JPH08255357A - Optical recording and reproducing device - Google Patents

Abstract

PURPOSE: To precisely perform the control of high speed seek operation with circuit constitution capable of correcting an offset occurring in a binarization processing circuit for controlling the seek operation. CONSTITUTION: A CPU 23 reads a generated tracking error signal by an A/D converter 16D, and measures a higher and lower end voltages, and calculates the intermediate voltage of the tracking error signal from the values. Then, a pulse edge detection circuit 17E detects edges of rise and fall of a pulse of a binarization pulse signal binarized through a binarization preprocessing circuit 17A and a comparator 17B. The calculated intermediate voltage is made a proper slice level, and the intermediate voltage of the tracking error signal continuously read by the A/D converter 16D is detected, and a D/A converter 22A is controlled so that the period when the intermediate voltage is detected becomes simultaneous with the period when the edge of the binarization pulse signal is detected and offset correction operation in an offset correction circuit 16A is performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / reproducing device such as an optical digital device, and more particularly to an optical recording / reproducing device for controlling the high-speed seek operation with high accuracy.

[0002]

2. Description of the Related Art Generally, in an optical recording / reproducing apparatus such as the one described above, seek operation is controlled by using a signal obtained by binarizing a tracking error signal by a binarizing circuit. In this case, the tracking error signal is for the purpose of performing tracking control, and an offset correction circuit for correcting the offset of the tracking error signal is inserted before and after in such a tracking control system.

That is, in this offset correction, the tracking error signal passed through the offset correction circuit is converted into an A / D signal.
After the data is read into the CPU (Central Processing Unit) via the (analog / digital) conversion circuit and subjected to predetermined processing, D /
By feeding back to the offset correction circuit via the A (digital / analog) conversion circuit, the offset in the tracking error signal is corrected.

The tracking error signal with the offset thus corrected is supplied to the linear motor for moving the optical head and the actuator for controlling the objective lens in the optical head via the tracking servo signal processing circuit. Thus, tracking control is performed.

By the way, the control of the above-mentioned seek operation is
The output of the offset correction circuit for the tracking error signal is performed by using the binarized pulse signal binarized by the binarization processing circuit.

Therefore, the offset correction circuit is substantially used also as a tracking servo signal processing circuit for performing tracking control and a binarization processing circuit for controlling seek operation.

However, in the binarization processing circuit for controlling the seek operation, since there is no correction circuit for the offset that occurs, a circuit element with low offset generation is used. When the speed of the binarization processing circuit is increased in order to perform the seek operation at high speed, for example, in a circuit using a high speed operational amplifier or the like, an offset is likely to occur and it is difficult to configure a circuit corresponding to the high speed seek operation.

[0008]

As described above, in the binarization processing circuit for controlling the seek operation, there is no correction circuit for the generated offset, so that a circuit element with low offset generation is used. When the speed of the binarization processing circuit is increased in order to perform the seek operation at high speed, for example, in a circuit using a high speed operational amplifier or the like, an offset is likely to occur and it is difficult to configure a circuit corresponding to the high speed seek operation. was there.

Therefore, the present invention has a circuit configuration capable of correcting the offset generated in the binarization processing circuit for controlling the seek operation, and can control the seek operation at high speed with high accuracy. It is an object to provide an optical recording / reproducing device.

[0010]

The optical recording / reproducing apparatus of the present invention is an optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto an optical recording medium. Tracking error signal detecting means for detecting a tracking error signal based on the reflected light of the light beam applied to the recording medium, and offset correcting means for correcting the offset of the tracking error signal detected by the tracking error signal detecting means, Binarizing means for binarizing the tracking error signal detected by the tracking error signal detecting means, and detecting the rising and falling edges of the pulse of the binarized pulse signal binarized by the binarizing means. Detected by the pulse edge detection means and the tracking error signal detection means The calculating means for calculating the intermediate voltage from the upper and lower voltage ends of the racking error signal, the intermediate voltage calculated by the calculating means in the tracking error signal detected by the tracking error signal detecting means and the pulse edge detecting means. It comprises a control means for controlling the offset correction means so that edge detection is performed simultaneously.

The optical recording / reproducing apparatus of the present invention is an optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto the optical recording medium, and irradiating the optical recording medium. Tracking error signal detecting means for detecting a tracking error signal based on the reflected light of the light beam, offset correcting means for correcting the offset of the tracking error signal detected by the tracking error signal detecting means, and the tracking error signal detecting means. Binarizing means for binarizing the tracking error signal detected by, and rising of the pulse of the binarized pulse signal binarized by the binarizing means,
Pulse edge detection means for detecting a falling edge, analog / digital conversion means for converting the tracking error signal detected by the tracking error signal detection means from analog to digital, and digital conversion by this analog / digital conversion means The calculating means for calculating the intermediate voltage between the upper voltage and the lower voltage of the code, the intermediate voltage calculated by the calculating means in the digital code converted by the analog / digital converting means and the edge detection of the pulse edge detecting means are simultaneously performed. And a control means for controlling the offset correction means.

The optical recording / reproducing apparatus of the present invention is an optical recording / reproducing apparatus for optically recording / reproducing information by irradiating an optical beam from an optical head onto the optical recording medium. A tracking error signal detecting means for detecting a tracking error signal based on the reflected light of the light beam, an offset correction circuit for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and the tracking error signal detecting means. A binarization processing circuit for binarizing a tracking error signal detected by a pulse, and a pulse for detecting a rising edge or a falling edge of a binarized pulse signal binarized by the binarization processing circuit. Detected by the edge detection circuit and the tracking error signal detection means An intermediate voltage is calculated from the upper end voltage and the lower end voltage of the racking error signal, and the intermediate voltage in the tracking error signal detected by the tracking error signal detecting means and the edge detection of the pulse edge detection circuit are simultaneously detected. It is composed of a CPU that controls the offset correction circuit.

The optical recording / reproducing apparatus of the present invention is an optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto the optical recording medium. A tracking error signal detecting means for detecting a tracking error signal based on the reflected light of the light beam, an offset correction circuit for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and the tracking error signal detecting means. A binarization processing circuit for binarizing a tracking error signal detected by a pulse, and a pulse for detecting a rising edge or a falling edge of a binarized pulse signal binarized by the binarization processing circuit. Detected by the edge detection circuit and the tracking error signal detection means An analog / digital converter that converts the racking error signal from analog to digital, and an intermediate voltage between the upper and lower end voltages of the digital code that is converted by this analog / digital converter is calculated, and converted by the above analog / digital converter. And a CPU that controls the offset correction circuit so that the intermediate voltage in the digital code and the edge detection of the pulse edge detection circuit are performed simultaneously.

[0014]

According to the present invention, in an optical recording / reproducing apparatus for irradiating a light beam from an optical head onto an optical recording medium to optically record and reproduce information, the reflected light of the light beam applied to the optical recording medium is changed. Based on this, the tracking error signal is detected by the tracking error signal detection means, the offset of the detected tracking error signal is corrected by the offset correction means, and the tracking error signal detected by the tracking error signal detection means is binarized. The pulse edge detection means detects the rising and falling edges of the pulse of the binarized pulse signal that has been binarized, and an intermediate voltage is obtained from the upper end voltage and the lower end voltage of the tracking error signal detected by the tracking error signal detection means. Calculated by the calculation means and detected by the tracking error signal detection means. That the edge detection of the intermediate voltage and the pulse edge detection means calculated by said calculation means in the tracking error signal is obtained so as to control the offset correction means so as to simultaneously.

The present invention is an optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto an optical recording medium, wherein the reflected light of the light beam irradiated on the optical recording medium is reflected. The tracking error signal is detected based on the tracking error signal detecting means, the offset of the detected tracking error signal is corrected by the offset correcting means, and the tracking error signal detected by the tracking error signal detecting means is binarized.
The pulse edge detection means detects the rising and falling edges of the pulse of the binarized binarized pulse signal, and the tracking error signal detected by the tracking error signal detection means is converted from analog to digital. And the intermediate voltage between the upper end voltage and the lower end voltage of the converted digital code is calculated by the calculating means,
The offset correction means is controlled so that the intermediate voltage calculated by the calculation means in the digital code converted by the analog / digital conversion means and the edge detection by the pulse edge detection means are performed simultaneously. .

The present invention is an optical recording / reproducing apparatus for irradiating a light beam from an optical head onto an optical recording medium to optically record / reproduce information. Based on this, the tracking error signal is detected by the tracking error signal detecting means, the offset of the detected tracking error signal is corrected by the offset correction circuit, and the tracking error signal detected by the tracking error signal detecting means is binarized. The rising edge and the falling edge of the pulse of the binarized binarized pulse signal are detected by the pulse edge detection circuit, and the upper end voltage and the lower end voltage of the tracking error signal detected by the tracking error signal detecting means are detected. Calculate the intermediate voltage and detect by the tracking error signal detection means In which the edge detection of the intermediate voltage and the pulse edge detection circuit is configured to control the offset correction circuit so that simultaneous in the tracking error signal.

The present invention relates to an optical recording / reproducing apparatus for irradiating a light beam from an optical head onto an optical recording medium to optically record / reproduce information, in which reflected light of the light beam emitted to the optical recording medium is reflected. Based on this, the tracking error signal is detected by the tracking error signal detecting means, the offset of the detected tracking error signal is corrected by the offset correction circuit, and the tracking error signal detected by the tracking error signal detecting means is binarized. The pulse edge detection circuit detects the rising and falling edges of the pulse of the binarized binarized pulse signal, and the tracking error signal detected by the tracking error signal detecting means is converted from analog to digital analog / digital. The upper limit voltage of the digital code converted by the converter The intermediate voltage of the lower end voltage is calculated, and the offset correction circuit is controlled so that the intermediate voltage in the digital code converted by the analog / digital converter and the edge detection of the pulse edge detection circuit are simultaneously performed. It is a thing.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows an optical disc device as an optical recording / reproducing device according to the present invention. That is, a groove (recording track) is spirally formed on the surface of an optical disc 1 as an optical recording medium including an optical disc, and the optical disc 1 is rotated by a spindle motor 2 at a constant speed, for example. It
The spindle motor 2 is controlled by a motor control circuit 18.

The optical disk 1 has a doughnut-shaped metal coating layer such as tellurium or bismuth, that is, a recording film, coated on the surface of a circular substrate made of glass or plastics, and the center of the metal coating layer. A notch, that is, a reference position mark is provided near the portion.

Recording / reproduction of information on / from the optical disc 1 is performed by an optical head 3 provided below the optical disc 1. The optical head 3 is fixed to a drive coil 13 that constitutes a drive unit of the linear motor 31, and the drive coil 13 is a linear motor control circuit 1.
Connected to 7.

A linear motor position detector 26 is connected to the linear motor control circuit 17, and the linear motor position detector 26 outputs a position signal by selecting the optical scale 25 provided on the optical head 3. To do.

Further, a permanent magnet (not shown) is provided on the fixed portion of the linear motor 31, and the drive coil 13 is excited by the linear motor control circuit 17 to cause the optical head 3 to move to the optical disk 1 of the optical disc 1. Moved radially.

An objective lens 6 is held on the optical head 3 by a wire or a leaf spring (not shown). The objective lens 6 is moved by a driving coil 5 in the focusing direction (optical axis direction of the lens) and driven. The coil 4 allows movement in the tracking direction (direction orthogonal to the optical axis of the lens).

The laser light generated by the laser diode 9 as a semiconductor laser oscillator driven by the laser control circuit 51 is irradiated onto the optical disk 1 through the collimator lens 11a, the half prism 11b and the objective lens 6, The reflected light from the optical disc 1 includes an objective lens 6, a half prism 11b, and a condenser lens 10.
The light is guided to the photodetector 8 via a and the cylindrical lens 10b.

In the vicinity of the laser diode 9, a monitor photodiode PD is provided as a light emission amount detecting device for detecting the light emission amount of the laser diode 9.
The monitor current as a detection signal from the photodiode PD is supplied to the laser control circuit 51.

The photodetector 8 is composed of four-divided photodiodes 8a to 8d. The cathodes of the photodiodes 8a to 8b of the optical head 3 are commonly connected to the preamplifier circuit 52 for video signals, and the anodes thereof are connected to the focus / tracking processing circuit 40, respectively.

As a result, a current flows from the cathode to the anode in the photodiodes 8a to 8d in response to the reflected light from the optical disk 1, and the video signal processing described later is performed by using the sum current extracted from the cathode side. The focus (optical disk 1 and objective lens 6), which will be described later, is performed using the respective currents extracted from the anode side.
Is kept constant) and tracking (according to the guide groove previously recorded on the optical disc 1) are performed.

Here, the focus / tracking processing circuit 40 includes a focusing control circuit 15, a tracking control circuit 16, a linear motor control circuit 17, and an adder 30.
a, differential amplifiers OP1 and OP2, and gain-switchable amplifiers 12a to 12d.

These amplifiers 12a to 12d are current-voltage converters for converting the current outputs of the photodiodes 8a to 8d into voltage signals, and are circuits having the same structure.

That is, the output signal of the photodiode 8a of the photodetector 8 is added to the adder 30 via the amplifier 12a.
a, 30c is supplied to one end. The output signal of the photodiode 8b is added to the adder 30 via the amplifier 12b.
It is supplied to one end of b and 30d.

The output signal of the photodiode 8c is supplied to the other ends of the adders 30b and 30c via the amplifier 12c. Further, the output signal of the photodiode 8d is supplied to the other ends of the adders 30a and 30d via the amplifier 12d.

The output signal of the adder 30a is supplied to the inverting input terminal of the differential amplifier OP1, and the output signal of the adder 30b is supplied to the non-inverting input terminal of the differential amplifier OP1.

As a result, the differential amplifier OP1 supplies the tracking control circuit 16 with a signal corresponding to the difference voltage between the adders 30a and 30b. This tracking control circuit 1
Reference numeral 6 has an offset correction circuit, which will be described later, and generates a track drive signal according to the track difference signal (tracking error signal) supplied from the differential amplifier OP1.

The track drive signal output from the tracking control circuit 16 is supplied to the drive coil 4 in the tracking direction in the optical head 3. Further, the track difference signal (tracking error signal) used in the tracking control circuit 16 is supplied to the linear motor control circuit 17.

The output signal of the adder 30c is supplied to the inverting input terminal of the differential amplifier OP2, and the differential amplifier OP2 is supplied.
The output signal of the adder 30d is supplied to the non-inverting input terminal of the. As a result, the differential amplifier OP2 includes the adder 30c,
A signal relating to the focus point is supplied to the focusing control circuit 15 according to the difference of 30d.

The output signal of the focusing control circuit 15 is supplied to the focusing drive coil 5 in the optical head 3 and is controlled so that the laser light is always in perfect focus on the optical disc 1.

The photodiode 8a of the photodetector 8 in the state where focusing and tracking are performed as described above.
The sum current of the outputs of 8d reflects the unevenness of the pits (recording information) formed on the track.

This sum current is converted into a voltage value by the preamplifier circuit 52 for the video signal, and the video signal processing circuit 19 is converted.
The video signal processing circuit 19 reproduces the synchronous clock, image data, and address data (track number, sector number, etc.).

A recording signal generation circuit 34 as a modulation circuit for modulating recording data supplied from an optical disk control device 33 as an external device through the interface circuit 32 into a recording pulse is provided in the preceding stage of the laser control circuit 51. Has been.

Further, the optical disk device has a focusing control circuit 15 and a tracking control circuit 1, respectively.
6. A D / A converter 22 used for exchanging information between the linear motor control circuit 17 and the CPU 23 is provided.

Further, the tracking control circuit 16 is
The objective lens 6 is moved according to the track jump signal supplied from the CPU 23 via the D / A converter 22,
The laser light is moved by one track.

The laser control circuit 51, the focusing control circuit 15, the tracking control circuit 16, the linear motor control circuit 17, the motor control circuit 18, the video signal processing circuit 19, the recording signal generating circuit 34, etc. are connected to the bus line 2.
It is controlled by the CPU 23 via 0, and the CPU 23 performs a predetermined operation by a program recorded in a ROM in a memory 24 having a RAM (random access memory) and a ROM (read only memory).

FIG. 1 shows the construction of the essential parts of the tracking control system and the seek control system omitted in FIG. 2 in the above-mentioned optical disk device according to the present invention. That is, in FIG. 1, at the time of tracking control, the tracking error signal from the differential amplifier OP1 shown in FIG. 2 has an offset correction circuit 16A as an offset correction means which constitutes the tracking control circuit 16 of FIG. 2, and a tracking servo signal processing circuit. The tracking control as described above is performed by being supplied to the drive coil (tracking actuator) 4 in the optical head 3 shown in FIG. 2 via 16B and the tracking driver 16c.

At this time, the seek control circuit 1 shown in FIG.
Switch SW controlled by 7C has contact a
The drive signal is supplied to the drive coil 13 of the linear motor 31 via the linear motor control circuit 17 shown in FIG. 2 according to the tracking error signal from the tracking servo signal processing circuit 16B.

FIG. 3A shows an example of the tracking error signal. The offset correction circuit 16A
Is an offset correction that outputs the tracking error signal via the D / A converter 22A after the tracking error signal is read into the CPU 23 via the A / D converter 16D as an analog / digital conversion means and subjected to predetermined arithmetic processing. Since the signal is supplied, it operates so as to cancel the offset generated in the tracking error signal.

On the other hand, when the seek operation is controlled, the switch SW controlled by the seek control circuit 17C.
Is located on the contact point b side, the tracking coil signal processing circuit 16B is provided in the drive coil 13 of the linear motor 31.
The tracking error signal from is cut, and instead the seek control circuit 17C is connected to the D / A converter 22B.
A drive signal is supplied to the linear motor 31 via the.

In this case, the seek control circuit 17C binarizes the tracking error signal via the binarization preprocessing circuit 17A and the comparator 17B which constitute the binarization processing circuit 17D as the binarization means. A binary pulse signal is supplied.

FIG. 3B shows the binarized pulse signal output from the comparator 17B. This 2
The digitized pulse signal is read by the CPU 23 by detecting the rising and falling timings of the pulse by the pulse edge detecting circuit 17E as the pulse edge detecting means.

Next, with reference to the flow chart of FIG. 4, the offset correction operation during the seek operation in the above-mentioned optical disk device having such a structure will be described. First, it is assumed that the optical disk device is in an operating state in which focusing is on and tracking is off. At this time, for example, a tracking error signal as shown in FIG. 3A is generated.

The CPU 23 reads the tracking error signal with the A / D converter 16D, measures the upper end voltage and the lower end voltage of the tracking error signal, calculates the intermediate voltage of the tracking error signal from the measured values, and calculates the intermediate voltage. The binarization slice level is appropriate.

Next, the CPU 23 continuously reads the tracking error signal by the A / D converter 16D, and at the same time, the pulse edge detection circuit 17E constitutes the binarization processing circuit 17D. The binarization preprocessing circuit 17A and the comparator 17B. The rising and falling edges of the pulse of the binarized pulse signal that is binarized via are detected.

The CPU 23 outputs the intermediate voltage of the tracking error signal continuously read by the A / D converter 16D and 2
The offset correction operation in the offset correction circuit 16A is performed by controlling the D / A converter 22A so that the edges of the binarized pulse signal are detected at the same time.

That is, D / is set so that the intermediate voltage in the tracking error signal as shown in FIG. 3A and the edge detection of the pulse of the binarized pulse signal as shown in FIG. By setting the output voltage of the A converter 22A, the offset generated in the binarization processing circuit 17D can be corrected.

As described above, according to the above embodiment,
By performing the offset correction operation such that the intermediate voltage of the tracking error signal and the edge detection of the binarized pulse signal are performed at the same time, the offset correction of the binarization processing circuit can be performed during the seek operation that requires high-speed processing. It is possible to perform highly accurate high-speed seek operation.

[0055]

As described above in detail, according to the present invention,
To provide an optical recording / reproducing apparatus capable of correcting a high-speed seek operation with high accuracy by a circuit configuration capable of correcting an offset generated in a binarization processing circuit for controlling a seek operation. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an offset correction system for tracking and seek operation control according to an embodiment of the present invention.

FIG. 2 is a diagram showing the overall configuration of an optical disk device as an embodiment of the present invention.

FIG. 3 is a diagram showing an example of a tracking error signal and a binarized pulse signal.

FIG. 4 is a flowchart for explaining an offset correction operation during a seek operation in the optical disk device.

[Explanation of symbols]

 1 ... Optical disc 16 ... Tracking control circuit 16A ... Offset correction circuit 16B ... Tracking servo signal processing circuit 16C ... Tracking driver 16D ... A / D converter 17 ... Linear motor control circuit 17A ... Binarization preprocessing circuit 17B ... Comparator 17C ... Seek control circuit 17D ... Binarization processing circuit 17E ... Pulse edge detection circuit 22A ... D / A converter 23 ... CPU

Claims (5)

[Claims] 1. An optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto an optical recording medium, wherein: A tracking error signal detecting means for detecting a tracking error signal, an offset correcting means for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and a tracking error signal detected by the tracking error signal detecting means. The binarizing means for binarizing, the pulse edge detecting means for detecting the rising and falling edges of the pulse of the binarizing pulse signal binarized by the binarizing means, and the tracking error signal detecting means. The upper and lower voltage of the detected tracking error signal Calculating means for calculating the intermediate voltage, and the offset so that the intermediate voltage calculated by the calculating means in the tracking error signal detected by the tracking error signal detecting means and the edge detection by the pulse edge detecting means are performed simultaneously. An optical recording / reproducing apparatus comprising: a control unit that controls a correction unit. 2. An optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto an optical recording medium, based on reflected light of the light beam irradiated onto the optical recording medium. A tracking error signal detecting means for detecting a tracking error signal, an offset correcting means for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and a tracking error signal detected by the tracking error signal detecting means. The binarizing means for binarizing, the pulse edge detecting means for detecting the rising and falling edges of the pulse of the binarizing pulse signal binarized by the binarizing means, and the tracking error signal detecting means. Analog to digital tracking error signal detected The analog / digital converting means for converting, the calculating means for calculating the intermediate voltage between the upper end voltage and the lower end voltage of the digital code converted by the analog / digital converting means, and the digital code converting by the analog / digital converting means An optical recording / reproducing apparatus comprising: a control unit that controls the offset correction unit so that the intermediate voltage calculated by the calculation unit and the edge detection of the pulse edge detection unit are performed simultaneously. 3. An optical recording / reproducing apparatus for optically recording / reproducing information by irradiating a light beam from an optical head onto an optical recording medium, based on reflected light of the light beam applied to the optical recording medium. A tracking error signal detecting means for detecting a tracking error signal, an offset correction circuit for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and a tracking error signal detected by the tracking error signal detecting means are provided. A binarization processing circuit that performs binarization processing, a pulse edge detection circuit that detects rising and falling edges of a pulse of the binarized pulse signal that has been binarized by the binarization processing circuit, and the tracking error. Upper end of tracking error signal detected by the signal detection means The intermediate voltage is calculated from the pressure and the lower end voltage, and the offset correction circuit is controlled so that the intermediate voltage in the tracking error signal detected by the tracking error signal detection means and the edge detection of the pulse edge detection circuit are performed simultaneously. An optical recording / reproducing apparatus comprising: 4. An optical recording / reproducing apparatus for optically recording and reproducing information by irradiating a light beam from an optical head onto an optical recording medium, based on reflected light of the light beam irradiated onto the optical recording medium. A tracking error signal detecting means for detecting a tracking error signal, an offset correction circuit for correcting an offset of the tracking error signal detected by the tracking error signal detecting means, and a tracking error signal detected by the tracking error signal detecting means are provided. A binarization processing circuit that performs binarization processing, a pulse edge detection circuit that detects rising and falling edges of a pulse of the binarized pulse signal that has been binarized by the binarization processing circuit, and the tracking error. The tracking error signal detected by the signal detection means is analyzed. Analog / digital converter for converting digital to digital and a digital code converted by the analog / digital converter by calculating an intermediate voltage between the upper voltage and the lower voltage of the digital code converted by this analog / digital converter 2. An optical recording / reproducing apparatus comprising: a CPU that controls the offset correction circuit so that the intermediate voltage and the edge detection of the pulse edge detection circuit are simultaneously performed. 5. An optical recording / reproducing apparatus for irradiating a light beam from an optical head onto an optical recording medium to optically record and reproduce information, wherein the optical recording medium is based on the reflected light of the light beam applied to the optical recording medium. The tracking error signal is detected, the detected tracking error signal is binarized, the rising and falling edges of the pulse of the binarized binarized pulse signal are detected, and the upper end voltage and the lower end of the tracking error signal are detected. Calculating a middle voltage from the voltage and controlling the offset correction of the detected tracking error signal so that the calculated middle voltage in the tracking error signal and the edge detection are simultaneous.