal from the wobble engraved on the magneto-optical disk 10 is obtained by outputting an output from the optical head 26 through a matrix circuit 28. The matrix circuit 28 outputs a tracking error signal, a focus error signal, and an RF signal in addition to the wobble signal. The tracking error signal is a tracking control circuit
Sent to the optical head as a tracking control signal
Returned to 26. The focus error signal is sent to the focus control circuit 32 and returned to the optical head 26 as a focus control signal. At the time of reproduction, the RF signal is demodulated by a reproduction system circuit.

The wobble signal is supplied to the spindle servo circuit 34
Is input to The spindle servo circuit 34 controls the rotation of the motor 38 by comparing the wobble signal with a 1.1 [MHz] reference signal from the reference oscillator. That is, the rotation of the motor 38 is controlled so that the wobble signal and the 1.1 [MHz] reference signal are synchronized.

The wobble signal is supplied to an address detection circuit.
Entered in 40. Thereby, the address information multiplexed in the wobble signal in the biphase is detected. The detected address and the detection timing are sent to the system controller 22.

The wobble signal is supplied to a band-pass circuit 23.
, And is also input to the PLL circuit 24. Thereby, PL
The L circuit 24 outputs a 17.6 [MHz] clock phase-synchronized with the 1.1 [MHz] wobble signal. The band pass circuit 23 will be described later.

As described above, in the magneto-optical recording and reproducing apparatus shown in FIG. 1, data to be recorded is recorded on the magneto-optical disk 10 in synchronization with the clock signal synchronized with the wobble signal reproduced from the magneto-optical disk 10. You. That is, the data to be recorded is recorded in synchronization with the wobble shape.

FIG. 2 is a block diagram showing the recording system of the magneto-optical recording / reproducing apparatus with the recording system omitted. The data, as described above,
The data is recorded in the data area in synchronization with the wobble of the magneto-optical disk 10. The matrix circuit 28 outputs a tracking error signal, a focus error signal, and an RF signal in addition to the wobble signal. The tracking error signal is sent to the tracking control circuit 30 and returned to the optical head 26 as a tracking control signal. The focus error signal is sent to the focus control circuit 32 and returned to the optical head 26 as a focus control signal.

The wobble signal is supplied to the spindle servo circuit 34
Is input to The spindle servo circuit 34 controls the rotation of the motor 38 by comparing the wobble signal with a 1.1 [MHz] reference signal from the reference oscillator. That is, the rotation of the motor 38 is controlled so that the wobble signal and the 1.1 [MHz] reference signal are synchronized.

The wobble signal is supplied to an address detection circuit.
Entered in 40. Thereby, the address information multiplexed in the wobble signal in the biphase is detected. The detected address and the detection timing are sent to the system controller 22.

The wobble signal is supplied to the band pass circuit 23.
, And is also input to the PLL circuit 24. Thereby, PL
The L circuit 24 outputs a 17.6 [MHz] clock phase-synchronized with the 1.1 [MHz] wobble signal. The band pass circuit 23 will be described later.

The RF signal is reduced by an OP amplifier 41 from a cancel signal (a signal corresponding to a wobble component) output from the band-pass circuit 23 as described later, and then binarized by an A / D conversion circuit 42. . By reducing the cancel signal, as shown in FIG. 7, the wobble component is removed from the RF signal, and a good reproduced signal can be obtained. The binarized data is demodulated by the demodulation circuit 44 and restored to the original data.

As described above, in the magneto-optical recording / reproducing apparatus shown in FIG. 2, the recording data is reproduced in synchronization with the clock signal synchronized with the wobble signal reproduced from the magneto-optical disk 10. Also, at this time, the wobble component superimposed on the RF signal is removed or reduced by a cancel signal generated based on the wobble signal as described later, so that the characteristics of the reproduced signal are improved. Also, R
Since a clock component is included in the F signal, and a clock synchronized with the reproduction data can be obtained without creating a clock based on the clock component, sufficient recording and reproduction can be performed without considering the self-clock. There are also effects that can be realized.

Hereinafter, the band pass circuit 23 will be described. FIG. 3 is a block diagram showing an example of the band-pass circuit 23 in the reproducing circuit shown in FIGS. The wobble signal is
After A / D conversion by the A / D converter 231, the vicinity of a frequency component near the frequency of the wobble signal is extracted by the digital bandpass filter 233, and further, the phase difference from the RF signal is delayed by the delay unit 235. Thereafter, the D / A converter 236 performs D / A conversion. This output is used as a reference signal
The signal is input to the L circuit 24, whereby the PLL circuit 24 generates a reproduction clock and sends it to the A / D converter 42 and the demodulation circuit 44 in FIG. During recording, the PLL circuit 24 generates a recording clock and sends it to the modulation circuit 16 in FIG. The output of the PLL circuit 24 is frequency-divided into 1 / n by a frequency divider 238 and smoothed. Then, the A / D converter 231, the digital bandpass filter 233, the delay unit 235, and the D / A converter 236.

The output of the D / A converter 236 (the reference signal of the PLL circuit 24) is amplified to a predetermined level and then supplied to the OP amplifier 41 as a cancel signal. As a result, the OP amplifier 41 outputs a signal obtained by subtracting the cancel signal (wobble component) from the RF signal as a reproduction signal as shown in FIG. Further, the delay unit 235 is provided by R
In order to align the waveform phases of the F signal and the cancel signal, A
The total amount of delay from the / D converter 231 to the D / A converter 236 is inserted so as to be an integral multiple of the total number of samples for one wave of the wobble. When the clock changes in the middle like a so-called zone disk, the delay amount (α) is also changed appropriately. Such a delay unit 235 can be easily configured using a flip-flop. Further, since the digital bandpass filter 233 is used as described above, even when the clock changes halfway as in the above-mentioned zone disk,
It can be handled by a simple operation of changing the frequency of the sample clock, and the circuit scale is small.

FIG. 4 shows a circuit constructed in consideration of the fact that the above-mentioned cancel signal cannot be obtained in the address area. That is, as shown in FIG. 8, the wobble signal waveform in the address area is different from the wobble signal waveform in the data area. Therefore, when the above processing is performed, in the address area, the output from the digital bandpass filter 233 set so as to conform to the wobble signal is
As shown in FIG. 9, the cancel signal is almost lost, and the cancel signal cannot be generated. Therefore, the address area and the area affected by the address area (the digital bandpass filter 23)
In (3), the calculation is performed using the preceding and following data, which affects a certain range). In this case, a pseudo cancel signal is used.

That is, when the leading end (SYNC) of the address area is detected by the address area detecting circuit 239, the switch is switched so that the output of the register 232 is output repeatedly over a predetermined period. Therefore, the data immediately before the detection of the address area (for example, one wave of the wobble signal) is repeatedly output from the register 232, whereby a pseudo cancel signal is output. Other configurations are the same as those in FIG.

FIG. 5 is such that the register 232 is provided at the subsequent stage of the digital bandpass filter 233 in FIG. In this case, the same effect as in FIG. 4 is obtained.

FIG. 6 is a graph showing the relationship between R and R after A / D conversion in FIG.
This is an example in which a cancel signal is applied to the F signal. That is,
This is an example in which everything is processed with digital data. Since all of the processing is performed with digital data, the output of the digital bandpass filter 233 is delayed by the delay unit 235, and is further level-converted by the level converter 234 so as to conform to the RF data. Thereafter, the data is input to the subtractor 41a and is subtracted from the RF data. Thereby, the wobble component is canceled. Since the RF signal and the wobble signal are processed by the same clock, the frequency divider 238
Is not provided. In the case of FIG. 6 as well, the same effects as those of FIGS. 4 and 5 can be obtained, and the circuit configuration can be simplified.

Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, another type of circuit or device for reproducing a data recording medium on which data is recorded using light or magnetism, or another type of circuit or device for reproducing a cylindrical recording medium. It can also be applied to devices.

[0041]

According to the present invention, in a reproducing apparatus for reproducing recorded data of a disk in synchronization with a wobble formed on the disk and detecting a disk address from an address area of the wobble, the reproduced signal appears in a reproduced signal. Since the influence of the wobble signal can be canceled by the digital filter output of the wobble signal, the problem of deteriorating the quality of the reproduced data can be solved. Also, since a digital filter is used, even when the clock changes in the middle like a zone disk, only the frequency of the sample clock and the delay amount (α) need to be changed, so that the circuit scale can be easily increased. Can respond.

[Brief description of the drawings]

FIG. 1 is a block diagram omitting a reproduction system of a magneto-optical recording / reproduction device.

FIG. 2 is a block diagram omitting a recording system of the magneto-optical recording / reproducing apparatus.

FIG. 3 is a band-pass circuit 23 in the reproducing circuit shown in FIGS. 1 and 2;
FIG. 2 is a block diagram showing an example of the embodiment.

FIG. 4 is a band-pass circuit 23 in the reproducing circuit of FIGS. 1 and 2;
FIG. 4 is a block diagram showing an example different from FIG. 3.

FIG. 5 is a band-pass circuit 23 in the reproducing circuit shown in FIGS. 1 and 2;
FIG. 5 is a block diagram showing an example different from FIGS. 3 and 4.

FIG. 6 is a band-pass circuit 23 in the reproducing circuit shown in FIGS. 1 and 2;
FIG. 2 is a block diagram showing an example in which the entire circuit is configured by a digital circuit and subtracted from reproduced data after A / D conversion.

FIG. 7 is an explanatory diagram showing how a reproduction signal is obtained by subtracting a cancel signal from an RF signal.

FIG. 8 is an explanatory diagram showing an address area and a data area of a wobble signal.

FIG. 9 is an explanatory diagram showing how an address area of a wobble signal is replaced with a pseudo wobble signal of a data area.

FIG. 10 is an explanatory view schematically showing grooves and lands.

[Explanation of symbols]

 Reference Signs List 23 band-pass circuit 24 PLL circuit 40 address detection circuit 239 address area detection circuit

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Kenji Asano 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. No. 5 Sanyo Electric Co., Ltd.

Claims (27)

[Claims] 1. A reproduction circuit for removing or reducing a wobble component included in a reproduction signal. 2. The reproducing circuit according to claim 1, wherein the wobble component has a periodicity. 3. The reproduction circuit according to claim 1, wherein the reproduction signal is obtained by dynamically scanning a recording medium. 4. The reproduction circuit according to claim 3, wherein the recording medium is a rewritable medium. 5. The reproducing circuit according to claim 4, wherein the recording is performed by magneto-optical, optical, or magnetic. 6. The reproducing circuit according to claim 4, wherein the recording medium has a band shape, a disk shape, or a cylindrical shape. 7. The reproducing circuit according to claim 3, wherein the recording medium has a groove and / or a land. 8. The reproducing circuit according to claim 7, wherein the groove and / or the land meanders in a direction orthogonal to the scanning direction. 9. The reproducing circuit according to claim 8, wherein the cancel signal for removing or reducing the wobble component is formed by dynamically scanning the meander. 10. The reproducing circuit according to claim 9, wherein the cancel signal is obtained by optical scanning. 11. The reproducing circuit according to claim 10, wherein the cancel signal is separated via a digital filter. 12. The reproduction circuit according to claim 11, wherein the cancel signal is used to form a reproduction clock. 13. The reproduction circuit according to claim 8, wherein the meandering is formed discontinuously. 14. The reproducing circuit according to claim 13, wherein the meandering has a discontinuous portion periodically. 15. The reproducing circuit according to claim 14, wherein the discontinuous portion includes address information. 16. A reproducing circuit according to claim 13, further comprising a compensating means for compensating for a loss of a cancel signal accompanying reproduction of said discontinuous portion. 17. The reproducing circuit according to claim 16, wherein the compensator replaces the cancel signal with a pseudo signal when the cancel signal is lost. 18. The reproducing circuit according to claim 17, wherein the pseudo signal is output by digital synthesizing means. 19. A reproducing apparatus for reproducing wobble signals from a disk by scanning a wobble formed on the disk to reproduce recorded data on the disk, and a PLL circuit for generating a synchronous clock. Reference signal generating means for generating a reference signal to be input to the wobble signal from the wobble signal; data reproducing means for reproducing an RF signal from a disc; removing the wobble component of the RF signal by using the reference signal as a cancel signal; A disc playback device comprising: 20. A disc reproducing apparatus according to claim 19, wherein said reference signal generating means includes a digital band pass filter. 21. A reproducing apparatus for scanning a wobble formed on a disk to reproduce recorded data on the disk and detecting a disk address from an address area of the wobble, the wobble reproducing reproducing a wobble signal from the disk. Means, area detection means for detecting an address area from the wobble signal, reference signal generation means for generating, from the wobble signal, a reference signal to be input to a PLL circuit for generating a synchronous clock, detection of the address area A pseudo signal generating means for generating a pseudo signal similar to the reference signal generated immediately before by the reference signal generating means; and a reference signal generated from the wobble signal over a predetermined period when the address area is detected. Switching the pseudo signal to a reference signal to be input to the PLL circuit Disk reproducing apparatus having a stage, and a data reproducing means for reproducing an RF signal from the disk, and a canceling means for removing or reducing the wobble component of the RF signal using the reference signal as a cancellation signal. 22. The disc reproducing apparatus according to claim 21, wherein said reference signal generating means includes a digital band pass filter. 23. The pseudo signal generator according to claim 22, wherein the pseudo signal generator is a register provided in the reference signal generator before the digital band pass filter. Alternatively, a disc reproducing apparatus, wherein the data in the register is repeatedly input to the digital bandpass filter over the predetermined period. 24. The digital signal generator according to claim 22, wherein the pseudo signal generator is a register provided in the reference signal generator at a stage subsequent to the digital band pass filter. A disc reproducing apparatus, wherein data of the register is repeatedly output over the predetermined period in place of an output of a filter. 25. The RF device according to claim 23, wherein the canceling means converts the level of the output of the digital bandpass filter and performs A / D conversion.
A disc reproducing device that is a means for subtracting from a signal. 26. The disc reproducing apparatus according to claim 24, wherein the canceling means is a means for performing level conversion on the output of the register and subtracting the level from the RF signal after A / D conversion. 27. The method according to claim 19, wherein the reference signal generation means sets a total delay amount in the processing by the reference signal generation means to an integral multiple of one wave of the wobble signal. A disc reproducing apparatus including a delay adjuster that adjusts the phases of an RF signal and a cancel signal to adjust the phase.