JP2010231869A - Disturbance noise discriminating device, disturbance noise discriminating method, and disturbance-noise discriminating program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disturbance-noise discriminating device by which disturbance noise of a servo loop can be detected accurately, without providing a current-detecting circuit. <P>SOLUTION: A disturbance-noise discriminating device includes a standard reference signal generating means for generating a standard reference signal of a prescribed frequency; an adding means for adding the standard reference signal to an error signal in a servo loop; a filter means for making the prescribed frequency component of the error signal pass through it; a phase difference detecting means for detecting the phase difference between a phase of the standard reference signal and a phase of the error signal which has passed through the filter means; a phase control means for stepwise changing the phase of the error signal passing through the filter means, by changing stepwise a setting phase value of the filter means; and a disturbance-noise discriminating means for discriminating that a disturbance noise exists, when change quantity of a value corresponding to the phase difference detected a plurality of times by the phase difference detecting means, in a process in which the setting phase value of the filter means is changed in a stepwise manner. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technical field such as a disturbance noise determination apparatus that determines the presence or absence of disturbance noise in a servo loop of an apparatus capable of reading information from an information recording medium such as an optical disk.

  2. Description of the Related Art Conventionally, for example, in an optical disc recording / reproducing apparatus, a technique for adjusting a gain of a servo loop is known in order to perform stable servo control. However, for example, when a disturbance noise having a high frequency component with respect to the servo band is applied to the servo loop during an optical disc playback operation, the servo suppression control does not work, resulting in an increase in current components and thermal components. It was.

  As a means for solving such a problem, a method is known in which a current detection circuit is provided, and when a current of a predetermined value or more is detected, the gain adjustment is stopped or the reproduction operation is stopped. However, in the case of this method, it is necessary to connect a low resistance to the series as a current detection circuit with respect to the load, and there is a problem that affects the servo operation such as a narrow operating range. Further, there is a method of detecting the drive voltage and calculating the current from the load resistance, but there is a drawback that the accuracy is poor when the variation of the load resistance is large.

  For example, Japanese Patent Application Laid-Open No. 5-173641 proposes a technique for determining that an abnormal state is detected when saturation of a signal in a servo loop is detected and interrupting gain adjustment.

Japanese Patent Laid-Open No. 5-173641

  However, in the method of detecting the saturation of the signal in the servo loop, it is necessary to capture the amplitude information of the signal into, for example, a microcomputer, but there is a limit because the accuracy of the amplitude information is not high. In order to obtain highly accurate amplitude information, although a current detection circuit is required, there are problems as described above.

  Therefore, the present application has been made in view of the above points, and an example of the problem is a disturbance noise determination device and a disturbance noise determination that can accurately detect disturbance noise without providing a current detection circuit. A method and a disturbance noise determination program are provided.

  In order to solve the above-mentioned problem, the invention described in claim 1 is a disturbance noise determination apparatus for determining the presence or absence of disturbance noise in a servo loop of an apparatus capable of reading information from an information recording medium, wherein a reference of a predetermined frequency is referred to A reference reference signal generating means for generating a signal, an adding means for adding the reference reference signal to an error signal in the servo loop, a filter means for passing the predetermined frequency component of the error signal in the servo loop, and the reference reference signal The phase difference detecting means for detecting the phase difference between the phase of the error signal and the phase of the error signal that has passed through the filter means, and the error passing through the filter means by changing the set phase value of the filter means stepwise. Phase control means for changing the phase of the signal stepwise, and a process for changing the set phase value of the filter means stepwise And a disturbance noise determination unit that determines that the disturbance noise is present when a change amount of a value corresponding to the phase difference detected a plurality of times by the phase difference detection unit becomes a predetermined amount or less. It is characterized by.

  The invention according to claim 3 is a disturbance noise determination method for determining the presence or absence of disturbance noise in a servo loop of an apparatus capable of reading information from an information recording medium, the step of generating a reference reference signal of a predetermined frequency, A step of adding the reference signal to the error signal in the servo loop; a phase difference between the position of the error signal that has passed through the filter means that passes the predetermined frequency component of the error signal in the servo loop; and the phase of the reference signal A step of changing the phase of the error signal passing through the filter means stepwise by changing the set phase value of the filter means stepwise, and the setting phase value of the filter means When the amount of change in the value corresponding to the phase difference detected multiple times in the process of stepwise change is below a predetermined amount, Kigairan noise, characterized in that it and a step of determining a chromatic.

  The invention of a disturbance noise determination program according to claim 4 is a computer for determining the presence or absence of disturbance noise in a servo loop of a device capable of reading information from an information recording medium, and generating a reference reference signal having a predetermined frequency. Signal generating means; adding means for adding the reference signal to the error signal in the servo loop; filter means for passing the predetermined frequency component of the error signal in the servo loop; phase of the reference signal and the filter means A phase difference detecting means for detecting a phase difference from the phase of the error signal that has passed through the filter means, by changing the set phase value of the filter means stepwise, the error signal passing through the filter means The phase control means for changing the phase of the filter stepwise, and the set phase value of the filter means Disturbance noise determination means for determining that the disturbance noise is present when a change amount of a value corresponding to the phase difference detected by the phase difference detection means a plurality of times in the process of being changed is equal to or less than a predetermined amount It is made to function as.

It is a figure which shows an example of schematic structure of the optical disk recording / reproducing apparatus which concerns on this embodiment. It is a figure which shows an example of the relationship (phase characteristic) of the phase difference detected by the phase comparator 10, and the gain in a servo loop, when there is no disturbance noise. It is a figure which shows an example of the relationship (phase characteristic) of the phase difference detected by the phase comparator 10, and the gain in a servo loop, when there exists disturbance noise. It is a figure which shows an example of the input-output waveform of the phase comparator 10 using an EXOR circuit. It is a figure which shows an example of the input-output phase characteristic of the phase comparator 10 using an EXOR circuit. It is a figure which shows an example of the relationship between the phase difference detected by the phase comparator 10 when a BPF characteristic is changed, and the gain in a servo loop when there is disturbance noise. It is a figure which shows the phase characteristic when BPF characteristic is changed. It is a figure which shows an example of the input-output waveform of the phase comparator 10 in the process in which the phase of the error signal which passes the band pass filter 9 is changed in steps. 6 is a flowchart illustrating an example of disturbance noise determination processing in the microcomputer 16 in the first embodiment. FIG. 6 is a diagram illustrating an example of a relationship between a phase difference detected by a phase comparator and a gain in a servo loop in disturbance noise determination processing according to the first embodiment. 6 is a diagram illustrating a relationship between a phase difference detected by a phase comparator 10 and a set phase value in a bandpass filter 9 in Embodiment 1. FIG. 10 is a flowchart illustrating an example of disturbance noise determination processing in the microcomputer 16 in the second embodiment. In Example 2, it is a figure which shows the relationship between the phase difference detected by the phase comparator, and the setting phase value in the band pass filter.

  Hereinafter, embodiments of the present application will be described in detail with reference to the drawings. The embodiment described below is an embodiment when the present application is applied to an optical disc recording / reproducing apparatus such as a CD (Compact Disc), a DVD (Digital Versatile Disc), a BD (Blu-ray Disc), and an HDDVD. It is.

  First, the configuration and function of the optical disc recording / reproducing apparatus according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a diagram showing an example of a schematic configuration of an optical disc recording / reproducing apparatus according to the present embodiment. As shown in FIG. 1, an optical disc recording / reproducing apparatus S includes a driver 1, a spindle motor 2, an optical pickup 3, an RF amplifier 4, a gain variable amplifier 5, an adder 6 (an example of adding means), a phase compensation equalizer 7, and an oscillator. 8 (an example of a standard reference signal generation unit), a bandpass filter (BPF) 9 (an example of a filter unit), a phase comparator 10 (an example of a phase difference detection unit), a gain determination window 11, an audio / video signal processing memory control 12, a memory 13, a DAC (digital / analog converter) 14, a display control unit 15, a microcomputer 16, and the like. The driver 1, the optical pickup 3, the RF amplifier 4, the gain variable amplifier 5, the adder 6, and the phase compensation equalizer 7 constitute a servo loop in servo control. The microcomputer 16 functions as a phase control unit and a disturbance noise determination unit by performing overall control of the above-described units and executing a disturbance noise determination program stored in the internal memory.

  The driver 1 drives and controls the spindle motor 2 and the optical pickup 3 according to the drive signal from the phase compensation equalizer 7. The optical pickup 3 irradiates a rotating optical disk D with a light beam, reads recorded information from the optical disk D, and supplies the read signal to the RF amplifier 4.

  The RF amplifier 4 amplifies the read signal from the optical pickup 3 and then supplies it to the audio / video signal processing memory control 12 and extracts error signals such as a tracking error signal and a focus error signal based on the read signal. This is supplied to the variable gain amplifier 5 and the band pass filter 9.

  The audio / video signal processing memory control 12 uses the memory 13 to perform demodulation and error correction of the read signal from the RF amplifier 4 to generate an audio signal and a video signal, and supply the audio signal to the DAC 14. The video signal is supplied to the display control unit 15. The DAC 14 converts an audio signal (digital signal) from the audio / video signal processing memory control 12 into an analog signal and outputs the analog signal to a speaker through an amplifier (not shown). Further, the display control unit 15 performs drawing processing on the video signal from the audio / video signal processing memory control 12 and outputs it to a display (not shown).

  On the other hand, the variable gain amplifier 5 adjusts the gain (gain) of the servo loop in accordance with the gain adjustment command from the gain determination window 11.

  The oscillator 8 generates a sine wave standard reference signal (also referred to as a disturbance signal) having a predetermined frequency, and supplies the standard reference signal to the adder 6 and the phase comparator 10. The adder 6 adds the error signal from the gain variable amplifier 5 and the standard reference signal from the oscillator 8, that is, adds the standard reference signal to the error signal in the servo loop and supplies it to the phase compensation equalizer 7. The phase compensation equalizer 7 adjusts the phase of the signal from the adder 6 and supplies it to the driver 1 as a drive signal.

  The band-pass filter 9 passes a predetermined frequency (same frequency as the reference signal) component of the error signal, which is an error signal to which the reference signal is added by the adder 6 and has made a round of the servo loop, to pass through the phase comparator. 10 is supplied.

  The phase comparator 10 includes, for example, an EXOR circuit, and compares the phase of the standard reference signal from the oscillator 8 with the phase of the error signal that has passed through the bandpass filter 9 (that is, the signal that the standard reference signal has made a round of the servo loop). Then, those phase differences are detected and supplied to the gain determination window 11 and the microcomputer 16. The gain determination window 11 gives a gain adjustment command to the variable gain amplifier 5 based on the difference between the phase difference detected by the phase comparator 10 and a preset target phase value. More specifically, the gain determination window 11 gives a gain adjustment command indicating a gain change amount (dB) according to the difference between the phase difference and the target phase value to the gain variable amplifier 5. As a result, the gain variable amplifier 5 performs gain adjustment (increase or decrease) by the gain change amount (dB) indicated in the gain adjustment command.

  Here, the relationship between the phase difference detected by the phase comparator 10 and the gain in the servo loop will be described.

  FIG. 2 is a diagram showing an example of the relationship (phase characteristic) between the phase difference detected by the phase comparator 10 and the gain in the servo loop in the absence of disturbance noise, and FIG. 3 shows the presence of disturbance noise. In the case, it is a figure which shows an example of the relationship (phase characteristic) of the phase difference detected by the phase comparator 10 and the gain in a servo loop.

  As shown in FIG. 2, when there is no disturbance noise, the gain is set based on the phase difference detected by the phase comparator -90 deg (that is, the error signal is delayed by 90 degrees from the reference signal). On the other hand, the linear characteristic changes linearly in the direction in which the phase difference increases and decreases.

  On the other hand, as shown in FIG. 3, when there is disturbance noise, that is, when disturbance noise is applied to the servo loop, the phase difference increases with reference to the phase difference of −90 deg detected by the phase comparator 10. The saturation phase value (saturated point) above and below (hatched portion) and the saturation phase value (saturated point) and below (shaded portion) in the direction in which the phase difference decreases (phase difference −) The characteristic of the vertical object around 90deg). This is due to the characteristics of the phase comparator 10 using the EXOR circuit. When random noise components are input to the phase comparator 10, the phase information approaches -90 deg.

  FIG. 4 is a diagram illustrating an example of input / output waveforms of the phase comparator 10 using the EXOR circuit. In the example shown in FIG. 4, A indicates a standard reference signal waveform, B indicates an error signal waveform that has passed through the bandpass filter 9, and C indicates an output signal waveform corresponding to the phase difference between A and B. In the phase comparator 10, the standard reference signal waveform and the error signal waveform are shaped into a square wave and then input to the EXOR circuit. In the example shown in FIG. 4, when the logics of A and B are different, the logic of C becomes high level. For example, when the phase difference between A and B is 0 deg, the duty of C is 0%, when C is −90 deg, the duty of C is 50%, and when C is −180 deg, the duty of C is 100%. However, when noise is superimposed on A, the duty of C is offset in a direction approaching 50%.

  FIG. 5 is a diagram illustrating an example of input / output phase characteristics of the phase comparator 10 using the EXOR circuit. In the example shown in FIG. 5, the input phase difference (true value) indicates the true (calculated) phase difference between A and B, and the output phase difference is obtained when A and B are input to the phase comparator 10. The detected phase difference (corresponding to C) is shown. As shown in FIG. 5, the output phase difference is offset in a direction approaching −90 deg with the duty approaching 50% from the input phase difference (true value) according to the amount of noise.

  As a result, as shown in FIG. 3, the saturation phase value of the phase difference detected by the phase comparator 10 approaches -90 deg as the amount of disturbance noise increases (in the direction of the arrow in the figure), and the phase characteristic becomes a linear characteristic. The range becomes narrower. Such characteristics can be detected by changing the gain, and it can be determined that there is disturbance noise. However, in this case, the servo characteristics are not optimal, and this affects the device operation (setup operation, reading operation). There is.

  Therefore, in this embodiment, in principle, the phase of the signal input to the phase comparator 10 is manipulated by changing the characteristics of the bandpass filter 9 (hereinafter referred to as “BPF characteristics”) with a certain fixed gain value. The phase difference detected by the phase comparator 10 is intentionally saturated to detect disturbance noise (that is, the disturbance noise is detected based on the linearity characteristic of the phase change). As a result, since the circuits and settings in the servo loop are not changed, disturbance noise can be detected without affecting the servo operation.

  FIG. 6 is a diagram showing an example of the relationship between the phase difference detected by the phase comparator 10 when the BPF characteristic is changed and the gain in the servo loop when there is disturbance noise, and FIG. It is a figure which shows the phase characteristic when a characteristic is changed. As shown in FIGS. 6 and 7, when the BPF characteristic, specifically, the set phase value (set center frequency) in the bandpass filter 9 is changed, the phase characteristic changes greatly with an arbitrary fixed gain value.

  Specifically, the microcomputer 16 changes the set phase value (set center frequency) to be set in the band-pass filter 9 stepwise (gradually), whereby the error signal passing through the band-pass filter 9 is changed. Control to change the phase step by step. Then, the microcomputer 16 takes in a value corresponding to the phase difference detected a plurality of times by the phase comparator 10 in the process in which the set phase value of the bandpass filter 9 is changed stepwise, and a value corresponding to the phase difference. When the amount of change becomes a predetermined amount (hereinafter referred to as “saturation detection threshold”) or less, it is determined that there is disturbance noise.

  FIG. 8 is a diagram illustrating an example of input / output waveforms of the phase comparator 10 in a process in which the phase of the error signal passing through the bandpass filter 9 is changed in stages (A, B, and C in FIG. Same as in FIG. As shown in FIG. 8A, when there is no disturbance noise, the duty of C is 50% in the initial state where the phase difference between A and B is −90 deg. When 45 deg is changed (shifted), the duty of C becomes 75% (phase difference = −90 deg−45 deg), and when the B phase is changed −90 deg (shifted), the duty of C becomes 100% (phase difference = −90 deg). Since the detected phase difference between A and B changes linearly to -180 deg., The microcomputer 16 does not determine that the amount of change in the value corresponding to the phase difference is less than or equal to the saturation detection threshold. On the other hand, as shown in FIG. 8B, when there is disturbance noise, the duty of C is 50% in the initial state where the phase difference between A and B is −90 deg. If the phase of C is changed by -90 deg (shifted), the duty of C becomes 100% + α (the detected phase difference between A and B is −180 deg + α) and is saturated, so the microcomputer 16 has a value corresponding to the phase difference. It is determined that the change amount is equal to or less than the saturation detection threshold.

  Next, a first embodiment of disturbance noise determination processing in the microcomputer 16 will be described with reference to FIGS.

  FIG. 9 is a flowchart illustrating an example of disturbance noise determination processing in the microcomputer 16 according to the first embodiment. FIG. 10 is a diagram illustrating an example of the relationship between the phase difference detected by the phase comparator 10 and the gain in the servo loop in the disturbance noise determination process according to the first embodiment. FIG. 11 is a diagram illustrating the relationship between the phase difference detected by the phase comparator 10 and the set phase value in the bandpass filter 9 in the first embodiment.

  As a premise of the disturbance noise determination process shown in FIG. 9, the microcomputer 16 sets two threshold values F1 and F2 that are boundaries for disturbance noise determination, and a saturation detection threshold value. As shown in FIG. 10, the threshold value F1 is set in a direction in which the phase difference decreases with respect to the gain, and the threshold value F2 is set in a direction in which the phase difference increases with respect to the gain. The threshold values F1 and F2 are determined in consideration of a saturation point when a disturbance noise of a level to be detected is applied, for example. As a result, disturbance noise that does not hinder the operation of the apparatus is not detected.

  When the processing shown in FIG. 9 is started, the microcomputer 16 first determines a set phase value (set center frequency) to be set in the bandpass filter 9, and holds the set phase value in the internal memory as a BPF initial reference value. (Store) and a setting command for setting the set phase value is given to the band pass filter 9 (step S1). Thereby, the band pass filter 9 sets the set phase value, and the phase comparator 10 detects the phase difference between the error signal passing through the band pass filter 9 set with the set phase value and the reference reference signal. become. The BPF initial reference value is an arbitrary fixed gain value, and is set so that the phase difference between the reference signal and the error signal that has passed through the bandpass filter 9 is −90 deg.

  Next, the microcomputer 16 takes in (measures) a value corresponding to the phase difference detected by the phase comparator 10 (step S2) and stores it in the internal memory as the phase value α.

  Next, as shown in FIG. 11, the microcomputer 16 lowers the set phase value by one step (step) (for example, lowers an arbitrary decrease width X) and holds the set phase value by one step in the internal memory. In addition, a change command for changing (shifting) the set phase value is given to the band-pass filter 9 (step S3). Thus, the band pass filter 9 changes the set phase value, and the phase comparator 10 detects the phase difference between the error signal that has passed through the band pass filter 9 with the set phase value changed and the reference reference signal. become.

  Next, the microcomputer 16 captures (measures) a value corresponding to the changed phase difference detected by the phase comparator 10 (step S4), and stores it in the internal memory as the phase value β.

  Next, the microcomputer 16 calculates the phase value variation γ (γ = | β−α |) using the phase value α and the phase value β fetched from the phase comparator 10 (step S5).

  Next, the microcomputer 16 determines whether or not the calculated change amount γ of the phase value is less than or equal to the saturation detection threshold (step S6), and when the change amount γ is less than or equal to the saturation detection threshold (that is, the level). If the phase difference is saturated (step S6: YES), the process proceeds to step S7. If the change amount γ is not equal to or less than the saturation detection threshold (step S6: NO), the process proceeds to step S8.

  In step S7, the microcomputer 16 determines that there is external noise, and ends the process. In this way, when the microcomputer 16 determines that there is disturbance noise (that is, detection of disturbance noise), the microcomputer 16 performs processing corresponding to the detection of disturbance noise (for example, processing such as stopping gain adjustment or stopping the reproduction operation). become.

  On the other hand, in step S8, the microcomputer 16 determines whether or not the set phase value δ (that is, the latest set phase value) when the change amount γ is not less than or equal to the saturation detection threshold is less than or equal to the threshold F1. If the set phase value δ is not equal to or less than the threshold value F1 (step S8: NO), the process returns to step S2, and the phase value change amount γ is equal to or less than the saturation detection threshold value, or the set phase value The above process is repeated until δ becomes equal to or less than the threshold value F1. In this process, when the set phase value of the bandpass filter 9 is changed stepwise, the phase of the error signal passing through the bandpass filter 9 is changed stepwise. On the other hand, when the set phase value δ is equal to or less than the threshold value F1 (step S8: YES), the microcomputer 16 determines that there is no external noise (step S9) and ends the process.

  Note that the disturbance noise determination process shown in FIG. 9 is a disturbance noise determination process in a direction in which the phase difference decreases with respect to the gain (in which the set phase value of the bandpass filter 9 is changed stepwise). The basic process flow is the same in the disturbance noise determination process in the direction in which the phase difference increases with respect to the gain (the set phase value of the bandpass filter 9 is changed stepwise in the increasing direction). In the case of disturbance noise determination processing in the direction in which the phase difference increases with respect to the gain, in step S3, the microcomputer 16 increases the set phase value by one step (step) as shown in FIG. The set phase value increased by one step is held in the internal memory, and a change command for changing (shifting) the set phase value is given to the band-pass filter 9. In this case, in step S8, the microcomputer 16 determines whether or not the set phase value ε when it is determined that the amount of change γ is not less than or equal to the saturation detection threshold is greater than or equal to the threshold F2. If the set phase value ε is not equal to or greater than the threshold value F2, the process returns to step S2. If the set phase value ε is equal to or greater than the threshold value F2, the process proceeds to step S9.

  As described above, according to the first embodiment, the microcomputer 16 changes the set phase value to be set in the bandpass filter 9 stepwise, and the set phase value of the bandpass filter 9 is changed stepwise. In this process, when the amount of change in the value corresponding to the phase difference detected multiple times by the phase comparator 10 becomes equal to or less than the saturation detection threshold, it is determined that there is disturbance noise. Without providing, disturbance noise can be detected with high accuracy. That is, according to the present embodiment, since the servo loop phase information is used, it is possible to detect disturbance noise without affecting the servo operation such as the operation range being narrowed.

  Further, since disturbance noise can be detected even when information is read from the optical disc D, the disturbance noise can be detected at an arbitrary position or all around the optical disc D.

  In addition, since the bandpass filter 9 and the phase difference detector 10 can both use the existing circuit configuration, they can be realized without adding a new configuration.

  Next, a second embodiment of disturbance noise determination processing in the microcomputer 16 will be described with reference to FIGS.

  In the second embodiment, the microcomputer 16 takes in a value corresponding to the phase difference detected a plurality of times by the phase comparator 10 in the process of stepwise changing in the direction in which the set phase value of the bandpass filter 9 decreases. A process of holding the set phase value of the bandpass filter 9 when the change amount of the phase difference is equal to or less than the saturation detection threshold and changing the set phase value of the bandpass filter 9 stepwise in an increasing direction. In the phase comparator 10, the set phase value of the band-pass filter 9 when the amount of change in the value corresponding to the phase difference is equal to or less than the saturation detection threshold is held, When the phase width with the two set phase values held above is a predetermined width (hereinafter referred to as “saturation phase width detection threshold”) or less, it is determined that there is disturbance noise. That. Thereby, the detection accuracy of disturbance noise can be improved.

  FIG. 12 is a flowchart illustrating an example of disturbance noise determination processing in the microcomputer 16 according to the second embodiment. FIG. 13 is a diagram illustrating the relationship between the phase difference detected by the phase comparator 10 and the set phase value in the bandpass filter 9 in the second embodiment.

  In the second embodiment, as a premise of the disturbance noise determination process shown in FIG. 12, the microcomputer 16 includes, as shown in FIG. 13, in addition to the two threshold values F1 and F2 that are the boundaries of the disturbance noise determination and the saturation detection threshold value. , Two thresholds F3 and F4 for defining the saturation phase width detection threshold are set.

  The processes in steps S11 to S16 shown in the disturbance noise determination process shown in FIG. 12 are the same as the processes in steps S1 to S6 shown in the disturbance noise determination process shown in FIG.

  Next, when the change amount γ of the phase value calculated in step S15 becomes less than or equal to the saturation detection threshold (step S16: YES), the microcomputer 16 proceeds to step S17, and the change γ is less than or equal to the saturation detection threshold. If not (step S16: NO), the process proceeds to step S18.

  In step S17, the microcomputer 16 holds the set phase value δ when it is determined that the change amount γ is equal to or less than the saturation detection threshold in the internal memory, and the process proceeds to step S20.

  On the other hand, in step S18, the microcomputer 16 determines whether or not the set phase value δ when it is determined that the change amount γ is not less than or equal to the saturation detection threshold value is less than or equal to the threshold value F1, and the set phase value δ is determined. Is not less than or equal to the threshold value F1 (step S18: NO), the process returns to step S12 and the above process is repeated. On the other hand, when the set phase value δ is equal to or smaller than the threshold value F1 (step S18: YES), the microcomputer 16 determines the set phase value δ when it is determined that the set phase value δ is equal to or smaller than the threshold value F1 as the threshold value. F1 is stored in the internal memory (step S19), and the process proceeds to step S20.

  In step S20, the set phase value to be set in the bandpass filter 9 is returned to the BPF initial reference value, and a setting command for setting the set phase value is given to the bandpass filter 9.

  Next, the microcomputer 16 takes in (measures) a value corresponding to the phase difference detected by the phase comparator 10 (step S21) and stores it in the internal memory as the phase value α.

  Next, the microcomputer 16 increases the set phase value by one step, holds the set phase value increased by one step in the internal memory, and issues a change command for changing (shifting) the set phase value. (Step S22).

  Next, the microcomputer 16 takes in a value corresponding to the changed phase difference detected by the phase comparator 10 (step S23) and holds it as a phase value β in the internal memory.

  Next, the microcomputer 16 uses the phase value α and the phase value β fetched from the phase comparator 10 to calculate the phase value change amount γ (γ = | β−α |) (step S24).

  Next, the microcomputer 16 determines whether or not the calculated phase value change amount γ is equal to or less than the saturation detection threshold value (step S25), and when the change amount γ is equal to or less than the saturation detection threshold value ( Step S25: YES), the process proceeds to step S26, and if the change amount γ is not less than or equal to the saturation detection threshold (step S25: NO), the process proceeds to step S27.

  In step S26, the microcomputer 16 holds the set phase value ε when it is determined that the change amount γ is equal to or less than the saturation detection threshold in the internal memory, and the process proceeds to step S29.

  On the other hand, in step S27, the microcomputer 16 determines whether or not the set phase value ε when it is determined that the change amount γ is not less than or equal to the saturation detection threshold is greater than or equal to the threshold F2, and the set phase value ε Is not greater than or equal to the threshold value F2 (step S27: NO), the process returns to step S21 and the above process is repeated. On the other hand, when the set phase value ε is greater than or equal to the threshold value F2 (step S27: YES), the microcomputer 16 determines the set phase value ε when the set phase value ε is greater than or equal to the threshold value F2 as the above threshold value. F2 is stored in the internal memory (step S28), and the process proceeds to step S29.

  In step S29, the microcomputer 16 calculates the phase width W (W = | ε−δ |) using the set phase value δ held in step S19 and the set phase value ε held in step S28. .

  Next, the microcomputer 16 determines whether or not the calculated phase width W is equal to or smaller than the saturation phase width detection threshold determined from the thresholds F3 and F4 (step S30), and the phase width W is detected as the saturation phase width. If it is below the threshold (step S30: YES), it is determined that there is external noise (step S31). If the phase width W is not below the saturation phase width detection threshold (step S30: NO), external noise is present. It determines with there being nothing (step S32), and the said process is complete | finished.

  As described above, according to the second embodiment, in addition to the effects of the first embodiment, even if the initial gain varies due to variations in load resistance, ACT sensitivity, etc., the linear range (width) of the phase has a gain variation. Therefore, the detection accuracy can be improved. That is, even if the initial gain changes, the initial gain variation can be offset by looking at the vertical width.

  In the above embodiment, the case where the disturbance noise determination device of the present application is applied to the optical disc recording / reproducing device has been described. However, the present invention can also be applied to other information recording / reproducing devices constituting a servo loop. . The present application is particularly effective as a means for suppressing current consumption and temperature rise in an apparatus that is expected to perform high-speed recording / reproduction.

DESCRIPTION OF SYMBOLS 1 Driver 2 Spindle motor 3 Optical pick-up 4 RF amplifier 5 Gain variable amplifier 6 Adder 7 Phase compensation equalizer 8 Oscillator 9 Band pass filter 10 Phase comparator 11 Gain judgment window 12 Audio / video signal processing memory control 13 Memory 14 DAC
15 Display Control Unit 16 Microcomputer S Optical Disk Recording / Reproducing Device

Claims (4)

A disturbance noise determination device for determining the presence or absence of disturbance noise in a servo loop of a device capable of reading information from an information recording medium,
A reference reference signal generating means for generating a reference reference signal of a predetermined frequency;
Adding means for adding the standard reference signal to an error signal in the servo loop;
Filter means for passing the predetermined frequency component of the error signal to which the standard reference signal has been added, and phase difference detection for detecting a phase difference between the phase of the standard reference signal and the phase of the error signal that has passed through the filter means Means,
A phase control means for changing the phase of the error signal passing through the filter means stepwise by changing the set phase value of the filter means stepwise;
When the amount of change in the value corresponding to the phase difference detected multiple times by the phase difference detection means in the process of changing the set phase value of the filter means in stages is less than or equal to a predetermined amount, the disturbance noise Disturbance noise judging means for judging that
Disturbance noise determination device comprising: In the disturbance noise determination apparatus according to claim 1,
The phase control means changes the setting phase value of the filter means stepwise in a decreasing direction and changes the setting phase value of the filter means stepwise.
The disturbance noise determining means is provided with a change amount of a value corresponding to the phase difference detected a plurality of times by the phase difference detecting means in the process of stepwise changing the set phase value of the filter means. The phase difference detecting means detects the set phase value of the filter means when it becomes less than the fixed amount and is detected by the phase difference detecting means a plurality of times in the process of changing stepwise in the direction in which the set phase value of the filter means increases. The set phase value of the filter means when the amount of change of the value corresponding to the phase difference becomes a predetermined amount or less is held, and the phase width between the two set phase values held is a predetermined width or less. In some cases, the disturbance noise determination apparatus determines that the disturbance noise is present. A disturbance noise determination method for determining the presence or absence of disturbance noise in a servo loop of an apparatus capable of reading information from an information recording medium,
Generating a reference signal of a predetermined frequency;
Adding the reference signal to an error signal in the servo loop;
Detecting a phase difference between the position of the error signal that has passed through the filter means that passes the predetermined frequency component of the error signal to which the standard reference signal has been added, and the phase of the standard reference signal;
Changing the phase of the error signal passing through the filter means stepwise by changing the set phase value of the filter means stepwise;
A step of determining that the disturbance noise is present when a change amount of a value corresponding to the phase difference detected a plurality of times in a process in which a set phase value of the filter unit is changed stepwise is equal to or less than a predetermined amount. When,
Disturbance noise determination method comprising: A computer for determining the presence or absence of disturbance noise in a servo loop of a device capable of reading information from an information recording medium,
A reference reference signal generating means for generating a reference reference signal of a predetermined frequency;
Adding means for adding the standard reference signal to an error signal in the servo loop;
Filter means for passing the predetermined frequency component of the error signal to which the standard reference signal is added;
A phase difference detection means for detecting a phase difference between the phase of the reference reference signal and the phase of the error signal that has passed through the filter means;
A phase control means for changing the phase of the error signal passing through the filter means stepwise by changing the set phase value of the filter means stepwise; and
When the amount of change in the value corresponding to the phase difference detected multiple times by the phase difference detection means in the process of changing the set phase value of the filter means in stages is less than or equal to a predetermined amount, the disturbance noise A disturbance noise determination program that functions as a disturbance noise determination means for determining whether or not there is a disturbance noise.

Images