Source: http://www.google.com/patents/US8089834?ie=ISO-8859-1&dq=7222078
Timestamp: 2014-10-30 13:48:44
Document Index: 49433699

Matched Legal Cases: ['Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60', 'Application No. 60']

Patent US8089834 - Apparatus for controlling servo signal gains of an optical disc drive and ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode,...http://www.google.com/patents/US8089834?utm_source=gb-gplus-sharePatent US8089834 - Apparatus for controlling servo signal gains of an optical disc drive and method of the sameAdvanced Patent SearchPublication numberUS8089834 B2Publication typeGrantApplication numberUS 13/009,668Publication dateJan 3, 2012Filing dateJan 19, 2011Priority dateJun 5, 2006Also published asUS7911891, US20070280066, US20110110205Publication number009668, 13009668, US 8089834 B2, US 8089834B2, US-B2-8089834, US8089834 B2, US8089834B2InventorsChia-Wei Liao, Chih-Ching Chen, Yuh Chen, Ming-Jiou Yu, Kuo-Jung Lan, Chun-Yu Lin, Shu-Hung ChouOriginal AssigneeMediatek Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (55), Non-Patent Citations (7), Classifications (6), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetApparatus for controlling servo signal gains of an optical disc drive and method of the sameUS 8089834 B2Abstract The invention provides an apparatus for controlling servo signal gains of an optical disc drive. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode, at least one AGC loop of the apparatus compensates the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. In a second mode, at least one AGC loop of the apparatus reloads the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.
1. An apparatus for controlling servo signal gains of an optical disc drive, wherein the apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition, comprising:
in a first mode, at least one AGC loop, compensating the gains of the servo signals with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals; and
in a second mode, at least one AGC loop, reloading the previously saved convergence values or pre-determined values as the initial values according to the current operating state immediately after the operating state transition to accelerate the convergence of the servo signals.
a second automatic gain control module, adjusting the gains of the sub-beam servo signals according to a main-beam sub-beam ratio whenever the optical disk drive encounters the operating state transition, wherein the main-beam sub-beam ratio is calculated according to both the reflection signals of the main-beam and a sub-beam reflected from an optical disc.
a main-beam sub-beam ratio generation module, calculating the main-beam sub-beam ratio according to from the reflection signal of the current main-beam and the reflection signal of the current sub-beam to calculate the main-beam sub-beam ratio; and
17. A method for controlling servo signal gains of an optical disc drive, the method comprising:
adjusting a loop ratio of a main-beam to control the gains of a plurality of servo signals whenever the optical disk drive encounters an operating state transition in which the reflectivity of a read portion of an optical disc or the intensity of the main-beam incident to the optical disc is changed, wherein the servo signals control a servo system of the optical disc drive; and
adjusting the gains of the sub-beam servo signals according to a main-beam sub-beam ratio whenever the optical disk drive encounters the operating state transition, wherein the main-beam sub-beam ratio is calculated according to both the reflection signals of the main-beam and the sub-beam reflected from an optical disc.
18. The method as claimed in claim 17, wherein adjusting a loop ration of a main-beam further comprises:
calculating the loop ratio according to a desired target intensity and the reflection intensity of the current main-beam; and
determining the gains of the servo signals according to the loop ratio.
19. The method as claimed in claim 17, wherein adjusting the gains of the sub-beam servo signals further comprises:
calculating the main-beam sub-beam ratio according to the reflection intensity of the current main-beam and the reflection intensity of the current sub-beam; and
determining the gains of sub-beam servo signals for synthesizing the servo signals according to the main-beam sub-beam ratio.
20. The method as claimed in claim 17, wherein the operating state transition occurs whenever an operating state of the optical disc drive is changed, and the operating state comprise a write state in which data is written to the optical disc, a blank state in which blank zone of the optical disc is read, and a data state in which data zone of the optical disc is read.
CROSS REFERENCE TO RELATED APPLICATIONS This application is a Continuation of U.S. application Ser. No. 11/758,082, filed Jun. 5, 2007, which claimed the benefit of U.S. Provisional Application No. 60/803,874, filed Jun. 5, 2006, U.S. Provisional Application No. 60/803,875, filed Jun. 5, 2006, U.S. Provisional Application No. 60/803,887, filed Jun. 5, 2006, U.S. Provisional Application No. 60/810,991, filed Jun. 5, 2006, U.S. Provisional Application No. 60/810,972, filed Jun. 5, 2006, U.S. Provisional Application No. 60/810,989, filed Jun. 5, 2006, U.S. Provisional Application No. 60/811,031, filed Jun. 5, 2006, U.S. Provisional Application No. 60/811,017, filed Jun. 5, 2006, U.S. Provisional Application No. 60/810,990, filed Jun. 5, 2006, and U.S. Provisional Application No. 60/810,898, filed Jun. 5, 2006, which are all incorporated by reference herein.
BRIEF SUMMARY OF THE INVENTION An apparatus for controlling servo signal gains of an optical disc drive is provided. The apparatus adjusts the gains of a plurality of servo signals controlling a servo system of the optical disc drive when the optical disk drive encounters an operating state transition. In a first mode, at least one AGC loop determining the gains of the servo signals is compensated with a selectable bandwidth during a specific period after the operating state transition to accelerate the convergence of the servo signals. Or in a second mode, previously saved convergence values or pre-determined values determining the most possible gains of the servo signals are immediately reloaded to be the initial values of at least one AGC loop after the operating state transition to accelerate the convergence of the servo signals. After reloading of this previously saved convergence values or pre-determined values as the initial values of AGC loops, the requirement for the bandwidth of AGC loops can be not so high.
Another apparatus for controlling servo signal gains of an optical disc drive is provided. The apparatus includes a first automatic gain control module and a second automatic gain control module. The first automatic gain control module adjusts a loop ratio of a main-beam to control the gains of a plurality of servo signals whenever the optical disk drive encounters changes in the reflectivity of an optical disc, wherein the servo signals control a servo system of the optical disc drive. The second automatic gain control module adjusts the gains of the sub-beam servo signals according to a main-beam sub-beam ratio whenever the optical disk drive encounters changes in the reflectivity of an optical disc, wherein the main-beam sub-beam ratio is calculated according to both the reflection signals of the main-beam and a sub-beam reflected from an optical disc.
A method for controlling servo signal gains of an optical disc drive is also provided. The method comprising: adjusting a loop ratio of a main-beam to control the gains of a plurality of servo signals whenever the optical disk drive encounters an operating state transition in which the reflectivity of a read portion of an optical disc or the intensity of the main-beam incident to the optical disc is changed, wherein the servo signals control a servo system of the optical disc drive; and adjusting the gains of the sub-beam servo signals according to a main-beam sub-beam ratio whenever the optical disk drive encounters the operating state transition, wherein the main-beam sub-beam ratio is calculated according to both the reflection signals of the main-beam and the sub-beam reflected from an optical disc.
FIG. 42 is a flowchart of an exemplary automatic control circuit method, in the automatic control circuit in FIG. 39.
Each of the analog adjusting modules 211�218 comprises an amplifier, an analog offset unit, and an Anti-Alias Filter (AAF). For example, the first adjusting module 211 comprises an amplifier 311, an analog offset unit 221, and an AAF 231. Each of the digital adjusting modules 261�268 comprises a digital offset unit. For example, the digital adjusting module 261 comprises a digital offset unit 271.
The analog adjusting modules 211�218 are respectively coupled to the sample and hold units 201�208 for receiving the sampled photo diode signals A-H output from the sample and hold units 201�208 and amplifying the received photo diode signals. The gains of the analog adjusting modules 211�218 are appropriately controlled for increasing signal qualities of the amplified analog photo diode signals.
The analog offset units 221�228 are respectively coupled to the analog adjusting modules 211�218 for receiving the amplified photo diode signals A�H output from the analog adjusting modules 211�218 and offsetting the amplified photo diode signals A�H. The offset values of the analog offset units 221-228 are appropriately controlled so that the analog photo diode signals after being offset can fall within the input signal ranges of the multiplexer 240 and the ADC 250.
Please refer to FIG. 13 again. In the control system 1100 of the multi-buffer architecture mentioned above, the control effort stored in a selected buffer of the buffers 1106-1, 1106-2, 1106-3, . . . , 1106-N will be applied to the DAC 1110 when the state change occurs. However, due to hardware limitations, there may be an unavoidable latency at the output of DAC 1110 while changing the input of the DAC 1110 from control datum of the current state to control datum of the next state. If the latency is too large, the overall system performance will be degraded. Commonly, the latency is introduced due to a specific ADC implementation having a low-pass filter connected to an output of the analog-to-digital converter for stabilizing the analog output fed into the following circuit block (e.g. the target circuit 1102). To solve this problem, the present invention further discloses a mechanism to dynamically control the response speed of the analog output fed into the target circuit 1102. Please refer to FIG. 15, which is a block diagram illustrating an alternative DAC architecture according to an embodiment of the present invention. The DAC 1110 is replaced with the combination including an ADC 1110′, a low-pass filter (LPF) 1302, and a filter controller 1304. The ADC 1110′ is used for receiving the control datum outputted from the multiplexer 1108 and then converting the control datum into an analog control signal. The LPF 1302 is implemented for filtering out high-frequency components in the analog control signal to smooth the analog control signal fed into the target circuit 1102. In this embodiment shown in FIG. 15, the filter controller 1304 is coupled to the LPF 1302, and is configured to output a control signal BW_SW to change a bandwidth of the LPF 1302 when detecting a state transition from a selected operational state to a next selected operational state. Please refer to FIG. 16. FIG. 16 is a timing diagram illustrating the filter bandwidth adjustment controlled by the filter controller 304 shown in FIG. 3. Suppose that the target circuit 1102 is a laser diode of an optical pick-up unit and the current state is a read state. It should be noted that the digital-to-analog converter 1110 used in the above-mentioned embodiments is driven by a fixed clock signal to update its output periodically according to the input digital value received at the time triggered by the clock signal. Therefore, as shown in FIG. 16, at the timing Ta0, the DAC 1110′ reads the control datum DACR1 stored in a selected buffer (e.g. the buffer 1106-1) corresponding to the read state, where the control datum DACR1 is determined by the digital controller 1120 for updating the previous control datum DACR0. At the timing Ta1, the operational state of the target circuit 1102 is changed to a write state from the current read state. The filter controller 1304 is triggered by the state transition, for example, from the state decision signal Sd outputted from the state decision circuit 1104, and the control signal BW_SW is set to a high logic level to switch the LPF 1302 to a high bandwidth mode, thereby allowing the analog output of the DAC 1110′ to reach the desired level rapidly. At the timing Ta2, the filter controller 1304 resets the control signal BW_SW to a low logic level to switch the LPF 1302 back to a low bandwidth mode. It should be noted that after the LPF 1302 enters the low bandwidth mode, the analog output fed into the target circuit 1102 changes smoothly but the signal-to-noise ratio (SNR) is high. Similarly, at the timing Ta3, the operational state of the target circuit 1102 is changed to a read state from the current write state. The filter controller 1304 is triggered by the state transition to make the control signal BW_SW set to a high logic level to switch the LPF 1302 to a high bandwidth mode, thereby allowing the analog output of the DAC 1110′ to reach the desired level rapidly; and at the timing Ta4, the filter controller 1304 resets the control signal BW_SW to a low logic level to switch the LPF 1302 back to a low bandwidth mode. In addition, as shown in FIG. 16, the DAC 1110′ is also configured to change its analog output in spite of the updating timing defined by the clock signal inputted thereto. For example, at the timing Ta1 which is prior to the normal updating timing Ta1′, the DAC 1110′ changes its updating timing in response to the state transition; similarly, at the timing Ta3 which is prior to the normal updating timing Ta3′, the DAC 1110′ changes its updating timing in response to the state transition, thereby also decreasing the latency and increasing the response speed. Any ADC architectures using one or both of the aforementioned latency reduction techniques all fall within the scope of the present invention.
P w P p ⁢ ⁢ k = Δ ⁢ ⁢ I 1 ′ Δ ⁢ ⁢ I 1 = ( Δ ⁢ ⁢ I 1 ″ + Δ ⁢ ⁢ I w ′ ) ( Δ ⁢ ⁢ I 1 ″ + Δ ⁢ ⁢ I w ′ + Δ ⁢ ⁢ I pk ′ ) Equation ⁢ ⁢ ( 1 ) In Equation (1), the parameter ΔI1′ is meant to be an amount of current shown in FIG. 21 and can be calculated according to the slope Gw and target read power level Pr, and the amount of current ΔIw′ can be derived according to the driving signal Sw′. Since the target peak power level Ppk and the target write power level Pw are known and the amounts of current ΔI1′ and ΔIw′ are calculated, the amount of current ΔIpk′ can also be calculated by Equation (1). That is, the peak power control value can be derived if the write power control value and an adjusting value corresponding to the amount of current ΔI1′ are determined, since a conversion relation between driving signals corresponding to the above-mentioned amounts of current and control values is almost linear. Thus, the adjusting value corresponding to the amount of current ΔI1′ can be calculated according to the amount of current ΔI1′ and the conversion relation between the driving signals and control values. The peak power control value is determined once the adjusting value is calculated, and then the APC system 2502 can control the actual peak power level at the target peak power level Ppk correctly according to the peak power control value. In this embodiment, the peak power control value is equal to the value of the write power control value plus the determined adjusting value. Even though a required driving current passing through the LD D1 may be a little different due to the above-mentioned reasons (e.g. a change of the temperature of the LD D1 or the other factors), the APC system 2502 can still control the actual peak power level at the target peak power level Ppk effectively by deriving a new adjusting value according to the target read power , and a new calculated slope (usually, when the required driving current is different, there is also some possibility that the write power control value is changed and therefore it is necessary to calculate a new slope).
The new slope can be calculated according to the target read power level , the target write power level Pw, and the changed write power control value.
In Equation (2), the parameter X′ is just the ratio (Ppk-Pw)/Pw. Parameters Gpkadj, Gpkldd, Gwadj, Gwldd, and Gs are gains of the gain amplifiers GPK_ADJ, GPK_LDD, GW_ADJ, GW_LDD, Gsum respectively. From Equation (2), the gain Gpkadj of the adjustable gain amplifier GPK_ADJ can be determined since the gain Gpkadj depends on the parameters R, Gpkldd, Gwadj, and Gwldd.
Of course, it will be obvious that the gains Gpkadj and Gwadj are the same and the adjustable gain amplifiers GPK_ADJ and GW_ADJ can therefore be removed from the APC system 2502 without incurring errors if the gains Gpkldd and Gwldd are identical and the target write power level Pw is half of the target peak power level Ppk. In another embodiment, the amount of current ΔIpk′ corresponding to the peak power control value can equivalently be derived by directly dividing the target write power level Pw by the slope Gw, without calculating the amount of current ΔI1′ corresponding to the adjusting value. That is, the peak power control circuit 2505 can also generate the peak power control value according to the target write power level Pw and the slope Gw, without calculating the adjusting value. This also falls within the scope of the present invention.
In other embodiments, the peak power control circuit 2505 can further multiply the above-mentioned peak power control value by the parameter X′ (i.e. the ratio (Ppk-Pw)/Pw) to output an amplified control value to the DAC 2510. Thus, the digital gain amplifier GRATIO in the APC system 2502 is not required and is excluded from the APC system 2502. The relation between total gains of the write channel and the peak channel is illustrated as the following equation:
In this embodiment, the ADC device 4403 and the first LPF 4404 a are clocked or synchronized by a clock generator 4405 of clock rate (or frequency) CK1. Therefore, the first sampling rate of the first LPF 4404 a is CK1, and the ADC device 4403 samples the servo signals by the first sampling rate CK1. A frequency divider 4406 divides clock signal of the clock generator 4405 by the factor N, and outputs a divided clock signal of clock rate CK2 ( equal ⁢ ⁢ to ⁢ ⁢ CK ⁢ ⁢ 1 N ) to the second LPF 4404 c. Therefore, the second sampling rate of the second LPF 4404 c is CK2. It is noted that the first LPF 4404 a can be an anti-alias filter for the second LPF, and the second LPF 4404 c is designed to have a low corner frequency corresponding to the desired frequency (or bandwidth) of the HPF 4404. In addition, both the first and second LPFs 4404 a and 4404 c can have unit DC gain. In order to not lose bit information, two cascade-coupled LPFs implement the HPF, according to this embodiment. Therefore, a high pass filter with a lower frequency (or bandwidth) is obtained without losing too much bit information.
In this embodiment, the ADC device 4503 and the first LPF 4504 a are clocked or synchronized by a clock generator 4505 of clock rate CK1. Thus, the first sampling rate of the first LPF 4504 a is CK1, and the ADC device 4503 samples the servo signals using the first sampling rate CK1. A first frequency divider 4506 divides clock signal of the clock generator 4505 by the factor N, and outputs a divided clock signal of clock rate CK2 ( equal ⁢ ⁢ to ⁢ ⁢ CK ⁢ ⁢ 1 N ) to the second LPF 4504 c. A second frequency divider 4507 divides clock signal output from the first frequency divider 4506 by the factor M, and output a divided clock signal of clock rate CK3
( equal ⁢ ⁢ to ⁢ ⁢ CK ⁢ ⁢ 2 M ) to the third LPF 4504 g. Therefore, the second and third sampling rate of the second and third LPFs 4504 c and 4504 g are CK2 and CK3 respectively. It is noted that the first and second LPF 4504 a and 4504 c can be anti-alias filters, and the third LPF 4504 g is designed to have a low corner frequency corresponding to the desired frequency (or bandwidth) of the HPF 4504. In addition, the first to third LPFs 4504 a, 4504 c and 4504 g can have unit DC gains. A low corner frequency needs a small coefficient for a LPF. In order to not lose bit information, three cascade-coupled LPFs are used to implement the HPF, according to this embodiment. Thus, a high pass filter with a lower frequency (or bandwidth) is obtained, without losing too much bit information.
18 KHz 0.03699
14 KHz 0.02970
500 Hz 0.00100
250 Hz 8K
500 Hz 8K
16 KHz 16K
18 KHz 18K
VMAX=max(PRE_MAX1,PRE_MAX2, . . . , PRE_MAXn−1,CUR_MAX) (3) VMIN=max(PRE_MIN1,PRE_MIN2, . . . , PRE_MINn−1, CUR_MIN) (4)
As shown in FIG. 35, an on-track signal TRON is additionally presented. The on-track signal TRON serves as a system flag for indicating if the current operation mode is an on-track mode or a track jumping (track-seeking) mode. For example, when the on-track signal TRON is maintained at a high logic level, it means that the optical pick-up unit is operated under the on-track mode; however, when the on-track signal TRON has a transition from a high logic level to a low logic level, it means that the optical pick-up unit enters the track-jumping mode, and when the on-track signal TRON has a transition from a low logic level to a high logic level, it means that the optical pick-up unit leaves the track-jumping mode. Referring to FIG. 35, the track-jumping mode is activated during an operational period from Tb1 to Tb1′. At time T1, a new track jumping operation starts. Therefore, when the on-track signal TRON has a transition from a high logic level to a low logic level at time Tb1, the initial value controller 5112 is enabled to control the initial value of the slicer level Lref. When a next track jumping operation is activated, the target peak value VMAX and the target bottom value VMIN obtained due to an edge of the TEZC signal Sref occurring at time T1′ are used for controlling the initial value of the slicer level Lref.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5212675 *Jan 23, 1992May 18, 1993Pioneer Electronic CorporationApparatus for detecting position of light spotUS5699334Jan 22, 1996Dec 16, 1997Matsushita Electric Industrial Co., Ltd.Control devices for optical disk based on driving signal saturationUS5703848 *Apr 5, 1994Dec 30, 1997Hewlett-Packard CompanyOff track detection system for ruggedized optical disk driveUS5768227 *Sep 8, 1997Jun 16, 1998Canon Kabushiki KaishaOptical information recording and or reproducing apparatus and method for irradiating a recording medium having a plurality of information tracksUS5805715Jun 29, 1994Sep 8, 1998Samsung Electronics Co., Ltd.Method and apparatus for compensating multi-resolution linear distortionUS5835043Apr 22, 1997Nov 10, 1998Sony CorporationSignal processing apparatus, signal recording apparatus, and signal reproducing apparatusUS5915028Sep 8, 1995Jun 22, 1999Robert Bosch GmbhAmplitude demodulatorUS6081485Nov 10, 1998Jun 27, 2000Teac CorporationOptical disc accessing apparatus capable of preventing error in the mirror signalUS6091678Jan 5, 1998Jul 18, 2000Hitachi, Ltd.Method and apparatus for detecting position of alternated land and groove of information recording mediumUS6392967Sep 11, 1998May 21, 2002Sony Precision Engineering Center (S) Pte. Ltd.Apparatus for measuring characteristics of optical disc systems and methodUS6424687Mar 15, 1999Jul 23, 2002Cirrus Logic, Inc.Method and device for alignment of audio data frames using interpolation and decimationUS6590843Jun 1, 1999Jul 8, 2003Texas Instruments IncorporatedDVD radial runout cancellation with self-calibrationUS6680644Sep 26, 2001Jan 20, 2004Siemens Information & Communication Networks, Inc.Digital interpolation window filter for phase-locked loop operation with randomly jittered reference clockUS6731586Mar 26, 2001May 4, 2004Samsung Electronics Co., Ltd.Apparatus for and method of controlling auto laser diode powerUS6735162Jun 13, 2001May 11, 2004Lsi Logic CorporationApparatus and method providing a mirror averaging function to generate a mirror signal from optical data on an optical discUS6762982May 23, 2001Jul 13, 2004Lsi Logic CorporationApparatus and method of interrupt detection in an optical disc environmentUS6834035Sep 29, 2000Dec 21, 2004Matsushita Electric Industrial Co. Ltd.Digital reproduced signal processing deviceUS6891787Aug 22, 2000May 10, 2005Sanyo Electric Co., Ltd.Apparatus for recording/reproducing signal on/from optical diskUS6898223Feb 28, 2002May 24, 2005Samsung Electronics Co., Ltd.Apparatus for and method of controlling output of a laser diodeUS6967906May 16, 2003Nov 22, 2005Samsung Electronics Co., Ltd.Circuit and method for detecting mirror signal for optical disc apparatusUS7035187Dec 13, 2002Apr 25, 2006Via Technologies, Inc.Apparatus and method for generating RFZC signal for optical systemsUS7474235Jun 5, 2007Jan 6, 2009Mediatek Inc.Automatic power control system for optical disc drive and method thereofUS20010006494Dec 22, 2000Jul 5, 2001Sang On ParkApparatus and method for controlling tracking for optical recording/reproducing apparatusUS20010024459Mar 26, 2001Sep 27, 2001Seo Jin-GyoApparatus for and method of controlling auto laser diode powerUS20020196717 *Apr 1, 2002Dec 26, 2002Naruhiro MasuiSignal processing method and signal processing apparatusUS20030021208Jul 25, 2002Jan 30, 2003Youichi OguraDigital data reproduction apparatusUS20030185260Dec 17, 2002Oct 2, 2003Samsung Electronics Co., Ltd.Laser diode driver and driving method for controlling auto laser power, optical pickup device, and optical recording/reproducing apparatus using the sameUS20040190397 *Sep 17, 2003Sep 30, 2004Matsushita Electric Industrial Co., Ltd.Apparatus and method for tracking controlUS20040199271Mar 30, 2004Oct 7, 2004Yasushi SaitoAutomatic gain adjustment device and automatic gain adjustment methodUS20040233826May 18, 2004Nov 25, 2004Akihiro SuganoLaser power control device, information recording apparatus, optical disk apparatus, laser power source drive current value determining method, information recording method, optical disk recording methodUS20040252599May 20, 2004Dec 16, 2004Sanyo Electric Co, Ltd.Offset adjusting circuit for optical disc and offset adjusting methodUS20040257946Nov 7, 2003Dec 23, 2004Chao-Ming HuangDynamic radio frequency ripple signal compensator of an optical storage systemUS20050006882Jul 10, 2003Jan 13, 2005Yunzhang WangAir bag and method for making an air bagUS20050185559Feb 1, 2005Aug 25, 2005Kabushiki Kaisha ToshibaOptical disk device, reproduction method of information on optical disk, and optical diskUS20050270918May 27, 2005Dec 8, 2005Kuang-Yu YenOptical disc drive capable of generating digital servo control signals and method thereofUS20050280569Jun 14, 2005Dec 22, 2005Samsung Electronics Co., Ltd.Analog baseband processor and method of processing analog baseband for use in multimode communication systemUS20050281300Aug 15, 2004Dec 22, 2005Yung-Chih LiLaser power controller and method for performing auto power controlUS20060018229Jul 12, 2005Jan 26, 2006Sony CorporationClock generation circuit and optical disk apparatusUS20060193053 *Jan 30, 2006Aug 31, 2006Tdk CorporationDiffraction grating, light-receiving element, and optical head and optical recording/reproducing apparatus utilizing themUS20060267825Feb 28, 2006Nov 30, 2006Yutaka YamamotoHigh frequency compensator and reproducing deviceUS20070019772Sep 29, 2006Jan 25, 2007Applied Micro Circuits CorporationTimeshared jitter attenuator in multi-channel mapping applicationsUS20070047635Aug 24, 2005Mar 1, 2007Stojanovic Vladimir MSignaling system with data correlation detectionUS20070070853Mar 30, 2005Mar 29, 2007Kenji KoishiInformation recording method, information recording apparatus and information recording mediumUS20070133831Sep 5, 2006Jun 14, 2007Samsung Electronics Co., Ltd.Apparatus and method of reproducing virtual sound of two channelsUS20080033695Oct 17, 2005Feb 7, 2008Nsk LtdAbnormality Diagnosing System For Mechanical EquipmentUS20080219116Jun 17, 2005Sep 11, 2008Kenji NarumiOptical Information Recording Method, Optical Information Recording Apparatus, and Optical Information Recording MediumUSRE40822Aug 23, 2007Jul 7, 2009Ronnie LaiCalibration method for slice level of zero cross signal and method of producing track-crossing signalCN1319841AMar 23, 2001Oct 31, 2001三星电子株式会社Device and method for automatically controlling laser diode powerCN1402231ASep 29, 2002Mar 12, 2003威盛电子股份有限公司Read-write head output power control method for CD machineCN1448929AOct 10, 2002Oct 15, 2003三星电子株式会社Laser diode driver, optical pickup device, and optical recording/reproducing apparatus using the sameCN1573973AMay 10, 2004Feb 2, 2005三洋电机株式会社Offset adjusting circuit for optical disc and offset adjusting method, integrated circuit, optical discCN1604208ASep 15, 2004Apr 6, 2005株式会社东芝Optical disk apparatus and laser control methodTW227017B Title not availableTW476935B Title not availableWO2004015988A1Aug 6, 2003Feb 19, 2004Canopus Co LtdImage signal processing device and image recording output device* Cited by examinerNon-Patent CitationsReference1English language translation of abstract of CN 1319841 (published Oct. 31, 2001).2English language translation of abstract of CN 1402231 (published Mar. 12, 2003).3English language translation of abstract of CN 1448929 (published Oct. 15, 2003).4English language translation of abstract of CN 1573973 (published Feb. 2, 2005).5English language translation of abstract of CN 1604208 (published Apr. 6, 2005).6English language translation of abstract of TW 227017 (published Jan. 21, 2005).7English language translation of abstract of TW 476935 (published Feb. 21, 2002).Classifications U.S. Classification369/44.29, 369/44.28International ClassificationG11B7/00Cooperative ClassificationG11B7/0903, G11B7/0941European ClassificationG11B7/09KLegal EventsDateCodeEventDescriptionJan 19, 2011ASAssignmentOwner name: MEDIATEK INC., TAIWANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LIAO, CHIA-WEI;CHEN, CHIH-CHING;CHENG, YUH;AND OTHERS;SIGNING DATES FROM 20070309 TO 20070313;REEL/FRAME:025663/0284RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About 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