KR19990079344A - Header section detection device - Google Patents

Abstract

An improved header section detection apparatus for preventing detection of false header information by using wobble information of a disc.

In the header section detection apparatus according to the present invention, a track having a wobble of a predetermined frequency component is formed, and each track records header information from a disk including sectors having a header information area distinguished from other areas by an envelope of a recording signal. A header section detection apparatus for detecting a section, comprising: a header envelope extractor for generating a header section signal indicating a section in which an envelope of an RF signal provided by a pickup device is larger than an envelope corresponding to the header information region; A header window signal generator for generating a header window signal indicating a section in which header information is valid based on a wobble signal included in an RF signal; And a header section information extractor for determining whether the header section signal is valid based on the header window signal and outputting a valid header section signal.

Since the header section detection apparatus according to the present invention re-verifies the header section signal generated by the envelope detection based on the wobble signal, only the valid header section signal can be detected, thereby enabling stable system control.

Description

Header section detection device

According to the present invention, a track having a wobble of a predetermined frequency component is formed, and each track detects a section in which header information is recorded from a disc composed of sectors having a header information area distinguished from other areas by an envelope of a recording signal. More particularly, the present invention relates to an improved header section detecting apparatus for preventing detection of false header information using wobble information of a disc.

In a disc such as a DVD or a DVD-RAM, information is recorded in sector units. Each sector consists of a header information area 10 and a user data area 12 having physical address information largely as shown in FIG. Accordingly, the RF signal read through the pickup is separated into a system processing header information and a system processing user data.

2A and 2B are diagrams for showing a form in which header information is recorded in a DVD-RAM disc. FIG. 2A shows the header information recorded in the first sector of the track, that is, the point where the land / groove is switched, and FIG. 2B shows the header information formed in the other sectors.

2A and 2B, reference numeral 20 is a header information area, and 22 is a user data area in which user data is recorded. The header information area 20 is further divided into a peak header area 20a and a bottom header area 20b, and the user data area 22 is divided into a land and a groove area.

When the disc is cut in the radial direction, the ridges and valleys are repeated like sine waves, and the floors correspond to lands, and the valleys correspond to grooves. That is, the tracks formed on the disc are divided into convex tracks (lands) and concave tracks (grooves).

In a DVD-RAM disc, the track is formed in a spiral form and the track is moved at a predetermined reference point. Typically this reference point is the first sector of the track.

Referring to FIG. 2A, track movement occurs in the first sector. The header information of the first sector is positioned so that a peak header occurs first when the next track is a land, and a bottom header occurs first when the next track is a groove. This is to recognize whether the next track is land or groove.

That is, a land / groove switching signal indicating switching to the land track or switching to the groove track can be generated according to the order of occurrence of the peak header area 20a and the bottom header area 20b.

Since the phase of the tracking error signal in the land and groove changes by 180 °, the disc reproducing apparatus selects the polarity (phase) of the tracking error signal in accordance with the land / groove switching signal.

The wobble exists in the user data area 22. The wobble refers to the wavy form formed between the land and the grooves in Figs. 2A and 2B, that is, the side walls of the tracks (land and groove) are curved.

When a signal recorded on a track is read by a pickup device (not shown), a low frequency signal corresponding to the curved frequency (frequency) of the wobble appears superimposed on the RF signal. This low frequency signal is called a wobble signal, and the wobble signal has a predetermined frequency in accordance with the DVD standard. The channel clock frequency of the DVD is 29.16 MHz and the frequency of the wobble signal is 0.156774 MHz divided by 186.

Since the wobble signal must have a prescribed frequency, the rotation speed of the disc can be controlled by comparing the disc with the frequency of the detected wobble signal and the reference clock for motor control. That is, the wobble has information about the reference clock for motor control and the channel clock for data reproduction.

As shown in FIGS. 2A and 2B, it is understood that the wobble is not formed in the header information area 20. This is because the header information is divided into a peak header and a bottom header as described above, and the peak header and the bottom header are recorded on the track boundary.

Therefore, an area such as a buffer / gap / guard is inserted between the header area and the data area to ensure that data is recorded at the correct position.

3 is a block diagram showing the configuration of a conventional header section detection apparatus. The apparatus shown in FIG. 3 includes a pickup 302, an RF AMP (Radio Frequency AMP) 303, an offset remover 304, an EFM (Eight to Fifteen Modulation) comparator 306, an EFM PLL 307, a header envelope An extractor 305, an AM detector, and a header segment extractor 308.

The operation of the apparatus shown in FIG. 3 is as follows. The RF signal output through the disk 301, the pickup 302, and the RF AMP 303 is provided to the offset remover 304. The offset remover 304 removes the offset based on the midpoint of the EFM signal regardless of the header information section and the user data section. The offset-free EFM signal is binarized through the EFM comparator 306.

4 is a block diagram showing a detailed configuration of the EFM comparator 306 shown in FIG. The EFM comparator 306 shown in FIG. 4 includes a first comparator 40, a low pass filter 42, a differential amplifier 44, and a gain determiner 46. Here, the low pass filter 42 has a characteristic corresponding to double speed.

The first comparator 40 compares the slice level Vp determined based on the EFM signal provided thereto and the binarized EFM signal EFMS, and outputs the binarized EFM signal EFMS according to the result. That is, when the EFM signal provided from the offset eliminator 304 is equal to or larger than the slice level Vp, "1" is output, and conversely, "0" is output.

The low pass filter 42 low pass filters the EFMS signal to obtain its average level. Here, the filtering characteristic of the low pass filter 42 depends on the double speed. This is because the magnitude and frequency of the EFM signal vary depending on the playback speed of the disc 301.

The differential amplifier 44 amplifies the difference between the output of the low pass filter 42 and the predetermined reference voltage Vref. Here, the predetermined reference voltage Vref represents the slice level when there is no offset. The output of the differential amplifier 44 is provided to the first comparator 40 as slice level Vp.

The gain determiner 44 adaptively determines the gain of the differential amplifier 44 according to the value of the slice level Vp.

The EFMS signal output from the EFM comparator 306 is input to the EFM PLL 307.

The EFM PLL 307 outputs the channel clock PLCK phase-locked to the EFMS signal and the data EFML reproduced by the channel clock PLCK. Here, the PLCK has a frequency of 29.16 MHz as the channel clock signal of the DVD.

Meanwhile, the RF signal is also provided to the header envelope extractor 305.

The header envelope extractor 305 outputs a HEADPK signal indicating a section of a peak header and a HEADBT signal indicating a section of a bottom header from the RF signal provided from the RF AMP 303. Since the peak header has a higher peak value than the average peak level of the RF signal, and the bottom header has a low peak value, the peak header generates a HEADPK (HEAD PeaK) signal and a HEADBT (HEAD BuTtom) signal. Here, the standing time of the HEADPK signal and the HEADBT signal is almost identical to the standing time of the actual peak header and the bottom header, but the falling time is later than the falling time of the actual peak header and the bottom header. This is because the HEADPK signal and the HEADBT signal are usually generated by the integration method.

The HEADPK signal and the HEADBT signal extracted by the header envelope extractor 305 are input to the AM detector and the header section information extractor 308.

The AM detector and header section information extractor 308 generates an AMDET signal having a specific pattern using PLCK and EFML provided from the EFM PLL 307. The HEADPK, the HEADBT, and the PLCK are used to generate HDPK (HDad PeaK) and HDBT (HeaD BuTtom) signals indicating the correct peak header and bottom header sections, and output HD_DEL signals by oring them.

The system controller (not shown) performs address information extraction and servo control by using the AMDET, HDPK, HDBT, and HD_DEL signals generated by the AM detector and the header section information extractor 308.

Therefore, the signals AMDET, HDPK, HDBT, and HD_DEL output from the AM detector and the header section information extractor 308 are not only important for extracting address information on the disk but also for focus servo and tracking servo. It is also important for tracking polarity control, which requires switching between lands and grooves.

The header envelope extractor 305 may output the HEADPK and HEADBT signals even in a region other than the actual header region due to anxiety of tracking control.

However, the apparatus shown in FIG. 3 has no protection against this, and thus, the AM detector and the HEADER section information extractor 308 may generate false AMDET, HDPK, HDBT, and HD_DEL signals based on the wrong HEADPK and HEADBT signals.

If the wrong header section information is outputted, the servo system has a lot of unnecessary focusing and tracking hold, which not only degrades the overall system performance, but also decisively determines the land / groove determination signal required for the tracking servo system. Cause. Here, the tracking hold refers to maintaining the previous tracking value in the header section.

An object of the present invention is to provide a header section detection device that outputs an accurate header section signal, which is devised to solve the above problems.

1 is for showing the sector structure of a disc.

2A to 2B are diagrams for showing a form in which header information is recorded on a DVD disc.

3 is a block diagram showing the configuration of a conventional header section detection apparatus.

4 is a block diagram showing a detailed configuration of the EFM comparator shown in FIG.

5 is a block diagram showing the configuration of a header section detection apparatus according to the present invention.

Figure 6 is shown to show the relationship between the sector and the wobble signal.

7 is a block diagram showing the configuration of a preferred embodiment of a header section detection apparatus according to the present invention.

8A to 8C are waveform diagrams for showing a relationship between an RF signal, an EFM signal, and header section signals.

9 is a block diagram showing a detailed configuration of the EFM comparator shown in FIG.

FIG. 10 is a block diagram illustrating a detailed configuration of the wobble slicer shown in FIG. 7.

FIG. 11 is a block diagram showing a detailed configuration of the wobble reproduction PLL shown in FIG.

FIG. 12 is a waveform diagram illustrating operations of the wobble counter, the AM detection, and the HEAD section information extractor shown in FIG. 7.

The header section detection apparatus according to the present invention to achieve the above object

A track having a wobble of a predetermined frequency component is formed, wherein each track detects a section in which the header information is recorded from a disc composed of sectors having a header information area distinguished from other areas by an envelope of a recording signal. To

A header envelope extractor for generating a header section signal indicating a section in which an envelope of the RF signal provided by the pickup apparatus is larger than an envelope corresponding to the header information area;

A header window signal generator for generating a header window signal indicating a section in which header information is valid based on a wobble signal included in an RF signal; And

And a header section information extractor for determining whether the header section signal is valid based on the header window signal and outputting a valid header section signal. Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

5 is a block diagram showing the configuration of a header section detection apparatus according to the present invention. The apparatus shown in FIG. 5 includes a header envelope extractor 50, a header window signal generator 54, and a header section information extractor 56.

The header envelope extractor 50 generates a header section signal indicating a section in which header information exists from an RF signal provided from a pickup device (not shown). The header section signal is divided into a peak header section signal HEADPK and a bottom header section signal HEADBT. The header envelope extractor 50 generates a peak header section signal and a bottom header section signal by determining the envelope of the RF signal. Specifically, since the peak header has a higher peak value than the average peak level of the RF signal, and the bottom header has a low peak value, the peak header generates a HEADPK signal and a HEADBT signal by using the peak header.

The wobble signal is obtained from the RF signal. When a signal recorded on a track is read by a pickup device (not shown), a low frequency signal corresponding to the frequency of the wobble formed on the track is superimposed on the RF signal. Thus, a wobble signal can be obtained by low pass filtering the RF signal. Although the wobble signal may be generated in the RF AMP, a wobble signal reproducing apparatus may be separately provided to reproduce only the wobble signal from the RF signal.

The wobble signal has a constant correlation with the clock frequency. For example, the channel clock frequency of the DVD is 29.16 MHz and the frequency of the wobble signal is 0.156774 MHz divided by 186.

Figure 6 is shown to show the relationship between the sector and the wobble signal. As described in FIG. 1, a sector is largely composed of a header 60 and main data 72. A sector has a size of 2697 bytes, of which header information occupies 128 bytes and main data occupies 2418 bytes. The header 60 is composed of a peak header 60a and a bottom header 60b.

Other mirror region 62, gap region 64, first guide region 66, VFO region 68, PS region 70, PA3 region 74, second guide region 76, buffer region ( 78).

The mirror / gap / guard / buffer areas 62, 64, 66, 76, and 78 are for ensuring that data is recorded at the correct position, and the VFO area 68 provides the channel clocks necessary for the reproduction of the physical address and data. It is provided to play quickly.

16 channel clock (PCLK) per byte, so header area 60, mirror area 62, gap area 64, first guide area 66, VFO area 68, PS area 70, main data area 2048, 32, 160, 320, 560, 48, 38688, 16 880, 400 channel clocks are allocated to the 72, PA3 region 74, second guide region 76, and buffer region 78 for each section. . A channel clock of 1025 is allocated to each of the peak header 60a and the bottom header 60b.

In addition, the header area 60, the mirror area 62, the gap area 64, the first guide area 66, the VFO area 68, the PS area 70, the main data area 72, and the PA3 area ( 74, 11, 0.2, 0.86, 1.72, 3, 0.26, 208, 0.09, 4.73, and 2.15 cycles are allocated to the wobble signals for each section of the second guide region 76 and the buffer region 78, respectively. 5.5 cycles are allocated to each of the peak header 60a and the bottom header 60b.

As shown in Fig. 6, the HEADPK signal starts at the start position of the peak header, but the end position is longer than the end position of the peak header. In contrast, it can be seen that the HDPK signal exactly matches the peak header. The same is true for HEADBT and HDBT. The HD_DEL signal is the sum of the HDPK and the HDBT. The HD_DEL signal is obtained by these operations and coincides with the header information section. Fig. 6 relates to the sector of the land area, and the positions of the peak header and the bottom header are reversed in the groove area.

The header window signal generator 54 generates a header window signal indicating a section in which header information is valid based on the wobble signal. That is, as shown in FIG. 6, the header window signal is generated for every sector by using the position of the header information for 11 cycles of the wobble signal from the start position of the sector. This hair window signal starts a few wobble clocks before the start of the header section and ends a few wobble clocks later than the end of the header section.

The header section information extractor 56 determines whether the header section signal is valid based on the header window signal. That is, if the header section signal is generated within the header window signal by performing an AND operation on the header section signal and the header window signal, the header section signal is output as a valid one, and otherwise not output. In addition, if an AM signal is generated while the result of the AND operation is valid, a monitor signal indicating that disc reproduction is normal is further output.

7 is a block diagram showing the configuration of a preferred embodiment of a header section detection apparatus according to the present invention. The apparatus shown in FIG. 7 includes a pickup 702, an RF AMP 703, an offset remover 704, an EFM comparator 706, an EFM PLL 707, a header envelope extractor 705, an AM detector, and a header segment extractor. 708, wobble slicer 709, wobble regeneration PLL 710, and wobble counter 711.

The operation of the apparatus shown in FIG. 7 will be described in detail with reference to the accompanying drawings.

The RF signal output through the disk 701, the pickup 702, and the RF AMP 703 is canceled by the offset remover 704.

In the conventional apparatus shown in FIG. 3, the EFM comparator 306 performing binarization corrects the offset of the input signal EFM by receiving the binarized EFM signal EFMS without discriminating the header information area and the user data area. In contrast, the apparatus shown in FIG. 7 is designed to differently correct offsets of the PEAK part and the BOTTOM part of the header by the HDPK and HDBT signals generated by the AM detector and the HEADER section information extractor 408.

As shown in FIG. 8, the PEAK and BOTTOM portions of the HEADER are designed to correct an error caused by not completely removing the offset.

8A to 8C are waveform diagrams for showing a relationship between an RF signal, an EFM signal, and header section signals. As shown in FIG. 8A, the RF signal is largely composed of a peak header portion 80, a bottom header portion 82, and a user data portion 84. The peak header portion 80 has a similar peak-peak value but a larger envelope than the user data portion 84, and the bottom header portion 82 shows a similar peak-peak value but a smaller envelope than the user data portion 84. Able to know.

The waveform after the RF signal shown in FIG. 8A passes through the offset remover 704 is shown in FIG. 8B. As can be seen in FIG. 8B, it can be seen that the peak header portion 80 and the bottom header portion 82 are harder to identify than those shown in FIG. 8A. This is because the offset eliminator 704 performs offset elimination without covering the header portions 80 and 82 and the user data portion 84. Accordingly, the peak header portion 80 is preferably compensated by the offset 1 to further increase the envelope, and the bottom header portion 82 is preferably compensated by the offset 2 to further lower the envelope. This compensation is done in the EFM comparator 706.

9 is a block diagram showing a detailed configuration of the EFM comparator 706 shown in FIG. The EFM comparator 706 shown in FIG. 6 includes a differential amplifier 90, a low pass filter 92, a first comparator 94, an adder 96, a switch 98, an offset generator 100, 102, Multiplexer 104, and second comparator 106.

The differential amplifier 90 amplifies and outputs a difference between the slice level Vp determined based on the EFM signal provided thereto and the fed back EFM signal.

The first comparator 94 compares the output of the differential amplifier 90 with a predetermined reference voltage Vref and provides a binarized output according to the result. That is, when the output of the differential amplifier 90 is equal to or greater than the reference voltage Vref, "1" is output, and conversely, "0" is output. An output of the first comparator 94 is provided to the low pass filter 92.

The low pass filter 82 low pass filters the output of the first comparator 94 to obtain its average level and provides it to the differential amplifier 90. Here, the filtering characteristic of the low pass filter 82 depends on the double speed. This is because the magnitude and frequency of the EFM signal vary depending on the playback speed of the disc 701. In addition, since the output of the low pass filter 92 is provided to the differential amplifier 90, there is a quick response in applying the slice level.

The offset generators 100 and 102 generate a first offset OFFSET1 and a second offset OFFSET2. Here, the first offset OFFSET1 is an offset value for compensating the peak header signal as shown in FIG. 8B, and the second offset OFFSET2 is an offset value for compensating the bottom header signal. These offset values correspond to the difference between the center value of the EFM signal in the data area and the center value of the EFM signal in the peak header and bottom header areas, and can be obtained according to the DVD standard.

The multiplexer 104 selects and outputs one of the first offset OFFSET1 and the second offset OFFSET2 according to the HDPK and the HDBT. That is, the first offset OFFSET1 is selected and output in the section where the HDPK is valid, and the second offset OFFSET2 is selected and output in the section where the HDBT is valid. Here, HDPK and HDBT are signals output from the AM detector and header section extractor 708 of FIG. 7.

The adder 96 adds and outputs the first offset OFFSET1 or the second offset OFFSET2 provided from the multiplexer 104 to the EFM signal output from the differential amplifier 90.

The second comparator 106 compares the offset-free EFM signal with a predetermined reference level Vref and outputs the result as a binarized EFM signal EFMS.

The switch 98 provides the selector 96 with the selective output of the multiplexer 104 in the header section and is driven by the HD_DEL signal output from the AM detector and header section extractor 708 of FIG.

The binarized signal EFMS is subjected to phase synchronization in the EFM PLL 707 to obtain data EFML synchronized with the clock synchronously coupled to the AM detector and the HEADER interval information extractor 708.

In addition, the header envelope is extracted by the header envelope detector 705, and the extracted HEADPK and HEADBT signals are input to the AM detector and the HEADER section information extractor 708.

AM detector and HEADER section information extractor 708 receives header window signals in addition to these HEADPK and HEADBT signals to protect HDPK, which is the PEAK part signal of HEADER, and HDBT, which is the BOTTOM part of HEADER, and the AM signal is generated within this header section information. AM detection is performed according to whether or not it is used, and only AM generated within the header section is used as valid.

If the AM signal occurs in the header section, the AMLOCK signal indicates that the current state is normal. Thus, to perform this function, the WOBBLE signal reproduced from the disc is binarized and a PLL is performed on the binarized wobble signal to create a new wobble signal.

FIG. 10 is a block diagram illustrating a detailed configuration of the wobble slicer 709 shown in FIG. 7. The wobble slicer 709 shown in FIG. 10 includes a midpoint detection circuit 120 and a comparator 122.

The midpoint detection circuit 120 detects the center value of the wobble signal WOBBLE provided by the RF AMP 703 and provides it as the slice level of the comparator 122. The comparator 122 compares the wobble signal WOBBLE and the slice level to generate a binarized wobble signal WOBBLE_D.

11 is a block diagram showing a detailed configuration of the wobble reproduction PLL 710 shown in FIG. The wobble regeneration PLL 710 illustrated in FIG. 11 includes a phase difference detector 110, a charge pump 112, a voltage controlled oscillator 114, and a divider 116. It depends on the general PLL configuration. The wobble regeneration PLL 710 generates a wobble clock WBCK synchronized with the binarized wobble signal WOBBLE_D. This wobble clock WBCK has a frequency of 0.156774 MHz, divided by 186, the DVD's channel clock frequency of 29.16 MHz.

The wobble counter 711 counts the wobble clock WBCK generated in the wobble regeneration PLL 710.

In the header section information WBHD using the header window HDWIN and the wobble signal WOBBLE, a total of 232 wobble signals are input between the actual header and the header, that is, per sector, as shown in FIGS. 8 and 6. Using this, the wobble counter 711 generates the wobble header signal WBHD and the header window signal HDWIN as shown in FIG. 12. Here, the wobble header signal WBHD is a reference signal for generating the header window signal HDWIN.

For example, when the count value of the wobble counter 711 is 231 to 11, the header window signal HDWIN is generated, and when the count value is 0 to 11, the wobble header signal WBHD is generated.

The wobble counter 711 is reset (by / RST) on the rising edge of the header section signal HD_DEL generated by the AM detector and the HEADER section information extractor 708 to match the synchronization of the wobble count value with the header actually generated.

The AM detector and the HEADER section information extractor 708 are extracted from the envelope detector 705 by the wobble header signal WBHD and the header window signal HDWIN generated by the wobble counter 711, and verify and verify the extracted HEADPK and HEADBT signals. According to the result, the correct AMDET, HDPK, HDBT, and HD_DEL signals are generated.

Operations of the AM detector and the HEADER section information extractor 708 will be described in detail with reference to FIG. 12.

FIG. 12 is a waveform diagram illustrating operations of the wobble counter 711, the AM detector, and the HEADER section information extractor 708 shown in FIG. The waveform diagram shown at the top of FIG. 12 shows an RF signal including header information. The hatched portion in the middle shows a state in which the header information is not normally reproduced due to a tracking error or the like.

In response, erroneous HEADPK and HEADBT occur and are shown as solid lines in the middle in the second and third waveform diagrams.

The fourth figure shows the header window signal, and the fifth and sixth show the HEPK and HDBT verified by the header window signal HDWIN shown in the third. It can be seen that erroneous header interval signals shown by solid lines in the second and third are removed.

The sixth one shows the header interval signal HD_DEL, which corresponds to the calculation of HEPK and HDBT shown in the fourth and fifth.

Shown in the seventh and eighth are the wobble header signal WBHD and the header window signal HDWIN, respectively.

The ninth one is AMDET indicating whether or not a valid AM signal is detected, and the tenth one is AMLOCK, which is a monitor signal indicating that the disc is being played normally.

By this operation, the AM detector and the header section information extractor 708 not only protect the header section information by filtering out the wrong header PEAK / BOTTOM signal that may occur due to disk damage, etc. When it occurs, it is judged to be normal and as a result, stable system control is possible.

As described above, the header section detection apparatus according to the present invention has the effect of enabling stable system control by revalidating the header section signal generated by envelope detection based on the wobble signal so that only valid header section signals can be detected. .

Claims (14)

A track having a wobble of a predetermined frequency component is formed, wherein each track detects a section in which the header information is recorded from a disc composed of sectors having a header information area distinguished from other areas by an envelope of a recording signal. To A header envelope extractor for generating a header section signal indicating a section in which an envelope of the RF signal provided by the pickup apparatus is larger than an envelope corresponding to the header information area; A header window signal generator for generating a header window signal indicating a section in which header information is valid based on a wobble signal included in an RF signal; And And a header section information extractor for determining whether the header section signal is valid based on the header window signal and outputting a valid header section signal. The method of claim 1, wherein the header window signal generator A counter for counting the wobble signal; And a window generator for generating a header window signal indicating a start position to an end position of the header information based on the count output of the counter. The method of claim 1, A wobble slicer for binarizing the wobble signal and providing the wobble signal to the header window generator, And the header window signal generator generates a header window signal indicating a section in which header information is valid based on the binarized wobble signal generated by the wobble slicer. The method of claim 3, wherein the header window signal generator A counter for counting the binarized wobble signal; And a window generator for generating a header window signal indicating a start position to an end position of the header information based on the count output of the counter. 4. The apparatus of claim 3, further comprising a wobble regeneration phase locked loop for generating a wobble clock signal synchronized with the binarized wobble signal generated by the wobble slicer and providing the wobble clock signal to the header window signal generator. And the header window signal generator generates a header window signal indicating a section in which header information is valid based on a wobble clock signal provided in the wobble regeneration phase locked loop. The method of claim 5, wherein the header window signal generator A counter for counting the wobble clock signal; And a window generator for generating a header window signal indicating a start position to an end position of the header information based on the count output of the counter. 2. The apparatus of claim 1, further comprising: an EFM comparator for binarizing the RF signal; And an EFM phase locked loop for reproducing a channel clock signal synchronized with the binarized EFM signal provided by the EFM comparator, And the header section information extractor generates a header section signal synchronized with a channel clock signal provided in the EFM phase locked loop. The method of claim 7, wherein the EFM comparator A differential amplifier for amplifying the difference between the RF signal and the fed back signal; A first comparator for comparing the output of the differential amplifier with a predetermined reference value; A low pass filter for low pass filtering the comparison output of the first comparator and providing it as a signal fed back to the differential amplifier; And And a second comparator for comparing the output of the differential amplifier with the predetermined reference value. 9. The header section signal generator of claim 8, wherein the low pass filter has a characteristic that depends on the playback speed of the disc. The method of claim 8, wherein the offset controller is An offset generator having an offset value of the header information; And an adder which adds an offset value generated by the offset generator and an output of the differential amplifier and provides the second comparator to the second comparator. The method of claim 10, The offset generator includes a first offset generator having an offset value of a peak header and a second offset generator having an offset value of a bottom header, In the peak header section, a first offset value generated by the first offset generator is selected, and in the bottom header section, a multiplexer that selects and provides a second offset value generated by the second offset generator to the adder is provided. Header section signal generator characterized in that it further comprises. The method of claim 11, And a switch configured to provide a selector of the multiplexer to the adder in a header section. The method of claim 1, wherein the header validity interval discriminator And an AND operator for ANDing the header section signal and the header window signal. The method of claim 13, wherein the header validity interval discriminator And outputting a monitor signal indicating that disc reproduction is normal when an AM signal is generated while the output of the AND operator is valid.