Patent ID: 7480224
Filing Date: 2009-01-20
Classification: G11B

Abstract:
1. In an optical information reproducing system, a decoding apparatus for decoding a signal retrieved by said system from an optical information recording medium, N legal codes being predetermined, wherein N is a natural number, said decoding apparatus comprising: an Analog-to-digital converter (ADC) for converting the retrieved signal into a data stream; a Viterbi decoder, coupled to an output of the ADC, for decoding, according to N reference levels and a level of the data stream, the data stream into a digital data, wherein each of the N reference levels corresponds to one of the N legal codes; a binary array for decoding the digital data decoded by the Viterbi decoder into one of the N legal codes; a delay device, coupled to the output of the ADC, for delaying the data stream, and outputting a delayed data stream corresponding to the data stream; a reference level adjusting device, respectively coupled to an output of the Viterbi decoder and an output of the delay device, for receiving the code relative to the data stream and the delayed data stream corresponding to the data stream, adjusting the N reference levels in accordance with an algorithm including a conversion-speed-adjusting coefficient, and outputting the N reference levels to the Viterbi decoder; a conversion-speed-adjusting coefficient generating device for generating the conversion-speed-adjusting coefficient in response to at least one condition signal, and outputting the conversion-speed-adjusting coefficient to the reference level adjusting device; and at least one condition detector which each is in charge of detecting a respective condition associated with the retrieved signal and outputs one of the at least one condition signal corresponding to the detected condition to the conversion-speed-adjusting coefficient generating device.