JP2003068035A - Information recording / reproducing device - Google Patents

Abstract

(57) [Problem] To provide an information recording / reproducing apparatus having good control performance with respect to both aperiodic disturbance and periodic disturbance. A low-pass filter and a delay means having a delay time smaller than the rotation period by a delay time of the filter form a repetitive control loop for a periodic rotation period component of a recording medium. Averaging in order to prevent the control gain from being reduced for non-periodic components other than the above is performed by forming a loop by means of coefficient multiplying means k and 1-k and delay means 5 and 7 having a total delay time equal to the rotation period. . Thereby, both the repetitive control and the averaging process can be performed accurately. Also, when there is no signal to be delayed or for a certain period thereafter, the averaging coefficient k is made larger than usual so that the effect of the repetitive control can be immediately exerted. When the characteristic is low, the averaging coefficient k is made smaller than usual so that the signal is not reflected in the subsequent control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device,
The present invention relates to an information recording / reproducing apparatus for recording / reproducing information on / from a recording medium by a head, such as a magneto-optical disk device or a magnetic disk device, and in particular, information recording / reproducing in which the relative position of the head to the recording medium is controlled with high accuracy. It relates to the device.

[0002]

2. Description of the Related Art One of the causes of the displacement of the relative position of a recording medium and a head in an information recording / reproducing apparatus is a periodic disturbance caused by the rotation of the recording medium.
Repetitive control is widely known as a method for improving control performance against this periodic disturbance. FIG. 13 shows this repetitive control circuit. The difference between the target value R (s) and the control amount (head position) Y (s) of the controlled object 3 is used as an error signal E (s) in the error detecting means 1. Obtained and input to the adder 9. The output of the adder 9 is added to the error signal E (s) via the low pass filter 4 and the delay means 6,
The output of the adder 9 passes through the stabilization compensator 2 and the drive signal D
(S) is added to the controlled object 3. Here, the delay time T−τ of the delay means 6 is the time obtained by subtracting the delay time τ of the low-pass filter 4 from the rotation period T of the recording medium.
In this way, by delaying the error signal by the rotation cycle of the recording medium, adding it to the original error signal that has not been delayed, and outputting the signal after addition to the stabilization compensator as a new error signal, The feedback control gain at the disturbance frequency can be made large. However, if repeated control is performed to delay the error signal itself, control stability is likely to be lost. Therefore, a low-pass filter 4 that removes high-frequency components of the error signal is provided, and the signal that has passed through this low-pass filter is delayed. , The stability is secured by adding to the error signal that has not passed through the low-pass filter (refer to Michio Nakano et al., December 1997), "Repetitive control" edited by the Society of Instrument and Control Engineers.

As described above, when the error signal is delayed by the rotation cycle of the recording medium and added to the original error signal which is not delayed, the control performance against the disturbance having the same cycle as the rotation cycle of the recording medium is greatly improved. However, for a disturbance having a period different from the rotation period of the recording medium, when added to the error signal after delaying the rotation period, this disturbance component is not necessarily added in phase with the same disturbance component in the error signal, The disturbance component may not be emphasized, but may be adversely affected. At this time, the control gain for the disturbance component is lowered, and the control performance is deteriorated. In order to solve this problem, JP-A-9-50
In Japanese Patent Laid-Open No. 303-303, in order to make the delayed and added signal only a signal having the same cycle as the rotation cycle of the recording medium, the delayed signal is averaged for each rotation cycle of the recording medium and repeatedly controlled. The technology is disclosed. This technique, as shown in FIG. 14, is a signal obtained by multiplying the output signal of the adder 9 by a gain k in order to improve control performance against unsteady disturbance such as scratches on the recording medium or vibration applied to the device. And a signal obtained by multiplying the signal delayed by the rotation period T of the recording medium by the gain (1-k) by the adder 8 and input to the delay means 6 to average the delayed signals. ing. The signal output from the delay unit 6 is passed through the low-pass filter 4 to remove high frequency components, and then added to the original error signal by the adder 9, and this output is used to drive the head drive unit of the optical disk device. Are in control.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the technique of Japanese Patent No. 0303, even if there is a disturbance of a frequency component different from the rotation period of the recording medium, this component is canceled by the averaging and is not added to the adder 9, so that the control stability is improved. . However, in order to average the delayed signals for each rotation cycle of the recording medium, the delay time of the delay means 6 in FIG. 14 must be the same as the rotation cycle of the recording medium. However, if the low-pass filter 4 is provided as described above, the control must be repeatedly performed with a delay time obtained by adding the delay time τ of the low-pass filter 4 to the delay time Τ of the delay unit 6, and the control performance is deteriorated. I can't avoid it.

An object of the present invention is to average delayed signals to prevent deterioration of control performance against disturbance having a period different from the rotation period of the recording medium, and to delay the delay time for repetitive control of the recording medium. An object of the present invention is to provide an information recording / reproducing apparatus including a control circuit configured to have the same rotation cycle.

[0006]

According to the present invention, there is provided an error signal detecting means for detecting a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing on the recording medium as an error signal, and this means. Second addition means for adding the error signal detected by the above as one input, a low pass filter for removing a high frequency component from the input signal using the output signal of the second addition means as an input, and an output of this low pass filter First signal with a value greater than or equal to 0 and less than or equal to 1
The first multiplication means for multiplying the coefficient, the first addition means for performing addition with the output signal of the first multiplication means as one input, and the output signal of the first addition means from the rotation cycle of the recording medium First delay means for applying a delay of a short time corresponding to the delay time of the low-pass filter and outputting the output signal as the other input to the second adding means;
Second delay means for delaying the output signal of the delay means by a time corresponding to the delay time of the low-pass filter;
Second multiplying means for multiplying the output signal of the second delay means by a second coefficient obtained by subtracting the first coefficient from 1 and outputting the output as the other input to the first adding means;
An information recording / reproducing apparatus is provided, which comprises: stabilization compensating means for performing compensation calculation on the output signal of the second adding means to generate a drive signal for the head.

Further, the present invention is an error signal detecting means for detecting, as an error signal, a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing on the recording medium.
A stabilizing compensating means for compensating the error signal detected by this means to output a stabilizing control signal, and a stabilizing control signal from this stabilizing compensating means are added as one input to the head for addition. A second adder that generates a drive signal, a low-pass filter that receives the output signal of the second adder and removes high-frequency components from the input signal, and a value of 0 or more and 1 or less for the output signal of the low-pass filter. First multiplying means for multiplying the first coefficient that it has,
An output signal of the first multiplying means and a first adding means for performing addition as one input, and a delay of an output signal of the first adding means, which is shorter than a rotation cycle of the recording medium by a delay time of the low-pass filter. Is provided to output the output signal as the other input to the second adding means, and a delay of a time corresponding to the delay time of the low-pass filter with respect to the output signal of the first delay means. A second delay means for giving the second output signal of the second delay means multiplied by a second coefficient obtained by subtracting the first coefficient from 1 and outputting the output as the other input to the first adding means; Disclosed is an information recording / reproducing apparatus, characterized in that it comprises: 2 multiplication means.

Further, the present invention further comprises an error signal detecting means for detecting, as an error signal, a relative positional deviation between a recording point on the recording medium and a head for recording / reproducing on the recording medium.
Second adding means for adding the error signal detected by this means as one input, and first multiplication for multiplying the output signal of the second adding means by a first coefficient having a value of 0 or more and 1 or less. Means, a first adding means for adding the output signal of the first multiplying means as one input, and a low-pass filter for removing the high frequency component from the input signal by using the output signal of the first adding means as an input; Delay means for delaying the output signal of the low-pass filter by a time shorter than the rotation cycle of the recording medium by the delay time of the low-pass filter and outputting the output signal as the other input to the second adding means; A high-pass filter having an output signal of the delay means as an input and having a gain characteristic that is the reciprocal of the gain characteristic of the low-pass filter, and 1 for the output signal of the high-pass filter. A second multiplication means for multiplying the second coefficient by subtracting the first coefficient and outputting the output as the other input to the first addition means, and a compensation operation for the output signal of the second addition means And a stabilization compensating means for generating a drive signal for the head.

Further, the present invention is an error signal detecting means for detecting, as an error signal, a relative positional deviation between a recording point on the recording medium and a head for recording / reproducing on the recording medium.
A stabilizing compensating means for compensating the error signal detected by this means to output a stabilizing control signal, and a stabilizing control signal from this stabilizing compensating means are added as one input to the head for addition. The second addition means for generating the drive signal, the first multiplication means for multiplying the output signal of the second addition means by the first coefficient having a value of 0 or more and 1 or less, and the output signal of the first multiplication means First adding means for performing addition as one input, a low-pass filter for removing a high frequency component from the input signal of the output signal of the first adding means, and a recording medium for the output signal of the low-pass filter. Delay means for delaying the rotation period by a delay time of the low-pass filter and outputting the output signal as the other input to the second adding means; Input signal, and a high-pass filter having a gain characteristic that is the reciprocal of the gain characteristic of the low-pass filter, and the output signal of this high-pass filter are multiplied by a second coefficient obtained by subtracting the first coefficient from 1 to obtain the output. An information recording / reproducing apparatus comprising: a second multiplying unit that outputs the other input to the first adding unit.

Further, according to the present invention, in the above-mentioned information recording / reproducing apparatus, when the level of the signal input to the first multiplying means is smaller than a predetermined value, the value of the first coefficient is set to a value larger than that in normal operation. In addition, when the frequency component corresponding to the rotation period of the recording medium included in the signal input to the first multiplication means is smaller than a predetermined value, the value of the first coefficient is set to a value smaller than that in normal operation. Disclosed is an information recording / reproducing apparatus, which is provided with variable coefficient control means for controlling so as to perform.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing a first embodiment of an information recording / reproducing apparatus of the present invention. A target value R (s) is a position of a track on which information is recorded or reproduced, a position where a laser is focused, or the like. This is the target value when the head follows. The error signal detecting means 1 detects the difference between the target value and the head position, and outputs an error signal E (s) representing the difference. The stabilization compensator 2 is based on the signal output from the adder 9
A drive signal D (s) for driving the head is output.
The stabilization compensator 2 is designed in consideration of control performance and stability, and is composed of, for example, a steady gain, a phase delay compensator, a phase lead compensator, and a notch filter. The controlled object 3 positions the head according to the drive signal D (s). This characteristic is the characteristic from the drive signal to the head position, and includes the characteristics of the driving means, the head, etc., which are not shown. The low-pass filter 4 removes a high frequency component of the signal output from the adder 9 to ensure stability of repetitive control. The low-pass filter 4 is preferably a filter (linear phase filter) that delays at the same time at all frequencies. However, if it is difficult to configure a linear phase filter, configure it with a filter close to its characteristic, such as a Butterworth filter, and its delay time is the same as the delay time of the linear phase filter closest to its phase characteristic. Interpret as there is.

The averaging gain k is obtained by multiplying the signal passed through the low pass filter 4 by the averaging coefficient k. Averaging coefficient k
Sets a value of 0 or more and 1 or less according to the state. Usually, it is set to a value larger than 0 and smaller than 1. The smaller this value is, the greater the effect of averaging becomes, and the control performance against the disturbance of a cycle different from the rotation cycle of the recording medium does not deteriorate, but when there is no delayed signal immediately after the start of repeated control. The effect of repetitive control, that is, the improvement of the control performance against the same disturbance as the rotation cycle of the recording medium,
It will not appear immediately. Therefore, when there is no signal to be delayed immediately after starting the repetitive control or for a certain period after that, the averaging coefficient k is made larger than the normal value, and then,
Switch to normal value. This switching can be easily realized by using a signal indicating the operating state from the control system of the device (not shown). Further, when the delay of the signal delayed due to scratches on the recording medium or shock to the device is low, the averaging coefficient k is set to a value larger than a normal value so as not to be reflected in the subsequent control. Make it smaller. This switching control has a periodicity if the level difference between the signal at the input point of the delay means 5 and the signal at the output point of the delay means 7, which will be described later, has a predetermined value, and if the level difference is greater than the predetermined value, there is a disturbance that disturbs the periodicity. It can be easily realized by a method of determining, a defect signal from a system indicating the presence of a scratch or a defect, and the like.

The delay means is divided into two parts, delay means 5 and 7, and the delay means 5 has a delay time T-τ with respect to the rotation period T of the recording medium and the delay time τ by the low-pass filter 4. The delay means 7 has a delay time τ. The averaging gain 1-k multiplies the signal output from the delay means 7 by (1-k). The adder 8 adds the signal multiplied by the averaging gain k and the signal multiplied by the averaging gain 1-k, and outputs it to the delay means 5. As a result, the delayed signals are averaged. The adder 9 outputs the output signal of the delay unit 5 delayed by a delay time τ of the low-pass filter 4 smaller than the rotation period T of the recording medium, and the error signal E (s) output from the error signal detection unit 1.
And are added, and the added signal is output as a new error signal to the low-pass filter 4 and the stabilization compensator 2.

The position of the low-pass filter 4 may be between the output of the averaging gain k and the input of the adder 8,
It may be between the output of the delay means 5 and the input of the adder 9. In any case, according to the configuration of FIG. 1, the delay signal to the adder 8 for averaging is delayed by the two delay means 5 and 7 for exactly the time T, and the adder for repetitive control is used. The delayed signal to 9 is also low-pass filter 4 and delay means 5.
The total delay time T is delayed.

The operation of the information recording / reproducing apparatus shown in FIG. 1 will be described below. 2 does not use repetitive control, FIG. 3 shows the case of FIG. 13, that is, it uses repetitive control, but does not average delayed signals, and FIG. 4 shows the case of FIG. 1, ie, the averaging coefficient k. Error signal E in the case of using repetitive control in which delayed signals are averaged by setting 0.25 to 0.25
It is a measurement example of the frequency response characteristic from (s) to the drive signal D (s). However, the cutoff frequency of the low-pass filter in the case of FIGS. 3 and 4 is 1 kHz.

The frequency response characteristics shown in FIGS. 3 and 4 when the repetitive control is used are the rotation frequency (153) of the recording medium.
The gain is large at a frequency that is an integral multiple of (Hz), which means that the control performance against periodic disturbance is high. However, in the case of using the repetitive control without averaging the delayed signals, in FIG. 3, the frequency is separated from the gain peak at the rotation frequency of the recording medium or the frequency that is an integral multiple thereof, particularly, adjacent peaks. Near the middle of the peak, the gain is smaller than the frequency response characteristic shown in FIG. 2 when the repetitive control is not used. At 1 kHz, for example, the gain is -20 dB or more in the case of FIG. 2, but the minimum value is -20 dB or less in the case of FIG. Therefore, it is shown that the control performance against aperiodic disturbance is lower when only the iterative control in FIG. 3 is used than when it is not used. However, in the case of the present invention of FIG. 4 in which the delayed signals are averaged and the repetitive control is used, a gain peak appears at the rotation frequency of the recording medium or a frequency that is an integral multiple thereof, and the adjacent peaks are Between frequencies, almost the same gain as the frequency response characteristic shown in FIG. 2 is shown, indicating that the control performance against aperiodic disturbance does not deteriorate.

FIGS. 5, 6, and 7 are examples of frequency spectrum measurement of an error signal in the information recording / reproducing apparatus corresponding to FIGS. 2, 3, and 4, respectively. Comparing FIG. 5 and FIG. 6, the error signal shown in FIG. 6 in the case of using the iterative control without averaging the delayed signals is compared to the error signal shown in FIG. 5 in the case of not using the iterative control. Thus, it can be seen that the periodic error signal (the portion of the line spectrum) becomes smaller, but the aperiodic error signal (the base portion other than the line spectrum) becomes larger. However,
The error signal shown in FIG. 7 when the delayed signals are averaged and the repetitive control is used is smaller in the periodic error signal and smaller in the aperiodic error signal than the error signal shown in FIG. The results are almost the same, and the results corresponding to the frequency characteristics of FIGS. 2 to 4 are obtained.

Next, in the information recording / reproducing apparatus of FIG.
Although it has been described that the averaging coefficient k is made larger than usual when there is no signal to be delayed immediately after the start of the repetitive control, or for a certain period after that, the effect will be described using an actual measurement example. FIG. 8 shows that when the averaging coefficient k is fixed at 0.25, FIG. 9 shows the first one cycle (about 0.00
(7 seconds) is the time response of the error signal when the averaging coefficient k is set to 1 and then the averaging coefficient k is set to 0.25, and the control is repeatedly started from the state where there is no signal to be delayed (repetition). Control starts at 0 seconds). Averaging coefficient k
In FIG. 8 in which is fixed at 0.25, the error signal converges about 0.04 seconds after starting the repetitive control. However, in FIG. 9 in which the averaging coefficient k is switched from 1 to 0.25, the error signal converges about 0.01 seconds after starting the repeated control. In this way, when there is no delayed signal immediately after starting repeated control, or for a certain period after that,
By making the averaging coefficient k larger than usual, the effect of repetitive control, that is, the improvement of the control performance against the same disturbance as the rotation cycle of the recording medium can be immediately exhibited.

Next, another configuration example of the present invention will be described. FIG. 10 is a modification of the information recording / reproducing apparatus of FIG. 1, and has the same configuration as that of FIG. 1 except that the stabilization compensator 2 is provided between the error signal detecting means 1 and the adder 9. With this structure, the same characteristics and effects as those of the first embodiment shown in FIG. 1 can be obtained.

FIG. 11 is a block diagram showing a second embodiment of the information recording / reproducing apparatus of the present invention. In the first embodiment shown in FIG. 1, the low-pass filter 4 is provided between the output of the adder 9 and the input of the averaging gain k, or between the output of the averaging gain k and the input of the adder 8, or It is provided between the output of the delay means 5 and the input of the adder 9, and both of them have the low-pass filter 4 outside the loop of the averaging process. On the other hand, in the second embodiment of FIG. 11, the position of the low-pass filter 4 is provided between the output of the adder 8 and the input of the delay means 5, and the delay means 5 is provided.
The delay time is T-τ obtained by subtracting the delay time τ of the low-pass filter 4 from the rotation period T of the recording medium. Also,
A high pass filter 10 is provided as shown instead of the delay means 7 of FIG. This high pass filter 10
Is provided to increase the high frequency component of the signal output from the delay means 5 and output it to the averaging gain 1-k. The gain characteristic of the transfer characteristic H (s) is the transfer characteristic of the low-pass filter 4. The gain characteristic is 1 / F (s) with respect to the characteristic F (s), or a characteristic close thereto. The phase characteristic of H (s) is 0 at all frequencies.
Alternatively, the characteristic is close to 0.

In FIG. 11, the low-pass filter 4
The position of may be immediately after the output of the delay unit 5. The position of the high pass filter 10 may be between the output of the averaging gain 1-k and the input of the adder 8. The characteristics and effects similar to those of the first embodiment can be obtained by FIG. 11 and the modified configurations thereof.

FIG. 12 shows a modification of the information recording / reproducing apparatus of FIG. 11, and is the same as FIG. 11 except that the stabilization compensator 2 is provided between the error signal detecting means 1 and the adder 9. It has the same configuration. Also with this configuration, the same characteristics and effects as those of the first embodiment can be obtained.

[0023]

According to the information recording / reproducing apparatus of the present invention, since the averaging process of delayed signals and the repeat control can be performed using accurate delay time, there is an effect that high control performance can be realized. In addition, when there is no delayed signal or during a certain period thereafter, the averaging coefficient is made larger than usual, so that the effect of repetitive control, that is, the improvement of the control performance against the same disturbance as the rotation cycle of the recording medium, can be immediately improved. Can be demonstrated. Further, when the periodicity of the delayed signal is low, the averaging coefficient can be made smaller than usual so that the signal is not reflected in the subsequent control.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an information recording / reproducing apparatus of the present invention.

FIG. 2 is an example of measurement of frequency response characteristics from an error signal to a drive signal when repetitive control is not used.

FIG. 3 is a measurement example of frequency response characteristics from an error signal to a drive signal when using repetitive control that does not average delayed signals.

FIG. 4 is a measurement example of frequency response characteristics from an error signal to a drive signal when the information recording / reproducing apparatus of the present invention is used.

FIG. 5 is an example of frequency spectrum measurement of an error signal when the repetitive control is not used.

FIG. 6 is an example of frequency spectrum measurement of an error signal in the case of using repetitive control without averaging delayed signals.

FIG. 7 is an example of frequency spectrum measurement of an error signal when the information recording / reproducing apparatus of the present invention is used.

FIG. 8 is a time response example of an error signal when the averaging coefficient is fixed to 0.25 in the information recording / reproducing apparatus of the present invention.

FIG. 9 is a time response example of an error signal when the averaging coefficient is variably controlled in the information recording / reproducing apparatus of the present invention.

10 is a block diagram showing a modified example of the information recording / reproducing apparatus of FIG.

FIG. 11 is a block diagram showing a second embodiment of the information recording / reproducing apparatus of the present invention.

12 is a block diagram showing a modified example of the information recording / reproducing apparatus of FIG.

FIG. 13 is a block diagram showing a configuration example of a conventional information recording / reproducing apparatus that does not use averaging processing.

FIG. 14 is a block diagram showing a configuration example of a conventional information recording / reproducing apparatus using an averaging process.

[Explanation of symbols]

1 Error signal detection means 2 Stabilization compensator 3 controlled objects 4 low pass filter 5, 6, 7 delay means 8 adder 9 adder 10 high pass filter k 1st averaging gain 1-k second averaging gain

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Man Satoshi             5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Stock             Ceremony Company within Hitachi Semiconductor Group F-term (reference) 5D096 RR02 RR06 RR15                 5D118 AA13 AA24 BA01 CA08 CA13                       CD03                 5H004 GA07 HA07 HB07 KA33 KB22                       KB38 LA03 LA13 MA12                 5H303 AA22 BB02 CC03 KK07 KK27

Claims (5)

[Claims] 1. An error signal detecting means for detecting a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing with respect to the recording medium as an error signal, and an error signal detected by this means. Second addition means for performing addition as one input, a low-pass filter for removing the high frequency component from the input signal of the output signal of the second addition means, and an output signal of the low-pass filter of 0 or more and 1 or less A first multiplication means for multiplying a first coefficient having a value; a first addition means for performing addition with the output signal of the first multiplication means as one input; and a recording medium for the output signal of the first addition means First delaying the output signal as the other input to the second adding means by giving a delay of a time shorter than the rotation cycle of the low pass filter by the delay time of the low pass filter.
Delay means; second delay means for delaying the output signal of the first delay means by a time corresponding to the delay time of the low-pass filter; and 1 to the first coefficient for the output signal of the second delay means. A second multiplication means for multiplying the second coefficient by subtracting and outputting the output as the other input to the first addition means; and a drive for the head by performing a compensation operation on the output signal of the second addition means. An information recording / reproducing apparatus comprising: a stabilizing compensating means for generating a signal. 2. An error signal detecting means for detecting a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing with respect to the recording medium, and an error signal detected by this means. Stabilizing compensating means for performing a calculation and outputting a stabilizing control signal; and second adding means for producing a drive signal for the head by adding the stabilizing control signal from the stabilizing compensating means as one input thereof. A low-pass filter that receives the output signal of the second adding means as input and removes high-frequency components from the input signal; and a first multiplication that multiplies the output signal of the low-pass filter by a first coefficient having a value of 0 or more and 1 or less. Means, first output means for performing addition as one input of the output signal of the first multiplication means, and a rotation cycle of the recording medium for the output signal of the first addition means. A first delay means for delaying the low-pass filter by a time shorter than that of the low-pass filter and outputting the output signal as the other input to the second adding means; Second delay means for giving a delay corresponding to the delay time of the low-pass filter, and the output signal of the second delay means are multiplied by a second coefficient obtained by subtracting the first coefficient from 1 and the output is multiplied by the first coefficient. An information recording / reproducing apparatus, comprising: a second multiplying unit that outputs the other input to the adding unit. 3. An error signal detecting means for detecting a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing on the recording medium as an error signal, and an error signal detected by the means. Second adding means for performing addition as one input, first multiplying means for multiplying an output signal of the second adding means by a first coefficient having a value of 0 or more and 1 or less, and an output of the first multiplying means A first addition means for performing addition with the signal as one input, a low-pass filter for removing a high frequency component from the output signal of the first addition means as an input, and recording for the output signal of the low-pass filter Delay means for delaying the rotation period of the medium by a delay time of the low-pass filter and outputting the output signal as the other input to the second adding means; A high-pass filter having an output signal of the delay means as an input and having a gain characteristic that is a reciprocal of the gain characteristic of the low-pass filter, and the output signal of the high-pass filter is multiplied by a second coefficient obtained by subtracting the first coefficient from 1 Second multiplying means for outputting the output as the other input to the first adding means, and stabilizing compensating means for performing a compensation operation on the output signal of the second adding means to generate a drive signal for the head, An information recording / reproducing apparatus comprising: 4. An error signal detecting means for detecting a relative positional deviation between a recording point of a recording medium and a head for recording / reproducing with respect to the recording medium, and an error signal detected by this means. Stabilizing compensating means for performing a calculation and outputting a stabilizing control signal; and second adding means for producing a drive signal for the head by adding the stabilizing control signal from the stabilizing compensating means as one input thereof. A first multiplication means for multiplying the output signal of the second addition means by a first coefficient having a value of 0 or more and 1 or less; and a first multiplication means for adding the output signal of the first multiplication means as one input thereof. Adder means, a low-pass filter that receives the output signal of the first adder means and removes high-frequency components from the input signal, and the rotation cycle of the recording medium with respect to the output signal of the low-pass filter. Further, a delay means for giving a delay time shorter by the delay time of the low-pass filter and outputting the output signal as the other input to the second adding means, and an output signal of the delay means as an input, A high-pass filter having a gain characteristic that is the reciprocal of the gain characteristic, and the output signal of this high-pass filter is multiplied by a second coefficient obtained by subtracting the first coefficient from 1 and the output is input to the other input to the first adding means. An information recording / reproducing apparatus comprising: a second multiplying unit for outputting as. 5. The information recording / reproducing apparatus according to claim 1, wherein the value of the first coefficient is changed when the level of the signal input to the first multiplying means is smaller than a predetermined value. When the frequency component corresponding to the rotation cycle of the recording medium included in the signal input to the first multiplication means is smaller than a predetermined value, the value of the first coefficient is set to a value larger than that in normal operation. An information recording / reproducing apparatus comprising a coefficient variable control means for controlling the value to be smaller than that during normal operation.