KR20040090108A - Apparatus and method for detecting wobble signal - Google Patents

Abstract

PURPOSE: A device for detecting a wobble signal and a method therefor are provided to sample and hold an erase power section to detect the first push-pull signal, and to sample and hold a recording power section to detect the second push-pull signal, then to synthesize the two signals to detect a wobble signal from the synthesized signals. CONSTITUTION: The first push-pull signal detector(100) samples electrical signals in an erase power section, and holds the signals in a recording power section to detect the first push-pull signal. The second push-pull signal detector(200) samples electrical signals in a recording power section, and to holds the signals in other section to detect the second push-pull signal. A synthesized signal generator(300) synthesizes the first and second push-pull signals. A wobble generator(400) detects a wobble signal from the synthesized signals. An A/D converter(500) converts the wobble signal into a digital signal.

Description

Apparatus and method for detecting wobble signal

The present invention relates to an apparatus and method for detecting a wobble (WBL) signal during recording in a system for recording or reproducing information by driving an optical disk.

Generally, compact discs and rewritable digital versatile discs (DVDs) are single spiral recording tracks that start at the center of the disc and end at the end of the disc. Has

At this time, CD-R, CD-RW, and the like are rewritable CDs, and DVD-RW, DVD-RAM, DVD-R, and the like are rewritable DVDs.

Among them, the CD-R / RW and DVD-RW / R record data only in the groove. At this time, the recording film is formed so that the recording of CD-R / DVD-R that can be recorded only once is possible only once. The recording film is an organic pigment, which is a recording for forming a hole by a high power laser.

The recording method in the CD-RW / DVD-RW in which the recording film is formed so as to be capable of repeatable recording is phase change recording, and data recording is performed as a difference between the reflectance between the crystalline state and the amorphous state.

Such CD-R / RW and DVD-R / RW pre-pit the land track to record position information on the groove track, and do not record data on the land track. In this case, the location information in the land is called land-pre-pit (hereinafter referred to as LPP) information. That is, information on the physical address of the groove track is recorded in the pits in advance in the land.

In addition, the position information may be recorded in a wobbling shape along the track boundary. Here, the wobbling is a modulated clock that modulates a constant clock to supply information to the disk, for example, information on the corresponding position, information about the rotation speed of the disk, and the like to the power of the laser diode, thereby controlling the information by changing the light beam of the laser. Is recorded at the boundary of the track.

At this time, the tracking error signal of the LPP region is generated large up and down with an arbitrary rule in the wobble signal. Therefore, in the case of the above-described CD-RW / R, DVD-RW / R, if the LPP signal or wobble signal previously recorded in the land is detected, address information indicating the track position can be detected.

Conventionally, when writing data to a rewritable optical disc, the erase power is controlled by using a sample & hold (S / H) method of holding an input signal in a recording power section and sampling in an erase power section. The wobble signal was detected only in the section. Here, the input signal is reflected light information A, B, C, D of the light spot emitted from the optical detector of the optical pickup to the disk. If the optical disc is a recordable optical disc only once, the wobble signal is detected by sampling the electrical signals A, B, C, and D in the read power section instead of the erase power section. The embodiment will now be described with respect to a rewritable disc.

Fig. 1 is a block diagram showing an example of such a conventional wobble signal detecting apparatus, wherein the optical pickup 10 allows light beams focused on an objective lens to be placed on a signal track of an optical disc, and also reflects and enters the signal recording surface. Is focused on the objective lens and then incident on the photodetector to detect the RF signal, the focus error signal and the tracking error signal. For example, if the optical detector is composed of four optical detection elements divided into four in the signal track direction and the radial direction of the optical disk, the respective optical detection elements of the optical detector detect the reflected light information from the recording track. . The reflected light information detected by each photodetecting element is converted into electrical signals A, B, C, and D in proportion to the detected light amount by a photoelectric conversion circuit (not shown), and the electrical signals A, B, C, and D are RF The signal is output to detect the focus error signal and the tracking error signal, which are the servo error signal, and is output to the sample & hold unit 11 for wobble detection.

The sample & hold section 11 samples the electrical signals A, B, C, and D output from the photo detector in the optical pickup 10 in accordance with a sample pulse input at the time of data recording. Holds the sampled electrical signals A, B, C, and D. Here, the sample signal is generated only in the erase power period.

That is, the sample & hold unit 11 samples the electrical signals A, B, C, and D in the erasure power section in which sample pulses are input during data recording, and in the recording power section in which sample pulses are not input. Holds the sampled electrical signals A, B, C, and D. The A and D signals sampled and held by the sample & hold unit 11 are output to the first gain control unit 12, and the B and C signals sampled and held are output to the second gain control unit 13. .

The first gain control unit 12 adjusts the gain so that the amplitude levels are the same for the sampled and held A and D signals, and adds them (A + D) to output them to the differential signal generator 14. The second gain control unit 13 performs gain adjustment so that the amplitude levels are the same for the sampled and held B and C signals, and then adds them (B + C) to output them to the differential signal generator 14.

The differential signal generator 14 is a difference A + D between the signal A + D output from the first gain controller 12 and the signal B + C output from the second gain controller 13. Obtain-(B + C) and output it to the wobble generator 15. That is, the differential signal generator 14 outputs a push-pull signal whose gain is adjusted by the first and second gain controllers 12 and 13.

The wobble generator 15 includes a band pass filter that passes only a frequency component corresponding to a wobble signal and removes other frequency components, and is included in the push-pull signal output from the differential signal generator 14. Detect the wobble signal.

As described above, the conventional wobble signal detection circuit detects the wobble signal only in the erasure power section by the sample & hold method.

In the conventional case described above, there is no problem in detection because the wobble frequency is very low compared to the pit frequency or the wobble frequency is low in the low speed recording.

However, when the wobble frequency becomes high frequency close to the pit frequency and goes to the high recording speed, the wobble frequency also increases accordingly, and according to the conventional method of detecting the wobble signal only in the erasure power section by the sample & hold method, Difficult to detect

That is, the conventional wobble detection apparatus detects the wobble signal using only a section other than the recording power section (i.e., the read power section for the disc which can be recorded once, and the erase power section for the disc which can be repeatedly recorded) during data recording. The faster the recording speed of the optical disc is, the less stable the sampled & held signal is, and especially a disc having a high frequency wobble has a lot of difficulty in detecting a wobble signal.

In addition, when the wobble signal is not detected, a problem occurs in the generation of the recording signal or the rotation control of the disc, which causes a problem in recording quality deterioration and recording servo.

To solve this problem, if the wobble signal is detected by sampling the entire section instead of the sample & hold method, in this case, the wobble signal is greatly distorted due to a large difference in signal size between recording and reproduction.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to accurately detect a wobble signal by a sample & hold method in a recording power section and an erase power section except for a recording transition section when data is written to a disc. An apparatus and method for detecting a wobble signal are provided.

1 is a block diagram of a conventional wobble signal detection device

2 is a block diagram of a wobble signal detection apparatus according to the present invention;

FIG. 3A is a waveform diagram showing an example of a push-pull signal detected in a rewritable disc of the present invention; FIG.

FIG. 3B is a waveform diagram showing an example of a first sample signal to be sampled in an erase power section of (a).

3C is a waveform diagram showing an example of a second sample signal to be sampled in the recording power section of (a).

3D is a waveform diagram showing an example in which the push-pull signal of (a) is sampled and held by the first and second sample signals of (b) and (c).

FIG. 4A is a waveform diagram showing an example of a push-pull signal detected on a write once disc of the present invention

4B is a waveform diagram showing an example of a first sample signal to be sampled in the read power section of (a).

4C is a waveform diagram showing an example of a second sample signal to be sampled in the recording power section of (a).

4D is a waveform diagram showing an example in which the push-pull signal of (a) is sampled and held by the first and second sample signals of (b) and (c).

Explanation of symbols for main parts of the drawings

10: optical pickup 100: first push-pull signal detector

101: first sample & hold unit 102: first gain control unit

103: second gain control unit 104: first differential signal generation unit

200: second push-pull signal detector 201: second sample & hold unit

202: third gain control unit 203: fourth gain control unit

204: second differential signal generator 300: synthesized signal generator

400: wobble generation unit 500: A / D conversion unit

600: LPP signal generator

The wobble signal detection apparatus according to the present invention for achieving the above object is divided into a land and a groove track, and detects the amount of reflected light from a recordable optical recording medium having a wobble signal recorded on any one of the tracks An optical pickup that outputs a proportional electrical signal and an electrical signal output from the optical pickup during data recording are sampled in an erasure power section, held in a recording power section, and then gain adjusted to the sampled & held signal. A first push-pull signal detector for detecting one push-pull signal and an electrical signal output from the optical pickup during data recording in a recording power section and holding in an erase power section and then adjusting the gain for the sampled & held signal A second push-pull signal detection unit configured to detect a second push-pull signal, and the first and second push-pull signals; A synthesized signal generator for synthesizing the first and second push-pull signals output from the call detector and a wobble generator for detecting a wobble signal by passing only a frequency component of a specific band from the push-pull signal synthesized by the synthesized signal generator Characterized in that it comprises a.

The first push-pull signal detector may be configured to sample an input signal in a read power section instead of the erase power section when the optical recording medium is an optical recording medium capable of recording once.

The second push-pull signal detector may hold an input signal in a read power section instead of the erase power section when the optical recording medium is a write once optical record medium.

The first push-pull signal detector samples the electrical signals A, B, C, and D output from the optical pickup in the erase power section according to the first sample signal to sample in the erase section when data is recorded. The first sample & hold unit for holding the sampled electrical signals A, B, C, D and the gain of the A, D signal sampled and held in the first sample & hold unit are respectively adjusted. A first gain control unit for adding and outputting signals, a second gain control unit for adjusting the gains of B and C signals sampled and held at the first sample & hold unit and outputting two signals after adding the two signals; And a first differential signal generator for outputting a difference between the A + D signal gained and adjusted by the first gain controller and the B + C signal gained and adjusted by the second gain controller.

The second push-pull signal detector samples the electrical signals A, B, C, and D output from the optical pickup in the recording power section according to the second sample signal to sample in the recording power section when data is recorded, and the erase power section. The second sample & hold unit holding the sampled electrical signals A, B, C, and D and the gains of the A and D signals that are sampled and held at the second sample & hold unit are respectively adjusted. A third gain control unit for adding and outputting signals, a fourth gain control unit for adjusting the gains of B and C signals sampled and held at the second sample & hold unit and outputting two signals after adding the two signals; And a second differential signal generator for outputting a difference between the A + D signal gained and adjusted by the third gain controller and the B + C signal gained and adjusted by the fourth gain controller.

When the synthesized signal generator combines the first push-pull signal and the second push-pull signal, a hold section of a predetermined section is generated between the sample of the recording power section and the sample signal of the erase power section in the synthesized sample & hold signal. The wobble generator may not detect the wobble signal in the hold period.

The wobble signal detection method according to the present invention is divided into a land and a groove track, and detects an amount of reflected light from a recordable optical recording medium having a wobble signal recorded on any one of the tracks, and outputs an electrical signal proportional thereto. And sampling the electrical signal output in the step at the time of data recording in the erasure power section, holding in the recording power section, and then adjusting the gain of the sampled & held signal to detect the first push-pull signal. And sampling the electrical signal output in the step at the time of data recording in the recording power section, holding in the erase power section, and then adjusting the gain of the sampled & held signal to detect the second push-pull signal. Synthesizing a first and a second push-pull signal, and frequency components of a specific band from the synthesized push-pull signal By passing the detecting a wobble signal, characterized in that formed.

The step is characterized by adjusting the level of the two sampled & held signals by increasing the gain of the first sampled & held signal and lowering the gain of the second sampled & held signal.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

Hereinafter, with reference to the accompanying drawings illustrating the configuration and operation of the embodiment of the present invention, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, By the technical spirit of the present invention described above and its core configuration and operation is not limited.

2 is a block diagram of a wobble signal detection apparatus according to the present invention, in which the electrical signals A, B, C, and D output from the optical pickup 10 during data recording are sampled in an erase power period, and in the recording power period. The first push-pull signal detector 100 which detects the first push-pull signal after holding and adjusting the gain, and records the electrical signals A, B, C, and D output from the optical pickup 10 during data recording. The second push-pull signal detector 200, the first and second push-pull signal detectors 100 and 200, which detect the second push-pull signal after sampling and holding gain in other sections, adjusts gain. A synthesized signal generator 300 for synthesizing the first and second push-pull signals, a wobble generator 400 for detecting a wobble signal from the push-pull signal synthesized by the synthesized signal generator 300, and the wobble generator Digital wobble signal detected at 400 Which consists of the A / D converter 500. The

A signal called WLDON is input to the synthesized signal generator 300. The synthesized signal generator 300 outputs the second push and the output of the first push-pull signal detector 100 when the WLDON is activated, that is, during recording. The output of the pull signal detection unit 200 is synthesized and output to the wobble generation unit 400, and when the WLDON signal is inactive, that is, during playback, only the push pull signal detected by the first push pull signal detection unit 100 is generated. Output to unit 400.

In addition, the first push-pull signal detector 100 samples the electrical signals A, B, C, and D output from the optical pickup 10 in the erase power section according to the first sample signal during data recording, and records the recording power section. The gain of the first sample & hold unit 101 for holding the sampled electrical signals A, B, C, and D, and the A and D signals output from the sample & hold in the first sample & hold unit 101 are output. The first gain control unit 102 to adjust the gain of the B and C signals that are sampled and held by the first sample & hold unit 101 and then output the adjusted gains. ), Generating a first differential signal outputting a difference between the A + D signal gained and adjusted by the first gain controller 102 and the B + C signal gained and adjusted by the second gain controller 103. It is composed of a section 104.

The second push-pull signal detector 200 samples and erases (or reads) electrical signals A, B, C, and D output from the optical pickup 10 in the recording power section according to the second sample signal during data recording. In the power section, the second sample & hold part 201 holding the sampled electrical signals A, B, C, and D, and the A & D signal outputted after being sampled & held by the second sample & hold part 201 are output. A third gain controller 202 for adjusting and adding the gain and a fourth gain controller for adjusting the gain of the B and C signals that are sampled and held by the second sample & hold unit 201 and outputting the adjusted gain. 203, a second differential outputting a difference between the A + D signal that is gain-adjusted and output from the third gain control unit 202 and the B + C signal that is gain-adjusted and output from the fourth gain control unit 203. The signal generator 204 is configured.

In FIG. 2, the LPP signal generator 600 may be connected to the synthesized signal generator 300 to detect LPP information from the synthesized push-pull signal.

The first sample signal is a signal for sampling in an erase period when data is recorded, for example, a high signal is an active signal as shown in FIG. 3, and the second sample signal is a signal for sampling in a recording power period when data is recorded. For example, as shown in FIG. 4, the high signal is an active signal.

FIG. 3 is a waveform diagram illustrating a sample & hold process when a disc is a repeatable recording medium, (a) is a push-pull signal detected in a repeatable recordable disc, and (b) is a first sample to be sampled in an erase power period. The sample signal, (c) is a second sample signal to be sampled in the recording power interval, (d) is a waveform diagram showing an example of the sample and hold the push-pull signal of (a) by the first and second sample signals. .

4 is a waveform diagram illustrating a sample & hold process when a disc is a write-once medium, (a) a push-pull signal detected on a write-once disc, and (b) a sample to read in a read power section. One sample signal, (c) is a second sample signal to be sampled in the recording power interval, (d) is a waveform diagram showing an example of the sample and hold the push-pull signal of (a) by the first and second sample signals to be.

In the present invention configured as described above, the optical pickup 10 causes the light beam focused on the objective lens to be placed on the signal track of the optical disk, and further condenses the light reflected from the signal recording surface into the objective lens and then RF signal and servo error signal. The detector is incident on the photo detector to detect an in-focus error signal and a tracking error signal. For example, if the photodetector is composed of four photodetectors divided into four in the signal track direction and the radial direction of the optical disk, the photodetector provides electrical signals A, B, C, and D proportional to the amount of reflected light. Outputs to the first and second push-pull signal detectors 100 and 200.

The first sample & hold unit 101 of the first push-pull signal detector 100 refers to a waveform of a first sample pulse (ie, FIG. 3 or FIG. 4B) to sample at an erase power interval when data is recorded. In the erase power section, the electrical signals A, B, C, and D output from the photo detector in the optical pickup 10 are sampled, and the sampled electrical signals A, B, C, and D are recorded in the recording power section. After the hold, the sampled and held A and D signals are output to the first gain controller 102, and the sampled and held B and C signals are output to the second gain controller 103.

The first gain control unit 102 increases the gain so that the amplitude level is the same with respect to the sampled and held A and D signals, and then adds two gain-adjusted signals (A + D) to form the first differential signal generator 104. Will output The second gain control unit 103 increases the gain so that the amplitude level is the same with respect to the sampled and held B and C signals, and then adds two gain-adjusted signals (B + C) to form the first differential signal generator 104. Will output

The first differential signal generator 104 may have a difference A + between the signal A + D output from the first gain controller 102 and the signal B + C output from the second gain controller 103. D)-(B + C) is obtained and output to the synthesized signal generator 300. That is, the differential signal generator 104 outputs a first push-pull signal whose gain is adjusted by the first and second gain controllers 102 and 103.

On the other hand, the second sample & hold unit 201 of the second push-pull signal detector 200 is a second sample pulse (that is, the waveform of FIG. In the recording power section, the electrical signals A, B, C, and D output from the photo detector in the optical pickup 10 are sampled. In the erasure power section, the sampled electrical signals A, B, C, and D are sampled. After holding, the sampled and held A and D signals are output to the third gain controller 202, and the sampled and held B and C signals are output to the fourth gain controller 203.

The third gain control unit 202 lowers the gain so that the amplitude level is the same with respect to the sampled and held A and D signals, and then adds two gain-adjusted signals (A + D) to generate the second differential signal generator 204. Will output The fourth gain control unit 203 lowers the gain so that the amplitude level is the same with respect to the sampled and held B and C signals, and then adds two gain-adjusted signals (B + C) to generate the second differential signal generator 204. Will output

In this case, the first and second gain control units 102 and 103 increase the gain with respect to the input signal, and the third and fourth gain control units 202 and 203 lower the gain with respect to the input signal. This is because is much larger than the signal of the erase (or read) power section, and the first and second push-pull signals, which are sampled and held at the rear end, are synthesized.

That is, the first and second gain control units 102 and 103 and the third and fourth gain control units 202 and 203 calculate respective gains from erasure and recording power, so that the signals obtained by the multi-pulse string during the recording are calculated. Adjust the size appropriately.

By doing so, it is possible to stably and accurately detect high-speed, high-frequency wobble signals during data recording.

On the other hand, the differential signal generator 204 is a difference (A +) between the signal A + D output from the third gain control unit 202 and the signal B + C output from the fourth gain control unit 203. D)-(B + C) is obtained and output to the synthesized signal generator 300. That is, the differential signal generator 204 outputs a second push-pull signal whose gain is adjusted by the third and fourth gain controllers 202 and 203.

The synthesized signal generator 300 detects the first push-pull signal and the second push-pull signal generator 200 detected by the first push-pull signal generator 100 according to the WLDON signal during recording. The 2 push-pull signals are synthesized as shown in FIG. 3 or 4 (d) and output to the wobble generator 400.

Meanwhile, the synthesized signal generator 300 outputs only the first push-pull signal detected by the first push-pull signal generator 100 to the wobble generator 400 according to a WLDON signal during reproduction.

The wobble generator 400 includes a band pass filter for passing only a frequency component corresponding to a wobble signal and removing other frequency components, and included in the synthesized push pull signal output from the synthesized signal generator 300. Detected wobble signal. In this case, since the wobble signal is an analog type, the wobble signal is output as it is and simultaneously output to the A / D converter 500 for digitization, and the A / D converter 500 digitizes and outputs the detected wobble signal.

In addition, the output of the composite signal generator 300 is also input to the LPP signal generator 600, the LPP signal generator 600 detects the LPP information from the synthesized push-pull signal.

At this time, when the synthesized sample & hold waveform of FIG. 3 or FIG. 4 is described, a hold section of a predetermined section is generated between the sample of the recording power section and the sample signal of the erase power section. At this time, the detection of the wobble signal is excluded in the hold period. That is, the unstable signal of the transition section in which the signal between the recording power section and the erase power section changes rapidly is excluded from the wobble detection.

As described above, the present invention can detect the wobble signal in most sections except the transition section in which the signal between the recording power section and the erase power section changes rapidly, so that the accurate wobble signal can be detected even on a disc having a high speed and high frequency wobble frequency. It becomes possible.

As described above, according to the wobble signal detecting apparatus and method according to the present invention, the first push-pull signal is detected by sampling and holding the erase (or read) power section when data is written to the optical disk, and the recording power section is sampled. By detecting & holding the second push-pull signal, combining the two signals and detecting the wobble signal from the synthesized push-pull signal, it is possible to stably and accurately detect the wobble signal and the LPP information even in a disk having a high speed and high frequency wobble frequency. have. That is, since the wobble signal is detected not only in the erasure (or read) power section but also in the recording power section at the time of data recording, the wobble detection capability can be improved when recording data at a high speed on an optical disk having a high frequency wobble frequency. Can improve the recording characteristics. In particular, since the detection of the wobble signal is excluded in the transition section in which the signal between the recording power section and the erase power section changes rapidly, the wobble signal can be detected more stably.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (13)

Wobble signal detection apparatus of an optical recording and reproducing system, which is divided into a land and a groove track, and performs recording and reproducing of data using power of a multi-pulse type on a recordable optical recording medium having a wobble signal recorded on any one of the tracks. To An optical pickup for detecting an amount of reflected light from the optical recording medium and outputting an electrical signal proportional thereto; The first push for sampling the electrical signal output from the optical pickup during data recording in the erase power section, holding in the recording power section, and then adjusting the gain of the sampled & held signal to detect the first push-pull signal. A full signal detector; A second push-pull signal that samples the electrical signal output from the optical pickup during recording, holds in the write power section, holds in the erase power section, and adjusts the gain of the sampled & held signal to detect the second push-pull signal. Detection unit; A synthesized signal generator for synthesizing the first and second push-pull signals output from the first and second push-pull signal detectors; And And a wobble generator for detecting a wobble signal by passing only a frequency component of a specific band from the push-pull signal synthesized by the synthesized signal generator. The method of claim 1, And the optical recording medium is an optical recording medium which can be repeatedly recorded. The method of claim 1, wherein the first push-pull signal detector And the input signal is sampled in a read power section instead of the erase power section when the optical recording medium is an optical recording medium capable of recording once. The method of claim 1, wherein the second push-pull signal detector And the input signal is held in a read power section instead of the erase power section when the optical recording medium is an optical recording medium capable of recording once. The method of claim 1, And an A / D converter configured to digitize the wobble signal detected by the wobble generator. The method of claim 1, wherein the first push-pull signal detector In the erasure power section, the electrical signals A, B, C, and D output from the optical pickup are sampled in the erasure power section, and the sampled electrical signal A, in the recording power section. A first sample & hold section for holding B, C, and D, A first gain control unit for adjusting the gains of the A and D signals that are sampled and held by the first sample & hold unit, respectively, and then adding the two signals and outputting the two signals; A second gain controller configured to adjust the gains of the B and C signals that are sampled and held by the first sample & hold unit, respectively, and then add and output two signals; A wobble comprising: a first differential signal generator for outputting a difference between the A + D signal gained and adjusted by the first gain controller and the B + C signal gained and adjusted by the second gain controller; Signal detection device. The method of claim 1, wherein the second push-pull signal detector In the recording power section, the electrical signals A, B, C, and D output from the optical pickup are sampled in the recording power section, and in the erase power section, the sampled electrical signals A, A second sample & hold section for holding B, C, and D, A third gain control unit for adjusting the gains of the A and D signals that are sampled and held by the second sample & hold unit, respectively, and then adding the two signals and outputting the two signals; A fourth gain controller configured to adjust the gains of the B and C signals that are sampled and held by the second sample & hold unit, respectively, and then add and output two signals; And a second differential signal generator configured to output a difference between the A + D signal gained and adjusted by the third gain controller and the B + C signal gained and adjusted by the fourth gain controller. Signal detection device. The method of claim 1, wherein the synthesized signal generation unit When recording by a control signal, the first push-pull signal output from the first push-pull signal detector and the second push-pull signal output from the second push-pull signal detector are synthesized and output for wobble detection. The first wobble signal detecting unit outputs only the first push-pull signal for wobble detection, characterized in that for outputting. The method of claim 1, When the synthesized signal generator combines the first push-pull signal and the second push-pull signal, a hold section of a predetermined section is generated between the sample of the recording power section and the sample signal of the erase power section in the synthesized sample & hold signal. And the wobble generator does not detect a wobble signal in the hold period. A wobble signal detection method of an optical recording and reproducing system for performing data recording and reproducing using multi-pulse power on a recordable optical recording medium which is divided into a land and a groove track and in which a wobble signal is recorded on any one of the tracks. To (a) detecting the amount of reflected light from the optical recording medium and outputting an electrical signal proportional thereto; (b) When the data is recorded, the electrical signal output in step (a) is sampled in the erasure power section, held in the recording power section, and then gain adjustment is performed on the sampled & held signal to obtain the first push-pull signal. Detecting; (c) sampling the electrical signal output in the step (a) during data recording and holding in the erasing power section, and then adjusting the gain of the sampled & held signal to detect the second push-pull signal. step; (d) synthesizing the first and second push-pull signals; And (e) detecting a wobble signal by passing only a frequency component of a specific band from the push-pull signal synthesized in step (d). The method of claim 10, The method further comprises the step of digitizing the wobble signal detected in the step (e). The method of claim 10, Step (b) increases the gain of the first sampled & held signal, and step (c) decreases the gain of the second sampled & held signal to adjust the levels of the two sampled & held signals. Wobble signal detection method. The method of claim 10, When the first push-pull signal and the second push-pull signal are synthesized in the step (d), a hold section of a predetermined section is generated between the sample of the recording power section and the sample signal of the erase power section in the synthesized sample & hold signal. And, in the step (e), the wobble signal detection method does not detect the wobble signal in the hold period.