WO2003098798A1 - Circuit de limitation de la vitesse de balayage et disque optique - Google Patents
Circuit de limitation de la vitesse de balayage et disque optique Download PDFInfo
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- WO2003098798A1 WO2003098798A1 PCT/JP2003/006145 JP0306145W WO03098798A1 WO 2003098798 A1 WO2003098798 A1 WO 2003098798A1 JP 0306145 W JP0306145 W JP 0306145W WO 03098798 A1 WO03098798 A1 WO 03098798A1
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- signal
- slew rate
- optical disk
- variable
- disk device
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Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/095—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for discs, e.g. for compensation of eccentricity or wobble
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/20—Signal processing not specific to the method of recording or reproducing; Circuits therefor for correction of skew for multitrack recording
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/005—Reproducing
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
- G11B7/005—Reproducing
- G11B7/0053—Reproducing non-user data, e.g. wobbled address, prepits, BCA
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
- H03G11/00—Limiting amplitude; Limiting rate of change of amplitude ; Clipping in general
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2407—Tracks or pits; Shape, structure or physical properties thereof
- G11B7/24073—Tracks
- G11B7/24082—Meandering
Definitions
- the present invention limits the slew rate of an abnormal component when the input signal includes an abnormal component having a large slew rate whose level changes rapidly, and the output signal includes the abnormal component. It relates to a slew rate limiting circuit that removes as much as possible, and also relates to an optical disk device that records and reproduces data such as documents, images, music, etc. on an optical disk, and in particular, an optical signal recorded on a recordable / reproducible optical disk. TECHNICAL FIELD The present invention relates to an optical disk device suitable for reproducing data and detecting an LPP (land pre-pit) signal. Background art
- FIG. Figure 8 shows part of the disk surface of DVD-R / RW.
- This optical disk (hereinafter also referred to as DVD-R / RW) 10 has grooves (groups) 12 for recording information.
- groups 12 for recording information.
- 1 2 Force Spiral, meandering at a specific amplitude and a specific period (pulling). It is formed. This is called a pebble.
- the reflected light when the meandering group 12 is irradiated with the laser spot 13 is detected by a push-pull method by a photodetector divided into right and left (not shown). Thereby, a light amount difference is detected.
- This detected signal is called a wobble signal.
- a reference clock signal for writing can be generated from the wobble signal.
- LPP land pre-pit
- the CD-R / RW wobble signal is a continuous signal whose frequency at 1x speed is 22.05 KHz ⁇ 1 KHz.
- address information called ATIP (Absolute Time In Pregroove) is superimposed on a wobble signal by FM modulation, and the frequency band has a width.
- the DVD-RZRW10 wobble signal has a single frequency of 140.65 KHz (at 1x speed), no address information is superimposed, and the LPP signal obtained from the LPP 18 Is used as address information
- the land on one side where the LPP 18 is formed is discontinuous. Therefore, when passing through the discontinuous portion, the amount of light entering the left and right photodetectors changes sharply, and as a result of the push-pull, the pulse-like signal is superimposed on the cobble signal as an LPP signal.
- the portion of the LPP 18 connected to the outer circumference of the group 12 (hereinafter referred to as the LPP outer circumference connection portion) 18a is accurately overlapped with the maximum amplitude position of the pebble of the group 12. It occurs at a maximum of 3 wobbles in a row.
- the portion 18b connected to the inner circumference of the group 12 in the LPP 18 (hereinafter referred to as the LPP inner circumference connection portion) 18b is not necessarily arranged at the maximum amplitude position of the pebble, but is arranged at the valley of the pebble. Or be placed on the way.
- the LPP inner circumference connection portion 18b may also occur continuously for a maximum of 3 wobbles.
- address information is recorded on the DVD-R / RW 10 as a combination of LPP signals by the LPP outer peripheral connection portion 18a for three cycles.
- FIG. 10 shows a configuration of a wobble signal and LPP signal reproduction circuit in a conventional optical disk device.
- the poble signal and LPP signal reproducing circuit may be abbreviated as a reproducing circuit.
- This regeneration circuit 20 is composed of an AGC (Auto Gain Controller) 31, 32, which is connected to a four-divided sensor 21, OP amplifiers 23, 24, and HPFs (High Pass Filters) 26, 27, 28, 29 on the input and output sides. , A variable gain differential amplifier 34 with a variable frequency LPF, an over-level limiter 36, a BPF 38, a level hold section 40, a D AC (Digital Analog Converter) 42, an adder 44, It has an AGC 49 with HPFs 46 and 47 connected to the input and output sides, and binarized comparators 51 and 52.
- AGC Automatic Gain Controller
- the quadrant sensor 21 When the laser spot 13 is irradiated on the optical disk 10 as shown in FIG. 8, this reflected light is applied to the four-divided sensor 21 divided into four as shown by A, B, C and D in FIG. To form a spot image.
- the quadrant sensor 21 first generates an A + D signal and a B + C signal, which are obtained by adding the picked up A, B, C, and D signals in the circumferential direction, in order to reproduce the wobbled signal and the LPP signal.
- a + D signal is a signal on the left side (AD side) in the traveling direction of the group 12 indicated by the arrow Y1 on the drawing
- the B + C signal is a signal on the right side (BC side).
- the A + D signal and the B + C signal are input to HPFs 26 and 27, where DC offset components are removed, and then input to AGCs 31 and 32.
- the amplitudes of both the A + D signal and the B + C signal are aligned to remove the RF component and the common mode noise component.
- the A + D signal and the B + C signal having the constant amplitude are input to the differential amplifier 34 via the HPFs 28 and 29.
- the differential amplifier 34 the difference between the A + D signal and the B + C signal is obtained, and the difference is processed by the set gain and frequency variable LPF to obtain a difference signal DIF ⁇ . Processing takes the difference between A + D and B + C signals As a result, the pit data 14 is canceled out and lost, and the gain of the double signal and the LPP signal included in each of the A + D signal and the B + C signal is emphasized.
- the LPF signal component of the difference signal D FOF output from the differential amplifier 34 is removed by the over-level / limiter 36, leaving only the negative signal component.
- the sample signal 37 is output to the level hold unit 40 and the HPF 46 via the BPF 38. Then, the DC offset component and noise are removed from the HP F 46 through the circuits of the AGC 49 and the HP F 47, and the amplitude is made constant. As a result, the sample signal 54 is reproduced.
- the wobble signal 54 is input to the binarization comparator 51, and is binarized by comparison with the slice level V1 to become the binarization sample signal 56.
- the limit value SLL of the over-level limiter 36 is generated as follows. That is, the peak and bottom of the output level of the BPF 38 are held by the level hold unit 40 (peak hold and bottom hold). A predetermined DC offset voltage output from the DAC 42 is added to each of the hold values by the adder 44 to generate a limit value SLL.
- This limit value SLL is also used as the slice level V 2 of the binarization comparator 52. That is, the slice level V2 is a peak hold value or a potom hold value to which the offset voltage is added.
- the peak hold value and the bottom hold value are assumed to be offset voltages added to these values.
- the slice level V2 is compared with the difference signal DIFO in the binarization comparator 52, so that the binarized LPP signal 58 is reproduced.
- whether the slice level V2 input to the binarization comparator 52 is set to the peak hold value or the bottom hold value depends on the polarity of the LPP component included in the difference signal DIFO. For example, as shown in FIG. 11 (a), the LPP signals P1 and P2 from the LPP outer peripheral connection portion 18a appear in an upward pulse shape, so the peak hold value PL is used. If the polarity is reversed by the pickup, LPP signal P3 and P4 by LPP inner connection 1'8b The bottom hold value BL is used.
- the pulse-like LPPP signals PI and P2 superimposed on the difference signal DIFO are removed by the peak hold value PL. Further, the pulse-like LPP signals P3 and P4 superimposed on the difference signal DIF # are removed by the bottom hold value BL. As a result of this processing, the pebble signal 37 shown in FIG. 11B is output from the over-level limiter.
- the difference signal DIFO is compared with the peak hold value PL, and the peak hold value PL force and the protruding LPP signal P l, P 2 is detected, and becomes a binarized LPP signal 58.
- this type of conventional optical disk device include those described in, for example, JP-A-7-296395 and JP-A-2002-216363.
- the conventional optical disk device has the following problems. If the LPP inner connection 18b of the optical disk 10 is located near the center of the amplitude of the cobbles, as shown in Fig. 11 (a), the LPP inner connection 18b near the center is The LPP signals P3 and P4 protrude from the vicinity of the amplitude center C1 of the difference signal DIFO. Even if these LPP signals P 3 and P 4 are removed by the bottom hold value B L, as shown by P 3 a and P 4 a in FIG. ? signal? 3, The component of P4 cannot be obtained.
- the time A jitter occurs in which the signal fluctuates along the axis. That is, the jitter performance is degraded.
- the optimum slice level V2 for removing the LPP signal of the LPP outer peripheral connection portion 18a from the difference signal DIFO changes due to the fluctuation of the amplitude of the wobble signal, for example, the peak shown in FIG.
- the slice level V2 changes due to the hold value PL, as shown by the reference symbol P1a
- the remaining P1 component of the LPP signal remains.
- Such a residual component P 1a of the LPP signal is generated, and the variation of the residual component also leads to deterioration of the jitter performance.
- the remaining component of the LPP signal P 1 a is also a factor that changes the amplitude of the cobbled signal after the BPF 38.
- the peak hold value PL (slice level V 2) is added to the pebble signal component as shown in Fig. 11 (a) due to the fluctuation of the noise pebble signal component. If the protruding pulse component P5 exists, an erroneous detection of detecting the pulse P5 as the LPP signal 58a occurs, as shown in FIG. 11C.
- each of the A, B, C, and D signals has an RF signal due to the difference in the reflectance between the mark portion 12a and the unmark portion 12b, which is the pit data 14 shown in FIG. If a component is included, the amplitude of the sample signal and the LPP signal changes depending on the noise due to the RF component and the presence or absence of a mark, and an optimum limit value SLL cannot be obtained. Therefore, the slice level V2 also changes.
- the present invention has been made in view of such a problem, and has been made in consideration of the above-described problems. Accordingly, the present invention provides a single rate limiting circuit and an optical disk that can appropriately reproduce a wobble signal and an LPP signal without increasing the circuit scale. It is intended to provide a device. Disclosure of the invention
- a slew rate limiting circuit includes a MOS transistor having a gate to which an input signal is input, and a first current source connected in series with the MOS transistor on a source side of the MOS transistor.
- a second current source connected in series with the MOS transistor on the drain side of the MOS transistor; and a capacitor connected between the source of the MOS transistor and a reference potential. It is characterized by.
- the MOS transistor when the input voltage level sharply increases, that is, when the input voltage increases (or decreases) at a slew rate higher than usual, the MOS transistor is turned on and the output voltage (reference potential) is increased. Increase (or decrease) at a slew rate determined by the difference between the second current source and the first current source and the capacitance value of the capacitor. This slew rate is such that the output voltage increases (or decreases) per unit time. Therefore, even if the input voltage level increases (or decreases) rapidly, the output voltage increases (or decreases) rapidly. ) The level will be suppressed. In other words, the sharp increase (or decrease) level of the input voltage can be eliminated.
- the first current source and the second current source according to claim 1 are any one of the first current source and the second current source. It is characterized in that one or both consist of a variable current source.
- the slew rate limiting circuit according to claim 3 of the present invention is characterized in that, in claim 1, the capacitor has a variable capacitance value.
- the optical disc device is further characterized in that an information recording track spirally formed from the inner circumference to the outer circumference of the disk in a meandering manner at a predetermined period is connected to the track between the tracks.
- an optical disc device that reproduces, from an optical disc having an inter-track portion for reproducing address information formed as described above, a pop signal as meandering information of the track and an address signal by the inter-track portion, By taking the difference between a split optical sensor that detects two signals by scanning a track with light and the two detection signals detected by the split optical sensor, the wobble signal and the address are obtained.
- a differential amplifier that generates a difference signal including a signal, and a slew rate that limits a signal that changes more steeply than the above-mentioned wobble signal. Further comprising a slew rate limiter that processes the serial differential signal Features.
- An optical disc device according to claim 5 according to the present invention, according to claim 4, further comprising: a bandpass filter to which an output signal of the slew rate limiter is input and a pass frequency band is variable. It is characterized by the following.
- the optical disc device according to claim 6 according to the present invention is characterized in that in claim 5, the pass band of the band-pass filter is variably set according to the rotation speed of the optical disc. I do.
- the noise component and the wobble signal / address signal after detection by the split type optical sensor differ depending on the rotation speed of the optical disk, but the pass band of the band-pass filter is variably set according to the rotation speed. By doing so, it is possible to remove the noise component remaining in the sampled signal output from the slew rate limiter and pass only the sampled signal optimally.
- the optical disc device according to claim 7 of the present invention is the optical disc device according to claim 4, wherein a voltage is generated, and a variable voltage generating means having a variable value of the voltage; and an output signal of the slew rate limiter. And a comparator that reproduces the address signal by comparing the output signal of the adder with a slice signal using the output signal of the adder as a slice level.
- the slice level output from the adder has a waveform synchronized with the same shape as the pebble signal extracted from the difference signal. It can be arranged so as to substantially match the waveform of the included double signal. By comparing such a slice level with the difference signal, an address signal protruding in a pulse form from the pebble signal is properly detected and reproduced. be able to.
- An optical disc device is the optical disc device according to claim 4, wherein the slew rate in the slew rate limiter is increased or decreased as the rotation speed of the optical disc increases. It is characterized by being set.
- the slew rate limiter can properly output the pebble signal. Can be.
- the optical disc device according to claim 9 according to the present invention, wherein the gain of the differential amplifier is variable, and the double signal / address signal included in the difference signal is variable.
- the gain is variably set according to the amplitude of the signal.
- the amplitude of the above-mentioned wobble signal / address signal depending on the disc type can be changed to match the value of the slew rate limiter.
- the optical disk device according to claim 10 of the present invention is the optical disk device according to claim 4, wherein the gain of the differential amplifier is variable and is set according to the number of rotations of the optical disk. It is characterized by the following.
- An optical disc device further comprises an information recording track spirally meandering from the inner circumference to the outer circumference of the disk at a predetermined period, and a track between the tracks.
- an optical disc apparatus for reproducing, from an optical disc having connected and formed inter-track sections for reproducing address information, a pop signal as meandering information of the tracks and an address signal by the inter-track sections, By dividing the difference between the split-type optical sensor that detects two signals by scanning the track with light and the two-system detection signals detected by the split-type optical sensor, the wobble signal and the address signal are obtained.
- Generate differential signal including differential An amplifier, a MOS transistor whose gate receives the difference signal, a first current source connected in series with the MOS transistor on the source side of the MOS transistor, and a MOS transistor connected on the drain side of the MOS transistor on the drain side.
- a second current source connected in series with the transistor, a slew rate limiting circuit having a capacitor connected between the source terminal and the output terminal of the MOS transistor, and processing the difference signal. It is characterized by the following.
- the optical disk device according to claim 12 of the present invention is the optical disk device according to claim 11, wherein the first current source and the second current source of the slew rate limiting circuit are It is characterized in that one or both of them comprise a variable current source.
- the slew rate can be set arbitrarily, a signal that changes more steeply than a pebble signal included in the difference signal can be appropriately removed by the slew rate limiting circuit.
- the optical disk device according to claim 13 of the present invention the optical disk device according to claim 11, wherein the capacitor of the slew rate limiting circuit has a variable capacitance value.
- the slew rate can be set arbitrarily, a signal that changes more steeply than a pebble signal included in the difference signal can be appropriately removed by the slew rate limiting circuit.
- the optical disc device according to claim 14 of the present invention is the optical disc device according to claim 11, wherein an output signal from an output terminal of the slew rate limiting circuit is input, and a pass frequency band is variable.
- a bandpass filter is provided. This makes it possible to reproduce the wobble signal more appropriately by setting the pass frequency band of the band-pass filter to a band that allows only the wobble signal to pass.
- the pass band of the band-pass filter is variably set according to the number of rotations of the optical disk. It is characterized by.
- the noise component and the wobble signal / address signal after detection by the split-type optical sensor differ depending on the rotation speed of the optical disc, but the pass band of the band-pass filter is variable according to the rotation speed.
- An optical disc device is the optical disc device according to claim 11, wherein a voltage is generated, and a variable voltage generating means having a variable value of the voltage; An adder for adding the voltage to the output signal, and a comparator for reproducing the address signal by comparing the output signal of the adder as a slice level with the difference signal. .
- the slice level output from the adder has a waveform that is substantially the same in shape and synchronized with the pebble signal extracted from the difference signal. It can be arranged so as to substantially match the waveform of the included pebble signal. By comparing such a slice level with the difference signal, it is possible to properly detect and reproduce an address signal protruding in a pulse form from the sample signal.
- the optical disk device according to claim 17 of the present invention is the optical disk device according to claim 11, wherein the slew rate in the slew rate limiting circuit is set to a larger value as the rotation speed of the optical disk increases. It is characterized by being performed.
- the slew-rate limiting circuit can appropriately output the wobble signal. be able to.
- the optical disk device according to claim 18 according to the present invention, wherein the gain of the differential amplifier is variable, and the coupon signal Z included in the difference signal is variable.
- the gain is variably set according to the amplitude of the address signal. It is specified that it is specified.
- the amplitude of the above-mentioned wobble signal address signal depending on the disc type can be changed to match the value of the slew rate limiting circuit.
- the optical disc device according to claim 19 of the present invention is the optical disc device according to claim 11, wherein a gain of the differential amplifier is variable and is set according to a rotation speed of the optical disc. It is characterized by the following.
- the bandwidth of the sampled signal / address signal detected by the split type optical sensor differs depending on the rotation speed of the optical disk, but the gain value of the differential amplifier / the slew rate limiting circuit depends on the rotation speed.
- FIG. 1 is a block diagram showing a configuration of a sample signal and L / L signal reproduction circuit of an optical disc device according to an embodiment of the present invention.
- FIG. 2 is a diagram showing a no-bore signal and each signal in an L-level signal reproducing circuit of the optical disk device.
- FIG. 3 is a diagram showing a first configuration example of a slew limiter in a wobble signal and L / L signal reproduction circuit of the optical disc device.
- FIG. 4 is a waveform diagram of an input voltage and an output voltage in the slew rate limiter of the first configuration example.
- FIG. 5 is a diagram showing a second example of the configuration of the slew rate limiter in the wobble signal and LP signal recovery circuit of the optical disk device.
- FIG. 1 is a block diagram showing a configuration of a sample signal and L / L signal reproduction circuit of an optical disc device according to an embodiment of the present invention.
- FIG. 2 is a diagram showing a no-bore signal and
- FIG. 6 is a waveform chart when the effect of the present embodiment is verified.
- FIG. 7 is an enlarged view of a predetermined section shown in FIG.
- FIG. 8 is a diagram showing a configuration of an optical disk.
- FIG. 9 is an enlarged view of the group, land and LPP on the optical disc.
- FIG. 10 is a block diagram showing a configuration of a wobble signal and LPP signal reproduction circuit of a conventional optical disk device.
- FIG. 11 is a diagram showing a cobble signal of the conventional optical disk device and each signal in the LPP signal reproducing circuit.
- the characteristic configuration of the wobbled signal and LPP signal reproducing circuit 60 of the present embodiment shown in FIG. 1 is that a slew rate limiter (slew rate limiting circuit) is used instead of the over-level limiter 36 of the reproducing circuit 20 shown in FIG. The point is that 1 is used. Also, remove the level horn resistor section 40 shown in FIG. 10, connect the signal output terminal of the slew rate limiter 61 and the adder 44 as shown in FIG. 1, and further connect the output side of the slew rate limiter 61. The point is that a variable frequency band type is used as the BPF 38a to be connected.
- a slew rate limiter slew rate limiting circuit
- the reproducing circuit 60 of the present embodiment includes the four-divided sensor 21, the OP amplifiers 23, 24, and the AGCs 31, 3 connected to the HPFs 26, 27, 28, 29 on the input / output side 2, a variable gain differential amplifier 34 with a variable frequency LPF, a slew rate limiter 61, a BPF 38a, a DAC 42, an adder 44, and HPFs 46 and 47 on the input and output sides. It is configured to include the connected AGC 49 and the binarized comparators 51 and 52.
- the slew rate limiter 61 can change the slew rate (change rate of rise / fall of output signal) according to the rotation speed of the DVD-R / RW10.
- the slew rate is limited so that the low-pass signal is not passed through the difference signal DIFO output from the differential signal DIFO. This restriction is made to increase the slew rate as the rotation speed increases.
- the slew rate can be specified in 125 mV increments, for example, from 125 to 2000 mV / ⁇ s in order to change according to the rotation speed.
- the components of the cobbled signal 63 shown in FIG. 2 (b) do not pass through the LPP signals P1 to P4 included in the difference signal DI FO shown in FIG. 2 (a). It is possible to output through only. Further, in the slew rate processing, the whisker-like amplitude component superimposed on the ripple component of the difference signal DIF # shown in FIG. 2 (a) is also removed as shown in FIG. 2 (b).
- the amplitude component is the amplitude that changes sharply depending on the noise due to the RF component and the presence or absence of the mark as described in the conventional example. However, as described above, when the slew rate is limited, the amplitude that changes sharply The components cannot pass through and will be removed.
- FIG. 1 An example of a circuit configuration of such a slew rate limiter 61 is shown in FIG.
- a MOS transistor Q 1 a current source 1 for flowing a constant current I 1
- a current source for flowing a constant current I 2, 2 a capacitor C 1 serving as a load of the MOS transistor Q 1.
- the MOS transistor Q1 When the level of the input voltage Vin increases sharply as indicated by reference signs a1 and a2 in FIG. 4, the MOS transistor Q1 is turned on, and the output voltage Vout becomes constant current I2 and constant current I2. It increases at the slew rate determined by the difference between I1 (I2-I1) and the capacitance value C1 of the capacitor C1. On the other hand, when the level of the input voltage Vin decreases sharply as shown by reference signs b1 and b2, the MOS transistor Q1 turns off, and the output voltage Vout force constant current I1 and the capacitance value C1 It decreases at the slew rate determined by.
- the pulse-like noise components a1, b1 and b2, a2 generated in the input voltage V in are substantially removed, and only the substantially input voltage V in can be output as the output voltage V out.
- the slew rate limiter 61 uses the L? Signal shown in Figure 2 (a)? 1 ⁇ ? 4 is removed, and only the approximate signal 63 shown in FIG. 2 (b) is output.
- the output / level correction circuit 5 includes an operational amplifier OP 1, an N-type MOS transistor Q 2, and a current source 6. Also, the operational amplifier OP 1 forms a voltage follower with the MOS transistor Q 2.
- the differential amplifier 34 connected in front of such a slew rate limiter 61 converts the A + D and B + C signals input from the HPFs 28 and 29 into constant amplitude RF components due to the recorded pits. After performing AGC (auto gain control), take the difference and generate a wobbled / LPP component. Since this output differs depending on the disc type, a gain value of, for example, 0.66 / 1.33 / 2.66 is set so that the optimal gain can be selected.
- the slew rate The range of change of the value of the limiter 61 is reduced, so that the wobble / LPP component can be optimally detected.
- the frequency band of the BPF 38a connected downstream of the slew rate limiter 61 can be changed according to the rotation speed by switching the frequency using an input clock or a register. By selecting this frequency band, a wobble component can be optimally detected from the wobble signal 63.
- the adder 44 adds the DC offset voltage V3 from the DAC 42 to the cobble signal 63 output from the slew rate limiter 61 to generate the slice level V2a of the binary comparator 52.
- the slice level V 2 a can be varied from 0 to 375 mV in steps of 25 mV, for example, by the offset voltage V 3. Since the slice level V2a is generated based on the pebble signal 63 obtained by extracting the pebble component from the difference signal DIFO, the sine wave V2a is included in the difference signal DIFO as shown in FIG. 2 (c). It has a waveform synchronized with the same shape of the wobble component. Therefore, by raising or lowering the slice level V 2 a by the offset voltage V 3, it is possible to arrange the slice level V 2 a substantially in accordance with the waveform of the single component.
- a + D and B + C signals are generated by adding the A, B, C, and D signals picked up by the four-divided sensor 21 in the circumferential direction.
- the A + D and B + C signals are input to HPFs 26 and 27, where the DC offset component After removal of, both amplitudes are aligned at AGC 31 and 32.
- the A + D signal and the B + C signal having the constant amplitude are input to the differential amplifier 34 via the HPFs 28 and 29.
- the differential amplifier 34 a difference between the A + D signal and the B + C signal is obtained, and the difference signal DI FO is obtained by processing with a set gain and a variable frequency LPF.
- the LPP components P 1 to P 4 shown in FIG. 2A are removed by the slew rate limiter 61.
- the remaining cobbled signal 63 shown in FIG. 2 (b) is output to the power adder 44 and the BPF 38a.
- the offset voltage V3 is added to the sample signal 63, and a slice level V2a shown in FIG. 2C is obtained. This slice level V2a force binary dani conno ,.
- the comparator 52 reproduces a binarized LPP signal 58b by comparing the difference signal D FO with the difference signal D INFO.
- the BPF 38a after removing unnecessary components such as noise remaining in the cobbled signal 63, the DC offset component and noise are removed by the circuits of the HP F 46 to the AGC 49 and the HP F 46. The amplitude is constant. As a result, the soft signal 54b is reproduced.
- the opponent signal 54b is input to the binary comparator 51, and is binarized by comparison with the slice level VI, thereby reproducing the binarized signal 56b.
- the slew rate limiter 61 steers more steeply than the sample signal included in the difference signal DI FO generated by the differential amplifier 34.
- the slew rate was limited so as not to pass the changing signal, and the difference signal DIFO was processed and output with this slew rate.
- the output signal of the slew rate limiter 61 is input and the BPF 38a is provided with a variable pass band for restricting and passing the frequency band, the pass frequency band of the BPF 38 By making the band pass through, it is possible to more appropriately reproduce the wobble / playback signal.
- an offset voltage V 3 is generated from the DAC 42, the offset voltage V 3 and the cobble signal 63 from the slew rate limiter 61 are added by the adder 44, and the added signal is slice level V As 2a, an LPP signal 58b is reproduced by comparing the difference signal DIFO in the comparator 52. Since the slice level V 2 a output from the adder 44 has a waveform synchronized with the same shape as the cobble signal extracted from the difference signal DIFO, the entire slice level V 2 a is raised and lowered by a voltage. The difference signal can be arranged so as to substantially match the waveform of the pebble signal included in the DIFO. By comparing such a slice level V2a with the difference signal DIFO, it is possible to properly detect the LPP signal 58b protruding in a pulse form from the pebble signal.
- the slew rate of the slew limiter 61 is set to a larger value as the rotation speed of the optical disc 10 is faster, so that the rotation speed of the optical disc 10 becomes faster, and the split type optical sensor detects the slew rate. Even if the rate of change of the rising edge of the wobble signal becomes large, the slew rate limiter 61 can output the wobble signal properly.
- the amplifier gain is changed in the differential amplifier 34, it is possible to absorb the difference in the difference signal amplitude due to the disk type and to reduce the required slew rate setting value.
- FIG. 7 is an enlarged view of the section 71 shown in FIG. In FIGS. 6 and 7, the waveform shown in (a) is output from the differential amplifier 34. Difference signal DIFO.
- the waveform shown in (b) is a waveform signal obtained by passing the difference signal DIFO from the differential amplifier 34 directly through the BPF 38 without using the over-level limiter 36 in the conventional configuration shown in FIG. ,
- a first conventional op / re signal a post signal obtained from the BPF 38 after passing through the over-level limiter 36 shown in FIG. 10
- a second conventional op signal a post signal obtained from the BPF 38 after passing through the over-level limiter 36 shown in FIG. 10
- three signals, ie, a signal obtained from the BPF 38a after passing through the slew rate limiter 61 hereinafter, referred to as the signal of the present invention). It shows the status.
- the waveform shown in (c) is a waveform 75 of the period difference between the first conventional wobble signal and the ideal wobble signal.
- the waveform shown in (d) is a waveform 77 of the period difference between the second conventional wobble signal and the ideal wobble signal.
- the waveform shown in (e) is a waveform 79 of the difference between the periods of the double signal of the present invention and the ideal double signal.
- (f) is a waveform 755a, 777 that shows the jitter ratio (%) obtained by dividing the standard deviation of the waveforms 75,77,79 of the above difference and dividing by the period of the ideal ⁇ -opnore signal. a, 7 9 a
- the jitter ratio (%) shown in (f) is best when the waveform 79a obtained by the configuration of the present invention close to 1. From this, In the detection of the signal 58b, it is sufficient to optimize the offset amount by the DAC 42 so that the signal 58b can be easily detected, and it is understood that it is not necessary to consider the influence on the pseudo signal.
- the configuration is not increased in size by setting the limit value of the slice level and the limit value of the over-level limiter differently, and the level holding unit 40, which is a conventional component, is not used.
- the circuit scale can be reduced accordingly.
- this slew rate limiting circuit By adopting this slew rate limiting circuit, a diode is not used unlike the conventional circuit, and accordingly, the number of components can be reduced as compared with the conventional circuit. Also, since a diode is not used unlike a conventional circuit, it is suitable to be configured with a CMOS integrated circuit. In addition, this slew rate limiting circuit Since a transistor is used, the input impedance can be extremely high, which eliminates the need to provide a buffer circuit on the input side.
- the slew rate limiter limits the slew rate so as not to pass a signal that changes more steeply than a pebble signal included in the difference signal generated by the differential amplifier. Process and output the signal.
- a signal that changes more steeply than a pebble signal included in the difference signal is removed. That is, since the endless signal and the noise component included in the difference signal together with the poble signal are removed, only the poble signal can be output from the slew rate limiter. Therefore, the wobble signal can be properly reproduced.
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- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Optical Recording Or Reproduction (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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KR1020047013935A KR100716087B1 (ko) | 2002-05-16 | 2003-05-16 | 슬루율 제한 회로 및 광 디스크 장치 |
JP2004506178A JP4425786B2 (ja) | 2002-05-16 | 2003-05-16 | スルーレート制限回路および光ディスク装置 |
US10/513,514 US7203143B2 (en) | 2002-05-16 | 2003-05-16 | Slew rate limiting circuit and optical disc apparatus |
Applications Claiming Priority (4)
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JP2002141733 | 2002-05-16 | ||
JP2002/141733 | 2002-05-16 | ||
JP2003/10018 | 2003-01-17 | ||
JP2003010018 | 2003-01-17 |
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WO2003098798A1 true WO2003098798A1 (fr) | 2003-11-27 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/JP2003/006145 WO2003098798A1 (fr) | 2002-05-16 | 2003-05-16 | Circuit de limitation de la vitesse de balayage et disque optique |
Country Status (5)
Country | Link |
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US (1) | US7203143B2 (ja) |
JP (1) | JP4425786B2 (ja) |
KR (1) | KR100716087B1 (ja) |
CN (1) | CN100533966C (ja) |
WO (1) | WO2003098798A1 (ja) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2009009672A (ja) * | 2007-06-29 | 2009-01-15 | Panasonic Corp | 情報記録装置および情報記録方法 |
Families Citing this family (3)
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CN101005273B (zh) * | 2006-01-20 | 2010-06-23 | 深圳赛意法微电子有限公司 | 具有改善的转换速率的差分放大器 |
US8233229B2 (en) * | 2006-02-16 | 2012-07-31 | Agere Systems Inc. | Systems and methods for reduction of cross coupling in proximate signal lines |
KR20080065100A (ko) * | 2007-01-08 | 2008-07-11 | 주식회사 하이닉스반도체 | 반도체 메모리 소자와 그의 구동 방법 |
Citations (4)
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JPH03160673A (ja) * | 1989-11-17 | 1991-07-10 | Fujitsu Ltd | ディスク装置のサーボ制御回路 |
JPH07162277A (ja) * | 1993-12-10 | 1995-06-23 | Yokogawa Electric Corp | パルス発生装置 |
JP2000182257A (ja) * | 1998-10-09 | 2000-06-30 | Ricoh Co Ltd | 光記録媒体の情報再生方法 |
JP2001312823A (ja) * | 2000-02-21 | 2001-11-09 | Victor Co Of Japan Ltd | プリピット検出装置、プリピット検出方法、位置及び周波数信号の検出回路 |
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DE3572070D1 (en) * | 1984-12-19 | 1989-09-07 | Toshiba Kk | Tracking control system for optical record disc information reproducing apparatus |
JPH0675342B2 (ja) * | 1988-01-21 | 1994-09-21 | 日本電気株式会社 | 情報記録再生装置における位置決め装置 |
JPH07296395A (ja) | 1994-04-27 | 1995-11-10 | Victor Co Of Japan Ltd | 情報再生装置のトラッキング信号検出方法 |
JP3377013B2 (ja) * | 1994-08-18 | 2003-02-17 | 日本電信電話株式会社 | ディスク装置のシーク制御装置及びそれを用いたシーク制御方法 |
JP3367807B2 (ja) * | 1995-10-27 | 2003-01-20 | 株式会社東芝 | 光ディスク再生装置 |
US6487149B1 (en) * | 1998-10-09 | 2002-11-26 | Ricoh Company, Ltd. | Optical recording and reproducing methods for optical disk |
US6552979B1 (en) * | 2000-10-30 | 2003-04-22 | Cirrus Logic, Inc. | Optical servo control circuits and methods using pulse width modulation and offset control for driving an electromechanical motor |
JP2002216363A (ja) | 2000-11-15 | 2002-08-02 | Matsushita Electric Ind Co Ltd | 光ディスク装置および情報読み出し方法 |
-
2003
- 2003-05-16 WO PCT/JP2003/006145 patent/WO2003098798A1/ja active Application Filing
- 2003-05-16 US US10/513,514 patent/US7203143B2/en not_active Expired - Lifetime
- 2003-05-16 JP JP2004506178A patent/JP4425786B2/ja not_active Expired - Fee Related
- 2003-05-16 CN CNB038105373A patent/CN100533966C/zh not_active Expired - Fee Related
- 2003-05-16 KR KR1020047013935A patent/KR100716087B1/ko not_active IP Right Cessation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH03160673A (ja) * | 1989-11-17 | 1991-07-10 | Fujitsu Ltd | ディスク装置のサーボ制御回路 |
JPH07162277A (ja) * | 1993-12-10 | 1995-06-23 | Yokogawa Electric Corp | パルス発生装置 |
JP2000182257A (ja) * | 1998-10-09 | 2000-06-30 | Ricoh Co Ltd | 光記録媒体の情報再生方法 |
JP2001312823A (ja) * | 2000-02-21 | 2001-11-09 | Victor Co Of Japan Ltd | プリピット検出装置、プリピット検出方法、位置及び周波数信号の検出回路 |
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JP2009009672A (ja) * | 2007-06-29 | 2009-01-15 | Panasonic Corp | 情報記録装置および情報記録方法 |
JP4696095B2 (ja) * | 2007-06-29 | 2011-06-08 | パナソニック株式会社 | 情報記録装置および情報記録方法 |
Also Published As
Publication number | Publication date |
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JPWO2003098798A1 (ja) | 2005-09-22 |
KR20040087340A (ko) | 2004-10-13 |
US7203143B2 (en) | 2007-04-10 |
US20050180299A1 (en) | 2005-08-18 |
JP4425786B2 (ja) | 2010-03-03 |
KR100716087B1 (ko) | 2007-05-09 |
CN1653686A (zh) | 2005-08-10 |
CN100533966C (zh) | 2009-08-26 |
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