Samsung Electronics Co., Ltd.

Young-wook Jang

Je-Kook Kim

Suk-Jung Lee

Jong-In Kim

Kwan-Ho Kim

Bong-chun Kang

Jong-Jin Lee

Suk-jung Lee

Jeong-Cheol Shin

Hee-Dong Shin

Dae-Woong Kim

Bom-Yun Kim

Je-kook Kim

Je-koonk Kim

A memory controller includes an digitally programmable delay unit having a selectable delay time receiving a read-enable signal and outputting a delayed read-enable signal. The delay time is selected in response to an externally applied delay-control signal. A sampling unit in the memory controller outputs data received from a separate memory, in synchronization with the delayed enable signal. The delay time may be a multiple of the period of a clock signal.

Memory controller

A method and apparatus for detecting a free page of a memory device, and a method and apparatus for decoding an error correction code by using the method and apparatus for detecting a free page are provided. Free page data read from the memory is converted into a converted codeword for inclusion as an element of an error correction code field. The converted codeword is compared to an initially set target codeword to detect an amount of non-identical bits. A page read from the memory is determined to be a free page when the amount of non-identical bits is equal to or less than an initially set threshold value.

Method and apparatus for detecting free page and a method and apparatus for decoding error correction code using the method and apparatus for detecting free page

Provided are a focus search apparatus and method for performing a focus search after moving an optical pickup to a focus-on point according to a signal output from a sine wave generator so that a stable and smooth focus search is performed. In the focus search method, a sine wave is generated in response to a focus search command. The focus search is performed using an optical pickup in response to the sine wave. The optical pickup is driven in response to an amplitude of the sine wave during the focus search and in response to a filtered focus error signal during a focus servo.

Focus search apparatus and method

A signal generator generates a track traversing signal, and a driver causes a pick-up to traverse across tracks of a disc in accordance with the track traversing signal. An error signal generator generates a tracking error signal from the pick-up traversing across the tracks of the disc in accordance with the track traversing signal. A parameter calculator determines a value of a calibration parameter from the tracking error signal that is generated without delay and without signal distortion from low frequency components.

Disc drive calibration with forced track traversing signal

Provided are an apparatus and method for detecting a type of an optical disc inserted into an optical disc system and/or adjusting a track balance in the optical disc system by detecting voltages of a focus error signal and a tracking error signal. For detecting a type of an optical disc inserted into an optical disc system, the apparatus comprising: an analog-to-digital converter that converts a focus error signal into n-bit voltage data; and a duty measurer that compares the n-bit voltage data with a positive noise voltage level and a negative noise voltage level, upcounts by a predetermined value if the n-bit voltage data is higher than the positive noise voltage level or lower than the negative voltage level, and outputs the upcounted result as a duty of the focus error signal.

Apparatus and method for detecting optical disc type and/or adjusting track balance

Optical disc systems and methods for controlling movement of an optical pickup to an innermost perimeter of an optical disc using track information are provided. For example, an optical disc system includes an optical pickup that includes a tracking actuator, a focus actuator, and an objective lens and radiates a laser beam onto the optical disc to detect light reflected from the optical disc. The optical disc system also includes a radio frequency amplifier, a sled motor, a servo driver, and a servo signal processor that includes an optical pickup movement determiner and outputs a servo control signal, the optical pickup movement determiner determining from a track-related signal whether tracks are detected on the optical disc at a current position of the optical pickup and outputting a track determination signal indicating whether the optical pickup has moved to the innermost perimeter of the optical disc, based on the determination result.

Optical disc system and method for controlling movement of an optical pickup to an innermost perimeter of an optical disc using track information

A method and an apparatus for precisely controlling the rotation speed of a spindle motor in an optical system according to a given condition are provided. The method involves counting in response to a clock signal widths of first and second logic states of an input signal, which varies with rotation speed of the spindle motor, when an operation control command is issued, comparing a predetermined reference value with a count value for one check cycle, and outputting the comparison result; and controlling the constant linear velocity of the spindle motor in response to the comparison result.

Method and apparatus for controlling constant linear velocity of spindle motor using mirror signal

A brake signal generating circuit and method for improving the efficiency of a lens brake in an optical disc reproducing system are provided. The brake signal generating circuit includes: a brake signal generator which receives a mirror signal that detects the track movement of a main beam and generates a first brake signal or a second brake signal for selecting predetermined operation mode signals in response to a first brake selection signal; a first operation mode generator which generates a processing value of the gain and phase of a tracking error as a first operation mode signal in response to a predetermined first control signal; a second operation mode generator which generates a correction value of a tracking loop offset as a second operation mode signal in response to a second control signal; a third operation mode generator which generates a value obtained by multiplying a value of the first operation mode signal by a predetermined value K, where Kis a non-zero real number, as a third operation mode signal; a fourth operation mode generator which generates as a fourth operation mode signal a value obtained by subtracting the value of the first operation mode signal from a value of the second operation mode signal, multiplying the result of the subtraction by the predetermined value K, and adding the value of the second operation mode signal to the product; a fifth operation mode generator which generates a predetermined reference voltage as a fifth operation mode signal; and a switch unit which outputs one of the first through fifth operation mode signals in response to the first or second brake signal and second through fourth brake selection signals. The amount of braking is inverted in accordance with the amount of error in a track deviation direction and multiplied by a gain factor to improve the brake efficiency. In addition, the settling time after a track jump is reduced, the data access can be faster, and the unstable state, for example, due to track skipping, can return to the original stable state quickly.

Brake circuit for three-beam optical tracking system

Method and apparatus for controlling the light power of an optical disk system, and optical disk system having the same are provided. The optical disk system includes a microcontroller for controlling the operation of the optical disk system, a light power adjusting apparatus for generating a light quantity control signal for controlling the quantity of light emitted from the optical disk, and an optical pickup device for adjusting the quantity of light emitted from the optical disk in response to the light quantity control signal. The method includes the steps of converting E and F beam signals used for generating a tracking error signal into the form of voltage and synthesizing the converted E and F beam signals to obtain a tracking sum signal; maintaining the light power of the light emitting diode when the level of the tracking sum signal is the same as that of a reference signal; decreasing the light power of the light emitting diode, corresponding to the difference between the tracking sum signal and the reference signal, when the level of the travel sum signal is higher than that of the reference signal; and increasing the light power of the light emitting diode, corresponding to the difference between the tracking sum signal and the reference signal, when the level of the travel sum signal is lower than that of the reference signal. The progress of the method returns back to the stop of obtaining a tracking sum signal after increasing or decreasing the light power. Accordingly, the quantity of light reflected from the an optical disk can be constantly maintained.

Method and apparatus for controlling light power of optical disk system, and optical disk system having the same

In an apparatus and a method for correcting asymmetry in an optical disk reproduction system, an analog RF signal is received from an optical diode and an asymmetry-corrected signal is output as a digital EFM signal. The apparatus includes envelope detectors for detecting upper and lower envelopes of the RF signal, a level controller for controlling the level of the sum of the upper envelope and the lower envelope and for outputting signal having the controlled level, and a comparator for comparing the level of the signal output from the level controller with the level of the RF signal and for outputting the comparison result as the digital EFM signal.

Apparatus and method for correcting asymmetry in an optical disk reproduction system

Apparatus and method for correcting asymmetry of optical disk reproducing system

A tracking servo control apparatus for muting a tracking error signal when a mirror signal is generated, in an optical disk system, such as a compact disk player or a digital video disk, compensates for tracking gain and phase according to the tracking error signal. The apparatus includes a mirror setting unit for receiving the generated mirror signal and for generating a mirror signal by defining the mirror signal to predetermined minimum and maximum time intervals, a switch for outputting a muted tracking error signal while the defined mirror signal is activated, and otherwise, outputting the tracking error signal, and a tracking gain/phase compensator for receiving the output signal from the switch and compensating for the tracking gain and phase. Thus, the system can be stabilized by muting a tracking servo loop according to a mirror signal whose pulse width is defined to a predetermined window section.

Tracking and focusing control apparatus in an optical disk system

An optical signal conversion apparatus in a compact disk player detects peaking in an RF signal read from a disk and compensates to reproduce a stable conversion signal, for example an EFM signal. In the optical signal conversion apparatus, a peaking prevention portion detects peaking of the RF input signal and outputs a predetermined reference voltage, if the peaking is detected, or alternately the input signal, if the peaking is not detected. A waveform processing portion extracts a high frequency component from the signal output from the peaking prevention portion, slices the extracted signal as a predetermined level, and outputs the sliced signal.

Growing community of inventors

Yongin, South Korea

Young-wook Jang