摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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 K1, where K1 is 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 K1, 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.
摘要:
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.
摘要:
An optical disk reading apparatus and method compensate for errors in the full period of an EFM signal. An RF amplifier converts an optical signal reflected from an optical disk into an analog electrical signal. A signal converter converts the analog signal into a digital signal which is modulated to provide an EFM signal. A full period compensating portion compensates for full period errors in the EFM signal and outputs the error compensated EFM signal. An error correcting portion corrects the errors of the compensated EFM signal using an error correction code. Image quality is improved by removing the full period errors.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.