JP2009015988A - Optical disc apparatus, signal processing apparatus, and signal processing method - Google Patents

Abstract

The present invention provides a configuration that enables CAPA detection using a common circuit with other signal processing circuits.
A CAPA detection circuit generates a DC-cut push-pull signal generated by a signal processing circuit that shares a processing circuit for CAPA detection recorded on a disc and a processing circuit for wobble signal detection processing. Input, generate a peak / bottom difference signal [Spek−Sbtm] by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak], and binarize the threshold value of the peak / bottom difference signal [Spek−Sbtm]. To generate a CAPA signal. With this configuration, even when a waveform distortion due to DC cut occurs, a CAPA signal is generated without any problem and accurate control is realized.
[Selection] Figure 7

Description

  The present invention relates to an optical disc device, a signal processing device, and a signal processing method. More specifically, the present invention relates to an optical disc apparatus, a signal processing apparatus, and a signal processing method that perform optical pickup control by detecting CAPA (Complementary Allocated Pit Addressing) in an optical disc apparatus that performs data recording on an optical disc or data reproduction processing from the optical disc.

  Various optical disks such as CDs and DVDs are used as information recording media. When recording or reproducing data on or from an optical disk, it is necessary to control the optical pickup to be located at the center of the track of the disk, that is, the track center. As this pickup control method, there is a method using CAPA (Complementary Allocated Pit Addressing) as address information recorded in advance on an optical disc.

  A pickup control method based on detection of CAPA as address information recorded on the disc will be described. FIG. 1 shows a track 101 set on an optical disc and a light spot 102 irradiated from an optical pickup applied to data recording or reproduction processing for the track. A header field 110 is set in the track 101, and CAPA is recorded in advance in the header field 110.

  As shown in the figure, the CAPA is composed of two CAPAs 111 and 112 that are shifted from the track center in different directions. As shown in FIG. 2, the reproduction signal generated by the irradiation of the light spot 102 is executed as a process of reading the spot light for each of the areas A, B, C, and D divided into four parts. Execute and analyze the read signal when passing through the CAPA 111 area of the header field shown in FIG. 1 and the read signal when passing through the CAPA 112 area of the header field, and calculate the amount of deviation of the light spot from the track center. The pickup is controlled by the track center.

  That is, the A and D sides of the four divided areas A, B, C and D are the area side of the CAPA 111 of the header field shown in FIG. 1, and the B and C sides are on the area side of the CAPA 112 of the header field shown in FIG. The push-pull signal [(A + D) − (B + C)] is generated in the signal processing circuit of the disk device, and the amount of deviation from the track center is calculated based on the change in this signal, and the pickup is connected to the track center. It is the structure controlled to.

  The track 101 is configured as a meandering track, that is, a track in which a so-called wobble is formed. The meandering is set to have a constant frequency at a constant linear velocity, the signal based on wobble is read from the track during recording / reproduction by the optical pickup, and the number of revolutions of the disk is maintained so that the read signal is kept at a constant frequency. By performing control or the like, the recording / reproducing process is performed at a constant linear velocity. This enables information recording with the same density from the inner periphery to the outer periphery of the disc.

  A control configuration example based on CAPA detection and wobble signal detection will be described with reference to FIGS. FIG. 2 shows a detailed configuration of the optical pickup in the optical disc apparatus, and FIG. 3 shows a general configuration of a wobble signal processing circuit and a CAPA detection signal generation circuit in the signal processing circuit of the optical disc apparatus.

  In FIG. 2, the laser light generated from the laser 155 of the optical pickup 157 is applied to the optical disc 151 through the collimator lens 154, the half prism 153, and the objective lens 152.

  The reflected light from the optical disk 151 is guided to the optical sensor 156 inside the optical pickup via the objective lens 152 and the half prism 153. The optical sensor 156 is divided into four regions A, B, C, and D, and RF signals A, B, C, and D are obtained.

  Next, an example of CAPA detection and wobble signal detection processing in a conventional system will be described with reference to FIG. The RF signal detected by the optical sensor is input to a wobble signal processing circuit 170 and a CAPA detection signal generation circuit 190, respectively.

  The RF signals (A, B, C, D) input to the wobble signal processing circuit 170 are added by the adder circuits 171 and 172, respectively, and a signal (A + D) and a signal (B + C) are generated. These signals (A + D) and (B + C) are subtracted after the DC components are cut by high-pass filters (HPF) 173 and 174 and further adjusted to appropriate amplitudes by gain control amplifiers (GCAs) 175 and 176. A push-pull signal [(A + D) − (B + C)] is generated by the circuit 177.

  The push-pull signal [(A + D) − (B + C)] has its DC component cut by a high-pass filter (HPF) 178 and is adjusted to an appropriate amplitude by a gain control amplifier (GCA) 179. The output of the gain control amplifier (GCA) 179 is input to the band pass filter (BPF) 180.

  The band pass filter (BPF) 180 extracts only the signal component of the wobble band from the input signal, and inputs the extracted signal to the comparator (Comp) 181. The comparator (Comp) 181 executes a binarization process using a predetermined threshold value, generates a binarization pulse, and outputs it to the PLL. In the PLL, control is executed by generating a signal for controlling the disk rotation speed, for example, in accordance with the input binary pulse.

  On the other hand, the four RF signals A, B, C, and D from the optical pickup input to the CAPA detection signal generation circuit 190 are added by the addition circuits 191 and 192 to generate a signal (A + D) and a signal (B + C). Is done.

  The signal (A + D) and the signal (B + C) are adjusted to appropriate amplitudes by the gain control amplifiers (GCAs) 193 and 194, and then subtracted by the subtracting circuit 195, whereby the push-pull signal [(A + D) − (B + C) ] Is obtained.

  The push-pull signal [(A + D) − (B + C)] is adjusted to an appropriate amplitude by the gain control amplifier (GCA) 196 and input to the CAPA detection circuit 197. The CAPA detection circuit 197 calculates, based on the push-pull signal [(A + D) − (B + C)], whether the optical pickup is at the track center, or is shifted, and if so, how much is shifted. The CAPA signal applied to set the optical pickup at the center of the track is output.

  As an example of CAPA signal generation processing in the CAPA detection circuit 197, the push-pull signal [(A + D) − (B + C)] is further input to the comparator, binarized with a predetermined threshold value, and the binarized signal is output. There is a configuration. About this structure, it describes in patent document 1 (Unexamined-Japanese-Patent No. 2004-192729), for example. A CAPA detection circuit configuration for generating such a CAPA signal will be described with reference to FIGS.

  FIG. 4 shows a circuit for inputting a push-pull signal [(A + D) − (B + C)] and outputting a binarized high level CAPA signal and a binarized low level CAPA signal. In FIG. 4, a peak hold circuit 201 generates a signal [Speak] obtained by holding the peak level of the push-pull signal, and a comparator 203 compares the peak hold signal [Speak] with a certain threshold level [SPref] to obtain a binary value. By doing so, a high-level binary CAPA signal is generated.

  On the other hand, the bottom hold circuit 202 generates a signal [Sbtm] that holds the bottom level of the push-pull signal [(A + D) − (B + C)], and the comparator 204 generates the bottom hold signal [Sbtm] at a certain threshold level [ Compared with SBref], a binarized CAPA signal on the low level side is generated by binarizing.

  FIG. 5 shows a signal processing for inputting a push-pull signal [(A + D) − (B + C)] as shown in FIG. 4 and outputting a binarized high level CAPA signal and a binarized low level CAPA signal. It is a figure explaining the signal waveform at the time of composition, and (1) does not perform DC cut to a push pull signal, and outputs a binarized high level CAPA signal and a binarized low level CAPA signal (2) represents a waveform when a high-level CAPA signal binarized by DC-cutting the push-pull signal and a binarized low-level CAPA signal are output.

  As shown in FIG. 5A, when CAPA detection is performed without performing DC cut, CAPA can be detected correctly if an appropriate threshold level is set. On the other hand, as shown in FIG. 5 (2), when the high-level CAPA signal binarized by DC-cutting the push-pull signal and the binarized low-level CAPA signal are output, the CAPA waveform is distorted. As a result, the pulse widths of the CAPA detection signals on the high level side and the low level side become extremely narrow, and the CAPA may not be detected correctly.

  In the signal processing circuit shown in FIG. 3 described above, the RF signals A, B, C, and D input to the wobble signal processing circuit 170 are added by the addition circuits 171 and 172, respectively, and the signal (A + D) and the signal ( After the (B + C) is generated, these signals (A + D) and (B + C) are configured such that the DC components are cut by the high-pass filters (HPF) 173 and 174. Such a process is performed because the circuit cannot be offset unless the DC is cut and a dynamic range is also required. However, as described with reference to FIG. 5, the CAPA detection signal generation circuit attempts to output a high-level CAPA signal that is binarized by DC-cutting the push-pull signal and a binarized low-level CAPA signal. Then, the waveform of the CAPA section is distorted, and the pulse widths of the CAPA detection signals on the high level side and the low level side become extremely narrow, and the CAPA may not be detected correctly.

If the CAPA detection signal generation circuit is configured to perform processing on the signal subjected to the DC cut processing, the circuit from the addition circuit to the gain control amplifier (GCA) in each of the processing circuits 170 and 190 shown in FIG. However, as explained with reference to FIG. 5B, the waveform of the CAPA section is distorted, and the pulse widths of the CAPA detection signals on the high level side and the low level side become extremely narrow. There is a problem that CAPA is not correctly detected, which hinders common use of circuits.
JP 2004-192729 A

  The present invention has been made in view of the above-described problems. An optical disc apparatus having a processing circuit that realizes downsizing and low cost by sharing a wobble detection circuit and a CAPA detection signal generation circuit. An object is to provide a processing device and a signal processing method.

  It is another object of the present invention to provide an optical disc apparatus, a signal processing apparatus, and a signal processing method that realize high-accuracy CAPA detection using a signal subjected to DC cut processing even in a CAPA detection signal generation circuit. .

The first aspect of the present invention is:
An optical disc apparatus that executes data recording or reproduction processing using an optical disc,
A signal processing circuit for performing a wobble signal detection process of a data track recorded on the disc and generating a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc;
A CAPA detection circuit that inputs a CAPA detection signal generated by the signal processing circuit and generates a CAPA signal including a binarized signal;
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the CAPA detection signal output from the signal processing circuit, and a peak / bottom difference signal [Spek−Sbtm] is generated. The optical disk apparatus is characterized in that it generates a CAPA signal by executing a binarization process based on a threshold value.

  Furthermore, in one embodiment of the optical disc apparatus of the present invention, the signal processing circuit inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disc reproduction signal, and adds the signal (A + D). And a DC cut signal for the addition signal (B + C), and a push-pull signal [(A + D) − (B + C)] as a differential signal based on the DC cut signal, and the CAPA detection circuit A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)], and the peak / bottom difference signal [Spek] is generated. -Sbtm] threshold value is generated, and a CAPA signal is generated by performing binarization processing. .

  Furthermore, in an embodiment of the optical disk device of the present invention, the CAPA detection circuit includes an offset adjustment circuit that executes a threshold generation process for executing a binarization process of the peak-bottom difference signal [Spek-Sbtm]; It is characterized by having a comparator that generates a CAPA signal composed of a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit.

  Furthermore, in an embodiment of the optical disc apparatus of the present invention, the CAPA detection circuit receives the peak-bottom difference signal [Spek-Sbtm] and the output of the low-pass filter and inputs the peak-bottom difference signal. Comparing processing of offset adjustment circuit for executing threshold generation processing for executing binarization processing of [Spek-Sbtm], peak-to-bottom difference signal [Spek-Sbtm], and threshold generated by offset adjustment circuit And a comparator that generates a CAPA signal composed of a binarized signal.

  Furthermore, in one embodiment of the optical disc apparatus of the present invention, the signal processing circuit inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disc reproduction signal, and adds the signal (A + D). And a DC cut signal for the addition signal (B + C), a push-pull signal [(A + D) − (B + C)] as a differential signal based on the DC cut signal is generated, and the push-pull signal [(A + D) − ( B + C)], and the CAPA detection circuit generates the digital signal based on the push-pull signal [(A + D) − (B + C)] as an output of the AD converter. Peak bottom difference signal [Sp] obtained by subtracting bottom level hold signal [Sbtm] from peak level hold signal [Speak] k-SBTM] generates, characterized in that it is configured to generate a CAPA signal by performing a binarization process by a threshold value of the peak-bottom differential signal [Spek-Sbtm].

Furthermore, the second aspect of the present invention provides
A signal processing device for performing signal processing;
A signal processing circuit for performing a wobble signal detection process of a data track recorded on an optical disc and generating a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc;
A CAPA detection circuit that inputs a CAPA detection signal generated by the signal processing circuit and generates a CAPA signal including a binarized signal;
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the CAPA detection signal output from the signal processing circuit, and a peak / bottom difference signal [Spek−Sbtm] is generated. The signal processing apparatus is characterized in that it generates a CAPA signal by executing a binarization process based on the threshold value.

  Furthermore, in one embodiment of the signal processing apparatus of the present invention, the signal processing circuit inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal, and adds the signal (A + D). ) And the addition signal (B + C), and a push-pull signal [(A + D) − (B + C)] as a difference signal based on the DC cut signal is generated. The CAPA detection circuit includes: A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)]. It is configured to generate a CAPA signal by executing binarization processing using a threshold of [Spek-Sbtm]

  Furthermore, in one embodiment of the signal processing apparatus of the present invention, the CAPA detection circuit includes an offset adjustment circuit that executes a threshold generation process for executing a binarization process of the peak-bottom difference signal [Spek-Sbtm]. And a comparator that generates a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit. .

  Furthermore, in one embodiment of the signal processing apparatus of the present invention, the CAPA detection circuit includes a low-pass filter that inputs the peak-bottom difference signal [Spek−Sbtm], and an output of the low-pass filter that inputs the peak-bottom difference. Comparison of an offset adjustment circuit that executes threshold generation processing for executing binarization processing of the signal [Spek-Sbtm], the peak-bottom difference signal [Spek-Sbtm], and a threshold generated by the offset adjustment circuit And a comparator that generates a CAPA signal including a binarized signal by processing.

  Furthermore, in one embodiment of the signal processing apparatus of the present invention, the signal processing circuit inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal, and adds the signal (A + D). ) And the added signal (B + C), a push-pull signal [(A + D) − (B + C)] as a differential signal based on the DC cut signal is generated, and the push-pull signal [(A + D) − An AD converter that generates a digital signal based on (B + C)], and the CAPA detection circuit generates the digital signal based on the push-pull signal [(A + D) − (B + C)] as an output of the AD converter. The peak bottom difference signal [Spe] obtained by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak] thus obtained. Generates -Sbtm], characterized in that it is configured to generate a CAPA signal by performing a binarization process by a threshold value of the peak-bottom differential signal [Spek-Sbtm].

Furthermore, the third aspect of the present invention provides
A signal processing method in an optical disc apparatus for executing data recording or reproduction processing using an optical disc,
The signal processing circuit executes a wobble signal detection process of the data track recorded on the disc and generates a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc. A signal processing step;
The CAPA detection circuit has a CAPA signal generation step for inputting a CAPA detection signal generated in the signal processing step and generating a CAPA signal composed of a binarized signal.
The CAPA signal generation step includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the CAPA detection signal output in the signal processing step, and a peak / bottom difference signal [Spek− The signal processing method is characterized in that it is a step of generating a CAPA signal by executing a binarization process using a threshold value of [Sbtm].

  Furthermore, in one embodiment of the signal processing method of the present invention, the signal processing step inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal, and adds the signal (A + D). ) And the addition signal (B + C), and a push-pull signal [(A + D) − (B + C)] as a differential signal based on the DC cut signal is generated. The CAPA signal generation step includes: The peak-bottom difference signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)]. In a step of generating a CAPA signal by executing a binarization process using a threshold of [Spek-Sbtm] And wherein the Rukoto.

  Furthermore, in one embodiment of the signal processing method of the present invention, the CAPA signal generation step performs threshold generation processing for executing binarization processing of the peak-bottom difference signal [Spek-Sbtm] in an offset adjustment circuit. An offset adjustment step, and a step of generating a CAPA signal composed of a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit. To do.

  Furthermore, in one embodiment of the signal processing method of the present invention, the CAPA signal generation step includes the step of inputting the peak-bottom difference signal [Spek-Sbtm] into a low-pass filter, and the output of the low-pass filter as input. Offset adjustment step for executing threshold generation processing for executing binarization processing of the peak-bottom difference signal [Spek-Sbtm] in the offset adjustment circuit, the peak-bottom difference signal [Spek-Sbtm], and the offset adjustment circuit The method includes a step of generating a CAPA signal including a binarized signal by a comparison process with a threshold value generated by.

  Furthermore, in one embodiment of the signal processing method of the present invention, the signal processing step inputs each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal, and adds the signal (A + D). ) And the added signal (B + C), a push-pull signal [(A + D) − (B + C)] as a differential signal based on the DC cut signal is generated, and the push-pull signal [(A + D) − (B + C)] based on the digital signal of the push-pull signal [(A + D) − (B + C)]. The peak level hold signal [Speak] is generated. ] To generate a peak / bottom difference signal [Spek−Sbtm] obtained by subtracting the bottom level hold signal [Sbtm]. Characterized in that it is a step of generating a CAPA signal by performing a binarization process by a threshold value of Kubotomu difference signal [Spek-Sbtm].

  Other objects, features, and advantages of the present invention will become apparent from a more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  According to the configuration of an embodiment of the present invention, a processing circuit for detecting CAPA (Complementary Allocated Pit Addressing) as address information recorded on a disc and a processing circuit for wobble signal detection processing are commonly used. This makes it possible to reduce the size and cost of the apparatus. According to the configuration of one embodiment of the present invention, a CAPA detection circuit receives a DC cut push-pull signal generated by a processing circuit for CAPA detection and a common signal processing circuit for wobble signal detection processing. Thus, a peak / bottom difference signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak], and binarization processing is performed using the threshold value of the peak / bottom difference signal [Spek−Sbtm]. Since the configuration is such that the CAPA signal is generated by execution, accurate control can be realized by generating the CAPA signal without any problem even when waveform distortion due to DC cut occurs.

  The details of the optical disc apparatus, signal processing apparatus, and signal processing method of the present invention will be described below with reference to the drawings.

  FIG. 6 is a diagram showing an example of a processing circuit in which the wobble detection circuit and the CAPA detection circuit in the disk apparatus of the present invention are made common to realize downsizing and low cost. When the method according to the present invention described below is used, CAPA detection can be performed even with a DC-cut push-pull signal. Therefore, as described above with reference to FIG. 3, a wobble detection circuit and a CAPA detection signal generation circuit are provided. Are separately provided, that is, an independent dedicated circuit for generating a CAPA detection signal, which has been conventionally required, becomes unnecessary.

  Also in the disk apparatus according to the embodiment of the present invention described below, the optical pickup is an RF signal by the optical sensor divided into the areas A, B, C, and D described above with reference to FIG. A configuration for acquiring (A, B, C, D) is used. That is, the A and D sides of the four divided sensor areas A, B, C, and D shown in FIG. 2 are the CAPA 111 area side of the header field shown in FIG. 1, and the B and C sides are the header fields shown in FIG. A setting corresponding to the area side of the CAPA 112 is set, and a push-pull signal [(A + D) − (B + C)] is generated in the signal processing circuit of the disk device, and a deviation amount from the track center is calculated based on a change in this signal. The pickup is then controlled by the track center.

  As shown in FIG. 6, the signal processing circuit according to the present invention can set a wobble signal processing circuit and a CAPA detection signal generation circuit as a common circuit. Processing of the signal processing circuit shown in FIG. 6 will be described.

  The RF signals (A, B, C, D) input to the wobble signal processing circuit 300 are added by the adder circuits 301 and 302, respectively, and a signal (A + D) and a signal (B + C) are generated. These signals (A + D) and (B + C) are subtracted after the DC components are cut by high-pass filters (HPF) 303 and 304 and further adjusted to appropriate amplitudes by gain control amplifiers (GCAs) 305 and 306. A push-pull signal [(A + D) − (B + C)] is generated by the circuit 307. As a result, the RF signal is canceled because it is in phase, and a reverse-phase wobble signal and a CAPA detection signal remain.

  The push-pull signal [(A + D) − (B + C)] has its DC component cut by a high-pass filter (HPF) 308 and is adjusted to an appropriate amplitude by a gain control amplifier (GCA) 309. The output of the gain control amplifier (GCA) 309 is divided into a wobble signal detection signal and a CAPA signal detection signal.

  A wobble signal detection signal is input from a gain control amplifier (GCA) 309 to a bandpass filter (BPF) 310. The band pass filter (BPF) 310 extracts only the signal component of the wobble band from the input signal, and inputs the extracted signal to the comparator (Comp) 311. The comparator (Comp) 311 executes a binarization process with a predetermined threshold value, generates a binarization pulse, and outputs it to the PLL. In the PLL, control is executed by generating a signal for controlling the disk rotation speed, for example, in accordance with the input binary pulse.

  The CAPA detection signal constituted by the output of the gain control amplifier (GCA) 309 is input to the CAPA detection circuit 321, and a CAPA signal is generated by the CAPA detection method according to the present invention.

  FIG. 7 shows a detailed configuration example of the CAPA detection circuit 321 that executes the CAPA detection method according to the present invention. FIG. 7 is a block diagram showing a detailed configuration of the CAPA detection circuit 321 according to an embodiment of the present invention, and FIG. 8 is a waveform diagram for explaining processing of the CAPA detection circuit 321 shown in FIG.

  As shown in FIG. 7, the CAPA detection circuit 321 includes a peak hold circuit 401, a bottom hold circuit 402, a subtraction circuit 403 that subtracts the bottom hold signal from the peak hold signal, an offset adjustment circuit 404, and a comparator 405.

  The CAPA detection circuit 321 inputs a CAPA detection signal that is an output of the gain control amplifier (GCA) 309 of the wobble signal processing circuit 300 shown in FIG. 7, that is, a push-pull signal. The peak hold circuit 401 outputs a signal [Speak] obtained by holding the peak level of the input push-pull signal. FIG. 8A shows a peak level hold signal [Speak] 451 obtained by holding the peak level of the push-pull signal.

  On the other hand, the bottom hold circuit 402 outputs a signal [Sbtm] obtained by holding the bottom level of the push-pull signal. 8A is a bottom level hold signal [Sbtm] 452 obtained by holding the bottom level of the push-pull signal.

  The subtraction circuit 403 outputs a peak / bottom difference signal [Spek−Sbtm] obtained by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak]. This is the peak-bottom differential signal [Spek−Sbtm] 453 shown in FIG.

  The comparator 405 outputs the CAPA signal by binarizing the peak-bottom difference signal [Spek−Sbtm] with the threshold value [Sref] adjusted by the offset adjustment circuit 404 with reference to 0V.

  That is, the peak-bottom difference signal [Spek−Sbtm] 453 shown in FIG. 8B is compared with the threshold value [Sref] 454, and the binarized CAPA signal shown in FIG.

  Note that the binarized CAPA signal shown in FIG. 8C is one pulse for the header field 110 shown in FIG. On the other hand, in the conventional configuration described with reference to FIG. 5, two pulses are used as the high-level CAPA signal, the pulse for CAPA 111 shown in FIG. 1, and the low-level CAPA signal as the pulse for CAPA 112 shown in FIG. . The CAPA detection circuit 321 of the present invention is configured to generate only one pulse for the header field 110 shown in FIG. 1, but even in this one-pulse configuration, the pickup is deviated from the center. In this case, a change occurs in the pulse width, and it is possible to determine the deviation from the center, and control based on this one-pulse CAPA signal is executed.

  The threshold value [Sref] may be based on 0V in principle. However, if the circuit offset cannot be ignored, as shown in FIG. 9, the peak-bottom differential signal [Spek-Sbtm] is passed through the low-pass filter (LPF) 481 and the output from which the high-frequency component is removed is offset using the reference signal. A configuration may be adopted in which the threshold value [SLref] is generated based on the reference signal by inputting to the adjustment circuit 404 and in the offset adjustment circuit 404.

  In the case of this configuration, the comparator 405 sets the threshold value [SLref] generated by the adjustment in the offset adjustment circuit 404 with respect to the peak-bottom difference signal [Spek−Sbtm] based on the output passed through the low-pass filter (LPF) 481. A CAPA signal is output by performing binarization based on the comparison processing based on the above.

  Note that the period of each wobble signal is 186 times that of the RF signal and that of the CAPA signal is four times that of the RF signal, so there is a difference in the period of each signal, so the peak hold circuit 401 of the CAPA detection circuit 321 shown in FIG. By adjusting the time constant of the bottom hold circuit 402 to match the period of the CAPA signal, it is possible to extract a signal that selectively holds only the CAPA signal without holding the wobble signal. .

  As described above, in the configuration of the present invention, the CAPA detection circuit 321 inputs the output of the gain control amplifier (GCA) 309 as the CAPA detection signal using the common circuit with the wobble signal processing circuit 300 shown in FIG. Then, the peak level hold signal [Speak] and the bottom level hold signal [Sbtm] are generated, and the peak level difference signal [Spek−, which is obtained by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak]. Sbtm] is generated, and the peak-bottom difference signal [Spek-Sbtm] is binarized by a threshold value, whereby the high-quality CAPA signal shown in FIG. 8C can be output.

  The wobble signal processing circuit 300 shown in FIG. 7 performs DC component cut processing in the high-pass filters (HPFs) 303 and 304 in order to generate a signal for wobble signal detection processing as in the conventional case. The push-pull signal input to the CAPA detection circuit 321 has the same waveform as that shown in FIG. 8A, that is, the waveform described above with reference to FIG. The CAPA detection circuit 321 of the invention generates a peak / bottom difference signal [Spek−Sbtm] obtained by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak], and generates the peak / bottom difference signal [Spek−Sbtm]. By configuring the binarization process using the threshold, the high-quality CAPA signal shown in FIG. 8C is output. Rukoto can.

  According to the configuration of the present invention, as shown in FIG. 8, the peak-bottom difference signal [Spek-Sbtm] generated from the push-pull signal that is the CAPA detection signal becomes a signal distorted by DC cut. Even for a signal having a peak value, only the amplitude component of the CAPA detection signal is extracted by generating the peak-bottom difference signal [Spek-Sbtm], and a threshold value for this amplitude component (peak-bottom difference signal [Spek-Sbtm]) is extracted. By adopting a configuration for performing binarization processing to which (Sref) is applied, a high-quality CAPA signal shown in FIG. 8C can be output.

  In the configuration of the wobble signal processing circuit 300 shown in FIG. 6, the signal input to the CAPA detection circuit 321 is an analog signal. However, as shown in the wobble signal processing circuit 500 shown in FIG. 10, a gain control amplifier (GCA) The output of 309 is input to an anti-aliasing filter (AAF) 501 to remove high-frequency components, converted into digital data by an AD converter (A / D) 502, and wobbled from the digital data by a band-pass filter (BPF) 503. ) Only the band signal component may be extracted. In this configuration, the CAPA detection signal becomes a digital signal of the AD converter (A / D) 502, and the CAPA detection circuit 521 inputs the push-pull signal as a digital signal and performs CAPA by digital signal processing. Generate a signal.

  The CAPA detection circuit 521 generates a peak level hold signal [Speak] and a bottom level hold signal [Sbtm] from a digitalized push-pull signal, and generates a bottom level from the peak level hold signal [Speak]. A digital bottom level signal [Spek-Sbtm] obtained by subtracting the level hold signal [Sbtm] is generated, and the peak / bottom difference signal [Spek-Sbtm] is binarized using a threshold value. As a result, the high-quality CAPA signal shown in FIG. 8C can be output.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present invention. In other words, the present invention has been disclosed in the form of exemplification, and should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims should be taken into consideration.

  Note that the various processes described in the specification are not only executed in time series according to the description, but may be executed in parallel or individually according to the processing capability of the apparatus that executes the processes or as necessary.

  As described above, according to the configuration of the embodiment of the present invention, the processing circuit for detecting CAPA (Complementary Allocated Pit Addressing) as address information recorded on the disc, and the wobble signal detection process Many of the processing circuits can be made common, and the apparatus can be reduced in size and cost. According to the configuration of one embodiment of the present invention, a CAPA detection circuit receives a DC cut push-pull signal generated by a processing circuit for CAPA detection and a common signal processing circuit for wobble signal detection processing. Thus, a peak / bottom difference signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak], and binarization processing is performed using the threshold value of the peak / bottom difference signal [Spek−Sbtm]. Since the configuration is such that the CAPA signal is generated by execution, accurate control can be realized by generating the CAPA signal without any problem even when waveform distortion due to DC cut occurs.

It is a figure explaining a CAPA (Complementary Allocated Pit Addressing) detection process. It is a figure which shows the detailed structural example of the optical pick-up in an optical disk device. It is a figure which shows the general structure of the wobble (Wobble) signal processing circuit and CAPA detection signal generation circuit in the signal processing circuit of an optical disk apparatus. It is a figure explaining the example of a circuit which inputs the push pull signal [(A + D)-(B + C)], and outputs the binarized high level CAPA signal and the binarized low level CAPA signal. When a push-pull signal [(A + D) − (B + C)] as shown in FIG. 4 is input and a signal processing configuration is used to output a binarized high level CAPA signal and a binarized low level CAPA signal. It is a figure explaining the signal waveform of. It is a figure explaining the structure and process of the signal processing circuit which concerns on one Example of this invention. It is a figure explaining the structure and process of one Example of the CAPA detection circuit which is a signal processing circuit based on one Example of this invention. It is a figure explaining the process performed in the signal processing structure of the CAPA detection circuit shown in FIG. It is a figure explaining the structure and process of one Example of the CAPA detection circuit which is a signal processing circuit based on one Example of this invention. It is a figure explaining the structure and process of the signal processing circuit which concerns on one Example of this invention.

Explanation of symbols

101 track 102 light spot 111 header field 111, 112 CAPA (Complementary Allocated Pit Addressing)
151 Optical disk 152 Objective lens 153 Half prism 154 Collimator lens 155 Laser 156 Optical sensor 157 Optical pickup 170 Wobble signal processing circuit 171, 172 Adder circuit 173, 174 High pass filter (HPF)
175, 176 Gain control amplifier (GCA)
177 Subtraction circuit 178 High pass filter (HPF)
179 Gain control amplifier (GCA)
180 Band pass filter (BPF)
181 Comparator (Comp)
190 CAPA detection signal generation circuit 191, 192 Addition circuit 193, 194 Gain control amplifier (GCA)
195 Subtraction circuit 196 Gain control amplifier (GCA)
197 CAPA detection circuit 201 Peak hold circuit 202 Bottom hold circuit 203, 204 Comparator 300 Wobble signal processing circuit 301, 302 Adder circuit 303, 304 High pass filter (HPF)
305,306 Gain control amplifier (GCA)
307 Subtraction circuit 308 High-pass filter (HPF)
309 Gain control amplifier (GCA)
310 Band pass filter (BPF)
311 Comparator (Comp)
321 CAPA detection signal generation circuit 401 Peak hold circuit 402 Bottom hold circuit 403 Subtraction circuit 404 Offset adjustment circuit 405 Comparator 451 Peak level hold signal [Speak]
452 Bottom level hold signal [Sbtm]
453 Peak-bottom differential signal [Spek-Sbtm]
454 Threshold [Sref]
481 Low-pass filter (LPF)
501 Anti-aliasing filter (AAF)
502 AD converter (A / D)
521 CAPA detection circuit

Claims (15)

An optical disc apparatus that executes data recording or reproduction processing using an optical disc,
A signal processing circuit for performing a wobble signal detection process of a data track recorded on the disc and generating a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc;
A CAPA detection circuit that inputs a CAPA detection signal generated by the signal processing circuit and generates a CAPA signal including a binarized signal;
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the CAPA detection signal output from the signal processing circuit, and a peak / bottom difference signal [Spek−Sbtm] is generated. An optical disc apparatus that generates a CAPA signal by performing binarization processing using a threshold value of The signal processing circuit includes:
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. A configuration for generating a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon,
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)]. 2. The optical disc apparatus according to claim 1, wherein the optical disc apparatus is configured to generate a CAPA signal by performing binarization processing using a threshold of (Spek-Sbtm). The CAPA detection circuit includes:
An offset adjustment circuit that executes threshold generation processing for executing binarization processing of the peak-bottom difference signal [Spek-Sbtm];
A comparator that generates a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit;
The optical disk apparatus according to claim 1, wherein the optical disk apparatus has a configuration including: The CAPA detection circuit includes:
A low-pass filter for inputting the peak-bottom differential signal [Spek-Sbtm];
An offset adjustment circuit for performing threshold generation processing for performing binarization processing of the peak-bottom difference signal [Spek-Sbtm] by inputting the output of the low-pass filter;
A comparator that generates a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit;
The optical disk apparatus according to claim 1, wherein the optical disk apparatus has a configuration including: The signal processing circuit includes:
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. An AD converter that generates a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon and generates a digital signal based on the push-pull signal [(A + D) − (B + C)],
The CAPA detection circuit includes:
A peak / bottom difference signal obtained by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] generated based on the digital signal of the push-pull signal [(A + D) − (B + C)] as an output of the AD converter. 2. The optical disc apparatus according to claim 1, wherein [Spek-Sbtm] is generated, and binarization processing is performed by using a threshold value of the peak-bottom difference signal [Spek-Sbtm] to generate a CAPA signal. . A signal processing device for performing signal processing;
A signal processing circuit for performing a wobble signal detection process of a data track recorded on an optical disc and generating a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc;
A CAPA detection circuit that inputs a CAPA detection signal generated by the signal processing circuit and generates a CAPA signal including a binarized signal;
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the CAPA detection signal output from the signal processing circuit, and a peak / bottom difference signal [Spek−Sbtm] is generated. A signal processing apparatus characterized in that it generates a CAPA signal by performing binarization processing using a threshold value of The signal processing circuit includes:
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. A configuration for generating a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon,
The CAPA detection circuit includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)]. The signal processing apparatus according to claim 6, wherein the signal processing apparatus is configured to generate a CAPA signal by performing binarization processing using a threshold of (Spek−Sbtm). The CAPA detection circuit includes:
An offset adjustment circuit that executes threshold generation processing for executing binarization processing of the peak-bottom difference signal [Spek-Sbtm];
A comparator that generates a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit;
The signal processing apparatus according to claim 6, wherein the signal processing apparatus has a configuration. The CAPA detection circuit includes:
A low-pass filter for inputting the peak-bottom differential signal [Spek-Sbtm];
An offset adjustment circuit for performing threshold generation processing for performing binarization processing of the peak-bottom difference signal [Spek-Sbtm] by inputting the output of the low-pass filter;
A comparator that generates a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit;
The signal processing apparatus according to claim 6, wherein the signal processing apparatus has a configuration. The signal processing circuit includes:
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. An AD converter that generates a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon and generates a digital signal based on the push-pull signal [(A + D) − (B + C)],
The CAPA detection circuit includes:
A peak / bottom difference signal obtained by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] generated based on the digital signal of the push-pull signal [(A + D) − (B + C)] as an output of the AD converter. The signal processing according to claim 6, wherein [Spek−Sbtm] is generated, and binarization processing is executed using a threshold value of the peak / bottom difference signal [Spek−Sbtm] to generate a CAPA signal. apparatus. A signal processing method in an optical disc apparatus for executing data recording or reproduction processing using an optical disc,
The signal processing circuit executes a wobble signal detection process of the data track recorded on the disc and generates a CAPA detection signal based on CAPA (Complementary Allocated Pit Addressing) information as address information recorded on the disc. A signal processing step;
The CAPA detection circuit has a CAPA signal generation step for inputting a CAPA detection signal generated in the signal processing step and generating a CAPA signal composed of a binarized signal,
The CAPA signal generation step includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak] of the CAPA detection signal output in the signal processing step, and the peak / bottom difference signal [Spe− A signal processing method, which is a step of generating a CAPA signal by performing binarization processing using a threshold value of Sbtm]. The signal processing step includes
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. Generating a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon,
The CAPA signal generation step includes:
A peak / bottom difference signal [Spek−Sbtm] is generated by subtracting a bottom level hold signal [Sbtm] from a peak level hold signal [Speak] of the push-pull signal [(A + D) − (B + C)]. 12. The signal processing method according to claim 11, wherein the signal processing method is a step of generating a CAPA signal by performing binarization processing using a threshold of (Spek-Sbtm). The CAPA signal generation step includes:
An offset adjustment step in which an offset adjustment circuit executes threshold generation processing for executing binarization processing of the peak-bottom difference signal [Spek-Sbtm];
12. The method according to claim 11, further comprising: generating a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek-Sbtm] with a threshold generated by the offset adjustment circuit. Signal processing method. The CAPA signal generation step includes:
Inputting the peak-bottom difference signal [Spek-Sbtm] to a low-pass filter;
An offset adjustment step in which an offset adjustment circuit executes threshold generation processing for inputting the output of the low-pass filter and executing binarization processing of the peak-bottom difference signal [Spek-Sbtm];
12. The method according to claim 11, further comprising: generating a CAPA signal including a binarized signal by comparing the peak-bottom difference signal [Spek−Sbtm] with a threshold value generated by the offset adjustment circuit. Signal processing method. The signal processing step includes
Each area signal (A, B, C, D) of the quadrant sensor obtained as an optical disk reproduction signal is input, a DC cut signal for the addition signal (A + D) and the addition signal (B + C) is generated, and the DC cut signal is generated. Generating a push-pull signal [(A + D) − (B + C)] as a difference signal based thereon, and generating a digital signal based on the push-pull signal [(A + D) − (B + C)],
The CAPA signal generation step includes:
A peak / bottom differential signal [Spek−Sbtm] is generated by subtracting the bottom level hold signal [Sbtm] from the peak level hold signal [Speak] generated based on the digital signal of the push-pull signal [(A + D) − (B + C)]. The signal processing method according to claim 11, wherein the signal processing method is a step of generating a CAPA signal by performing binarization processing using a threshold value of the peak-bottom differential signal [Spek−Sbtm].

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