• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to an apparatus for reproducing information from a recording medium. The apparatus includes a read head 6 for reading a plurality of marks representing information from tracks on a disc-shaped recording medium 4. Moreover, in response to the control signal cs1, there are A / D converters 12 and 34 for A / D converting the read signal using a specific clock frequency f s . In addition, a bit recovery unit 130 having an input connected to the A / D conversion means is provided, which is a sequence consisting of a plurality of bits from a signal applied to its input using a specific bit frequency f b . It is configured to retrieve. In addition to the generator for deriving the control signal, there is also a generator for deriving the specific bit frequency. The generation unit for deriving the control signal derives a control signal indicating the relative speed of the read head with respect to the plurality of marks from the read signal, and is independent of the relative speed of the at least one read head with respect to the plurality of marks. Means (132; 134, 84) for generating a specific clock frequency (f s ) for outputting approximately N samples per bit by the / D conversion means (12, 34).
    公开号:KR20010014250A
    申请号:KR1019997012357
    申请日:1999-04-20
    公开日:2001-02-26
    发明作者:반덴엔덴규스베르트제이.
    申请人:요트.게.아. 롤페즈；코닌클리케 필립스 일렉트로닉스 엔.브이.；
    IPC主号:
    专利说明:

    A device for reproducing information from a recording medium {APPARATUS FOR REPRODUCING INFORMATION FROM A RECORD CARRIER}
    The present invention relates to an apparatus for reproducing information from a recording medium. Such devices are known. See US Patent Specification 5,569,912, which is Document D1 in the list of related documents described at the end of this specification.
    The above apparatus is for reading an optical disc, such as a CD or a DVD, or for reading and recording a recordable record carrier. In such an apparatus, the read head generates a read signal from the track on the record carrier, while the head moves with respect to the track at a certain speed. The recording medium is configured to rotate with a nominal speed inversely proportional to the radial position of the read head so that the information signal can be recovered from the recording medium having a constant density at a substantially constant bit rate during the reproduction process. When information is retrieved from different parts of the disc, the read head moves radially at high speed, which is called a jump, and the rotational speed must be correspondingly modified to obtain the above-mentioned specific speed. Changes in rotation speed create delays and require powerful motors.
    As a result, the present invention provides a reproducing apparatus that is more versatile and that can read information from a recording medium at various speeds.
    According to the present invention, a reproducing apparatus for reproducing information from a recording medium comprising a sequence consisting of a plurality of bits represented by a plurality of marks in a track on a recording medium,
    Reading means having a read head for reading a plurality of marks from the track and generating a read signal from said track,
    A / D conversion means for A / D converting the read signal using a specific clock frequency in response to the first control signal;
    Bit detection means having an input connected to the A / D conversion means and configured to retrieve a sequence consisting of a plurality of bits from a signal given to its input using a particular bit frequency and means for deriving the particular bit frequency;
    Output means for supplying a sequence consisting of a plurality of bits,
    -Derivation means for deriving said first control signal,
    And the derivation means comprises means for deriving a second control signal representing the relative speed of the read head relative to the plurality of marks from the read signal, and means for outputting the first control signal in dependence on the second control signal. do.
    The present invention has the effect that another digital element, such as an A / D converter and equalizer and bit detection means, operates at a substantially constant ratio between a particular clock frequency and a bit frequency. Since the parameter inside the read signal corresponds to the actual speed of the read head in the plurality of recorded marks, it is advantageous to derive the first control signal from the speed dependent parameter of the read signal itself. Such a configuration results in the desired reconstruction of the bit frequency over a wide range of speeds, thus allowing for quick initiation of data reconstruction after the jump.
    Moreover, the invention has the advantage that the rotational speed can be deformed more slowly, so that the requirements on the drive motor and the power consumption due to the acceleration and braking of the disc become less stringent. When a jump is performed with a short time interval, the device operates effectively at a substantially constant rotational speed (Constant Angular Velocity, CAV), while the rotational speed is CLV speed when a relatively large amount of data is read. Because the device slowly deforms over the range, ie inversely proportional to the radial position of the read head, the device operates at a constant constant linear velocity (CLV) of the head relative to the track. This configuration allows the device to adapt itself to the type of application, i.e. for short applications for many random jumps, and with a certain specific bit frequency when reproducing large amounts of information. Has the advantage.
    In a preferred embodiment, the derivation means further comprises means for deriving a third control signal having a relationship with the bit frequency, wherein the means for outputting the first control signal is dependent on the second control signal and the third control signal. It is characterized in that it is configured to output a control signal. This configuration allows the above ratio to be adjusted to almost a numerical value N. This is implemented by two control loops, one coarse control loop and a fine control loop. This approximate control loop generates a second control signal and is described above such that the A / D converter outputs a substantially constant number of N samples per bit to be detected regardless of the relative speed of the readhead relative to the track. To control. The fine control loop generates a third control signal and controls the specific clock frequency to correct a deviation of the specific clock frequency expressed in samples per bit from the value of N samples per bit.
    As a result, even if the means for deriving the particular bit frequency described above has a small capture range, the device controls very quickly so that it has a state of N number of samples per bit.
    Such and other inventions of the present invention will become more apparent from the embodiments set forth below with reference to the accompanying drawings in which:
    1 and 2 show an embodiment of the device,
    3 illustrates one embodiment of the apparatus in more detail,
    4 shows the addition of an output buffer for the device shown in FIG. 3,
    FIG. 5 shows another embodiment of the A / D converter inside the apparatus shown in FIG. 1, 2 or 3, and FIG.
    6 shows an embodiment of an equalizer inside the device of FIG. 1, 2 or 3,
    Fig. 7 shows magnitude characteristics as a function of frequency of the information signal read out from the recording medium, for two different speeds of the recording medium during the reproduction process;
    8 shows the filter curve of the equalizer as a function of frequency for two similar speeds of the recording medium,
    9 shows the capture range of the phase-locked loop inside the apparatus shown in FIG.
    1 shows an embodiment of a playback apparatus according to the present invention. The apparatus includes a read head 6 for reading information from the recording medium 4 via a radiation beam 42 such as a laser beam guided through an optical system and outputting a plurality of marks in the track to the detector. The output of the read head 6 is connected to the input of the A / D converter 12, which has an output 14. This A / D converter samples the information read from the track on the record carrier 4 using a specific clock frequency (or sampling frequency) f s, and uses the specified clock frequency to sample a sample of the information signal. Supply to output 14. The recording medium 4 is rotated by the motor 48 controlled by the rotation control signal 46.
    The apparatus generally includes an equalizing section 16. However, this equalizer 16 is not essential to the description of the present invention and may be omitted or replaced by other digital signal processing means for restoring the information signal. The input of the equalizer 16 is connected to the output 14 of the A / D converter 12, and the output of the equalizer 16 is connected to the input of the bit recovery unit 130. The bit recovery unit 130 includes a generation circuit that generates a bit frequency f b like the PLL, and a bit detection unit. This bit detector is configured to retrieve a sequence consisting of a plurality of bits from the input signal using a specific bit frequency f b . The output 26 of the bit recovery unit 130 is connected to an output unit 101 that controls the output of data. The output unit 101 controls the rotational speed of the motor 48 through the rotation control signal 46, and controls the position of the read head via the control signal 56 so that the required amount of data is retrieved. If no data is needed, the read head is controlled to jump back by one or more tracks.
    The apparatus comprises speed derivation means 132 for deriving a second control signal cs2 representing the relative speed of the read head relative to a plurality of marks on the record carrier 4 representing the information signal from the information signal read out from the record carrier. It is further provided. The rate may be derived from specific frequency components in the spectrum of the read signal. For a recording medium having a plurality of marks whose marks have different lengths, the speed deriving means 132 is dependent on the average length of the signal portion inside the information signal corresponding to the mark, according to the second control signal cs2. It is configured to derive. For example, in the known CD, a channel code called EFM having a run length of 3 to 11 and an average run length of 5 is used. Similar channel codes are used for DVD. The average run length corresponds to the appropriate indicator of the above speed. Alternatively, the longest and / or shortest marks can be identified in the read signal, and each length or their difference can be used as an indicator of speed. The second control signal cs2 is converted to the control signal cs1 and connected to the f s generator 34 which may be a voltage controlled oscillator (VCO) to generate a specific clock frequency f s . The control signal cs2 described above is combined with the third control signal cs3 given by the bit recovery unit 130 through the combining unit 84 to output the first control signal. The third control signal indicates the deviation of the number of samples per bit from the target value of the number of samples per bit.
    2 shows another embodiment of a playback apparatus according to the present invention. Similarly to the embodiment described above with reference to FIG. 1, the apparatus includes a motor 48, a read head 6, an A / D converter 12, a bit recovery unit 130, an output unit 101, and f s. Generator 34 and optional equalizer 16 and / or synthesizer 84 are provided. As another embodiment of the speed derivation means, the apparatus comprises a second control signal cs2 representing the relative speed of the read head relative to a plurality of servo tracks in the track on the record carrier 4 from the signal read out from the record carrier. A distance derivation means 134 for deriving is further provided. These servo marks are either detected by the read signal itself or are derived from the read head through a combination of different detection signals, for example from a quadrant detector which is generally used to derive the servo signal. The above-described detection signal or servo signal is connected to the input of the distance derivation means after the analog form or the digitization. From these servo signals, the time interval between the plurality of servo marks is determined by the distance derivation means 134. The speed value is based on the known distance of the servo mark on each type of recording medium and the measured time interval, which is converted into the control signal cs2. The control signal cs2 described above is output to the synthesizing means 84 and converted into the control signal cs1. At this time, an average of speed values is taken to prevent sudden fluctuations in the control signal. The shape of the servo mark depends on the respective recording medium. These servo marks may be at a radial change in track position, commonly called a wobble, and / or at a predetermined distance between the header and / or pre-pit and / or the plurality of marks described above. It may be a fine clock mark. Track wobble is most commonly used in CD-Rs, in particular modulation of the wobble is used to indicate address information. Headers are mainly used in data storage disks such as, for example, DVD-RAM, where the distance between the headers corresponds to a predetermined number of bits. Prepits are used in servo control or headers for recordable discs such as DVD-R, and likewise have a predetermined distance. A fine clock mark is a specific form of track change used in combination with a wobble, which is quite different from the wobble, i.e., the fine clock mark has a relatively high spatial frequency, while the rest of the wobble has a relatively low spatial frequency. In this case, the distance derivation means 134 has wobble detection means and means for detecting fine clock marks of different types. The number of bits between the plurality of servo marks likewise depends on the radial position on the disc. Thus, the actual number of bits is calculated by approximating a radial position indicator, such as a track number or area code, that can be retrieved from a header or modulated wobble. The distance driving means is configured to derive the second control signal cs2 depending on the parameters of the servo signal corresponding to the plurality of marks indicative of the distance.
    3 shows a detailed embodiment of the playback apparatus according to the present invention. The apparatus has a reading section 2 for reading information from the recording medium 4. This readout comprises at least one readhead 6 and generally a preamplifier 8. The output of the reading section 2 is connected to the input 10 of the A / D converter 12 having the output 14. The A / D converter 12 samples the information read from the track on the recording medium 4 using a specific clock frequency (or sampling) f s, and uses the specified clock frequency to generate a plurality of samples of the information signal. Is supplied to its output 14.
    The apparatus generally includes an equalizing section 16. However, this equalizer 16 is not essential to the description of the present invention and may be omitted or replaced by other digital signal processing means for restoring the information signal. The input 18 of the equalizer 16 is connected to the output 14 of the A / D converter 12, and the output of the equalizer 16 is connected to the input 22 of the bit detector 24. . The output 26 of the bit detector 24 is connected to the output terminal 28.
    The bit detector 24 described above is configured to retrieve a sequence consisting of a plurality of bits from a signal given to its input 22 using a specific bit frequency f b .
    The apparatus includes a generation circuit 30 for generating a bit frequency f b and a generation circuit 32 for generating a clock frequency f s . The generation circuit 30 includes a phase comparator 70, a loop filter 72, and a voltage controlled oscillator 74 as a phase synchronization loop. The first input of this phase comparator 70 is connected to the output of the equalizer 16, and the second input of the phase comparator 70 is connected to the output of the oscillator 74. The output of the phase comparator 70 is connected to the input of the loop filter 72, and the loop filter has an output connected to the input of the oscillator 74 via the signal combiner 76. The output of the oscillator 74 is further connected to the clock input of the bit detector 24.
    At this time, the above-described generator circuits 30 and 32 may be operated at frequencies f b and f s so that these generator circuits become f s / f b = N, regardless of the relative speed of the head 6 relative to the track on the recording medium to be read. Note that N is a constant, which is not necessarily an integer constant.
    This value N is detected by the bit detector 24 and represents the number of samples per bit generated by the A / D converter 12.
    The A / D converter 12 converts the information signal read out from the recording medium using the specific clock frequency f s described above in response to the first control signal cs1. In this embodiment, such a clock signal is generated by a voltage controlled oscillator 34 that corresponds to a portion of loop 32 and supplies a clock frequency f s to clock input 36 of A / D converter 12. . This clock frequency f s is also supplied to the clock input 80 and converter 82 of the equalizer 16. Converter (82) has the form of a frequency divider, divides a given frequency f s to its input by N and outputs a frequency f s / N for its output. This output is connected to another input of the signal combiner 76.
    A drive motor 48 is provided to rotate the disk-shaped recording medium 4 in the direction indicated by arrow 44. This motor is controlled by the control signal 46. The control signal 46 may be derived from a signal read by the read head based on a plurality of information marks or servo marks on the recording medium. Alternatively, the control signal 46 described above may be based, for example, on the amount of necessary data derived from the data buffer device as shown in FIG. The read head is placed in the radial direction by the radial control signal 56 generated in a conventional manner.
    The apparatus includes a converter 60 for generating the second control signal cs2 in response to the parameter of the read signal. As described with reference to Figs. 1 and 2, this second control signal cs2 measures the relative speed of the read head 6 with respect to a plurality of marks indicating information or servo information indicating the position of the track on the disc. Corresponds to the value. The second control signal cs2 is given to the input 82 of the signal synthesizing unit 84. Through the second input 86 of the combining section 84, the third control signal cs3 is given. The third control signal cs3 corresponds to the output signal of the loop filter 72 inside the PLL 30. The apparatus further comprises conversion means 50 for deriving a fourth control signal cs4 connected to the combining section 84. Motor 48 may have a taco generator that outputs taco pulses via line 58 toward transducer 50. The transducer 50 receives the position control signal 56, and the radial position and the rotational speed correspond to the measured values of the nominal relative speed of the read head relative to the recording medium at the rotational and radial positions described above. Converted to the value of the fourth control signal cs4. This nominal speed may be calculated from the actual measured rotational speed and the radial position, or may be set as a target value when jumping to another part of the track, the target value being the radial position upon arrival and / or Based on the speed of rotation. Similarly, the combining unit 84 is configured to output the first control signal by adding a signal to the second control signal cs2, for example, depending on the fourth control signal. Alternatively, the synthesizing unit 84 may not be able to use any information signal from the read head, or may be used in conditions of the device, such as a period of time when the read head moves radially across the track to access different parts of the track. Rely on to connect the fourth control signal instead of the second control signal.
    Hereinafter, the operation of the above apparatus will be described in more detail. In this case, it is assumed that the recording medium is driven at a specific rotational speed and radial position to generate the linear speed v 1 . As a result, a plurality of servo marks are detected and given to the transducer 60, which in turn generates the second control signal cs2. The second control signal cs2 is given to the oscillator 34 via the combining section 84 and generates a clock frequency f s which is supplied to the A / D converter 12. In response to this, the A / D converter samples the information read from the recording medium so that approximately N samples per bit to be detected are generated. As the linear velocity of the record carrier changes, i.e., increases or decreases, the frequency of the generated servo pulses increases or decreases. As a result, the clock frequency f s increases or decreases. However, if the recording medium speed increases (decreases), the information signal is read at an increased (decreased) speed, and this information signal is sampled using the increased (decreased) clock frequency f s , so that eventually, Approximately N samples per bit are generated by the A / D converter 12, regardless of the record carrier speed.
    Thus, the control loop consisting of components 48, 60, 34 constitutes an approximate control loop such that at the output of the A / D converter 12, an approximately constant number N of samples per bit to be detected are output. In this case, N may be selected as 3 as an example.
    The equalizer 16 also receives a clock frequency f s . FIG. 6 shows an example of an embodiment of the equalizer 16, FIG. 7 shows the magnitude characteristic M 1 as a function of the frequency of the information signal read out from the recording medium at the specified speed v 1 , FIG. 8. Denotes the frequency characteristic of the equalizer 16 at the specific record carrier speed v 1 described by the curve H 1 . This magnitude characteristic M 1 has a specific magnitude M 1 (f b ) at the bit frequency f b .
    The delay element denoted by T inside the equalizer shown in FIG. 6 is controlled by the clock frequency f s and realizes a delay T equal to 1 / f s . Due to this delay, the equalizer 16 of FIG. 4 implements the frequency characteristic H 1 shown in FIG. 8.
    In the case of changing the recording medium speed such as reducing the speed by 2 times, the magnitude characteristic of the signal read out from the recording medium is reduced by 2 times, and thus changes to the characteristic M 2 shown in FIG. The magnitude M 2 (f b ') at the new bit frequency f b ' is equal to M 1 (f b ). Due to the control loop consisting of the components 48, 60 and 34 described above, the clock frequency f s changes (decreases) with the same ratio of two. Accordingly, in the sense that the delay of the equalizer is increased by the same double, the delay of the equalizer shown in FIG. 6 changes. Therefore, this characteristic H 2 is reduced by the same amount as the magnitude characteristic M 2 of the information signal read out from the recording medium.
    Thus, the operation of the equalizer 16 equally equalizes the signal read out from the recording medium by the equalizer 16 under the control of the clock frequency f s generated by the oscillator 34, regardless of the recording medium speed. Let's do it.
    The conversion section 82 generates at its output a control signal given to the oscillator 74 via the synthesis section 76 to position the oscillation section 74 at the frequency f s / N.
    At this time, it should be noted that the PLL 30 controls the frequency of the oscillator 74 toward f b . However, the PLL 30 has a small acquisition range, for example, 10% smaller or larger than f b , see FIG. 9. Line 90 and the signal, via the synthesis unit 76 uses the applied control signal to the VCO (74), VCO (74 ) is a line in the vicinity of f b as shown by 92 quick change shown in Figure 9 do. In the absence of fine control, using the control signal cs3 described later, the VCO 74 maintains the frequency value f b ", for example, the disturbance caused by the change of the speed of the recording medium is shown in FIG. As indicated by, the PLL 30 is released from the locked state because it is out of frequency from the capture range of the loop 30.
    However, the above-mentioned phase comparator 70 and the loop filter 72, a control signal cs3 from the required bit frequency f b and generates a control signal corresponding to a measure of the deviation of the frequency of the VCO (74). Note that the required bit frequency f b is not a constant frequency value and changes as the recording medium speed changes.
    The control signal cs3 is given to the second input of the signal synthesizing unit 84. Such a control signal cs3 controls the frequency of the VCO 74 toward the bit frequency f b required as the fine control signal. This is shown as line 94 in FIG. 9. For example, the disturbance caused by the change in velocity of the cross media causes a change in the frequency of the VCO 74. However, this change is kept within the capture range of the loop 30 as indicated by curve 94 shown in FIG. 9, so that the PLL 30 remains locked.
    4 shows a buffer memory 100 that may be connected to the output terminal 28 of the apparatus shown in FIG. 3. Such a buffer memory 100 performs a function as a FIFO memory. A sequence consisting of a plurality of bits detected by the bit detector 24 can be stored in a buffer memory having a specific frequency f in equal to the frequency f b generated by the oscillator 74.
    The detected plurality of bits can be retrieved from the buffer memory 100 using the read clock frequency f out . This frequency f out can be less than or greater than f in . In the former case, the buffer memory 100 is gradually filled with information, causing an overflow. In the latter case, the buffer is gradually emptied until there are no more bits to output at the required rate of f out . To overcome these problems, the buffer memory 100 has an output 102, at which the signal indicating the degree of charge of the buffer memory 100 can be used. This signal is converted into a control signal in the converter 104 and output to the motor controller 106. The motor control unit 106 outputs the drive signal 46 to the motor 48.
    When f out is greater than f in , the degree of charge decreases. As a result, a control signal is generated so that the feed speed of the recording medium 4 increases. If f out is less than f in , the degree of filling increases. As a result, a control signal is generated so that the feed speed of the recording medium 4 decreases. Fine control through components 70, 72, 82 and 34, as well as approximate control loops through components 60, 82 and 34, automatically adjusts itself to varying feed rates of the recording medium, as described above. Transform.
    FIG. 5 shows another embodiment of the A / D converter 12 shown in FIG. 1, 2, or 3. The A / D converter shown in FIG. 5 includes an A / D converter 110 that receives a sampling frequency generated by the oscillator 112 via a clock input 114. The sampling frequency generated by this oscillator 112 may be higher than f s . The sample generated by the converter 110 is sent to the down sampler, which downsamples the signal given to its input 118 in response to the first control signal cs1 applied to the control signal input 120. At its output 14, there is an information signal sampled at the frequency f s .
    At this time, the down sampler 116 may not only down sample an array of a plurality of samples applied to its input 118, but also interpolate if necessary to obtain its output signal. have.
    Although the present invention has been described with reference to preferred embodiments of the invention, it is obvious that these embodiments are not given examples to limit the invention. Accordingly, various modifications may be made to those skilled in the art without departing from the scope of the present invention as set forth in the claims. For example, the control signal cs2 may be derived from a plurality of sync patterns recorded on the recording medium. Moreover, in another embodiment, the third control signal cs3 may be generated in a manner different from that described above, ie from the output 102 of the buffer memory 100. In such an embodiment, f out is derived, for example, from component 82 and has the same value as f s / N, see FIG. 3. At this time, since the control signal present in the output 102 of the buffer memory 100 is a measured value of the integral of f b -f s / N, it becomes a measured value of the integral of the control signal cs3. Furthermore, the recording medium may be a longitudinal recording medium having a magnetic, magneto-optical or optical form, a rectangular card form or a disc-shaped recording medium.
    Moreover, the present invention encompasses all novel features or combinations of these features.
    Related literature
    (D1) USP 5,569,912 (PHN 14.875)
    权利要求:
    Claims (12)
    [1" claim-type="Currently amended] Reproduces from the recording medium information containing a sequence consisting of a plurality of bits represented by a plurality of marks in a track on the recording medium 4,
    Reading means (6, 8) having a read head (6) for reading a plurality of marks from the track and generating a read signal from said track,
    A / D conversion means 12, 34 for A / D converting the read signal using a specific clock frequency f s in response to the first control signal cs1,
    -Bit detection means (130; 24) having an input connected to the A / D conversion means and configured to retrieve a sequence consisting of a plurality of bits from a signal given to its input using a specific bit frequency f b and the specific Means for deriving a bit frequency (130; 30),
    Output means (101; 28) for supplying a sequence consisting of a plurality of bits,
    -A reproducing apparatus having derivation means for deriving said first control signal,
    The derivation means outputs a first control signal depending on the second control signal (132; 134) and means for deriving a second control signal (cs2) representing the relative speed of the read head relative to the plurality of marks from the read signal; And a reproducing means (84).
    [2" claim-type="Currently amended] The method of claim 1,
    The derivation means further comprises means (130; 70, 72) for deriving a third control signal (cs3) having a relationship with the bit frequency, and the means (84) for outputting the first control signal comprises a second control signal. And outputting the first control signal in dependence on the third control signal.
    [3" claim-type="Currently amended] The method according to claim 1 or 2,
    The plurality of marks reproduce information from a recording medium including a plurality of marks having different lengths, and the derivation means 132 relies on the average length of the signal portion inside the read signal corresponding to the plurality of marks. And a control device (cs2).
    [4" claim-type="Currently amended] The method according to claim 1, 2 or 3,
    A plurality of marks reproduce information from a recording medium comprising a plurality of servo marks indicating the position of the read head relative to the recording medium or track, wherein the derivation means 134 is provided within a read signal corresponding to the plurality of servo marks. And reproducing a second control signal (cs2) depending on the signal portion.
    [5" claim-type="Currently amended] The method of claim 4, wherein
    The plurality of servo marks comprise a plurality of track changes or headers or prepits or fine clock marks at a predetermined distance between the plurality of marks, wherein the derivation means comprises a signal portion within a read signal corresponding to the distance. And derive a second control signal (cs2) in dependence upon.
    [6" claim-type="Currently amended] The method of claim 5,
    And a means for calculating a predetermined distance depending on an indicator of a radial position of the read head, such as a track number, for reproducing information from a disc-shaped recording medium.
    [7" claim-type="Currently amended] The method according to any one of claims 1, 2, 3, 4, 5 or 6,
    Information is reproduced from a disc-shaped recording medium, the derivation means comprising means 50 for deriving a fourth control signal cs4 based on the rotational speed of the disc and the radial position of the read head, and 4 The control signal is a measured value of the nominal relative speed of the read head with respect to the recording medium at the rotational speed and the radial position, and means for outputting the first control signal 84 depends on the fourth control signal. It is configured to output a control signal, or any read signal may not be used from the read head or may be dependent on the conditions of the device, such as the time period when the read head moves radially across the track to access different parts of the track. And a fourth control signal instead of the second control signal.
    [8" claim-type="Currently amended] The method according to any of the preceding claims,
    And the apparatus further comprises voltage controlled oscillation means (34) for generating the specific clock frequency in response to the first control signal (cs1).
    [9" claim-type="Currently amended] The method according to any one of claims 1 to 8,
    And the A / D converting means further comprises down sampler means (116) for generating a plurality of sample values at the specific clock frequency in response to the first control signal (cs1).
    [10" claim-type="Currently amended] The method according to any one of claims 1 to 9,
    And a digital equalizer filter means (16) is provided to perform an equalization process on the digitalized read signal using the specific clock frequency to obtain an equalized information signal.
    [11" claim-type="Currently amended] The method according to any one of claims 1 to 10,
    And the derivation means is configured such that a specific clock frequency and a bit frequency return a constant ratio N with respect to each other and generate a first control signal, where N is a positive constant.
    [12" claim-type="Currently amended] The method of claim 11,
    The derivation means generates a specific clock frequency f s such that N samples per bit are output by the A / D conversion means 12, regardless of the relative speed of the at least one read head relative to the track. The fine control signal cs3 to correct the deviation of the specific clock frequency expressed in the number of samples per bit from the value of the N samples per bit and the value of N samples per bit. And a fine control signal generating means (30, 70, 72) for deriving.
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    US20040172148A1|2004-09-02|Signal processing apparatus and signal processing method
    KR20020089786A|2002-11-30|Optical recording medium on which multi-modulated header signals are recorded, method and apparatus for recording the header signals, method and apparatus for reproducing the header signals
    同族专利:
    公开号 | 公开日
    WO1999056283A2|1999-11-04|
    JP2002506557A|2002-02-26|
    TW463154B|2001-11-11|
    EP0992037A2|2000-04-12|
    WO1999056283A3|2000-01-20|
    CN1266529A|2000-09-13|
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    1998-04-28|Priority to EP98201370
    1998-04-28|Priority to EP98201370.8
    1999-04-20|Application filed by 요트.게.아. 롤페즈, 코닌클리케 필립스 일렉트로닉스 엔.브이.
    2001-02-26|Publication of KR20010014250A
    优先权:
    申请号 | 申请日 | 专利标题
    EP98201370|1998-04-28|
    EP98201370.8|1998-04-28|
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