Patent ID: 6836511
Filing Date: 2004-12-28
Classification: G11B,H04L

Abstract:
A digital reproduced signal processing apparatus for reading out a recorded signal on a recording medium of a digital recording apparatus of high frequency cutoff type, comprising:a read head for reading out the recorded signal and releasing it as an analog reproduced signal; a low-pass filter for removing high frequency noise from the analog reproduced signal; an analog/digital converter for converting the analog reproduced signal filtered by said low-pass filter to a digital reproduced signal; an FIR filter for filtering the digital reproduced signal with use of an adaptive equalization coefficient; an adaptive equalization coefficient setting device for equalizing the impulse response of the digital reproduced signal with the impulse response characteristic of a partial response defined by predetermined coefficients (a,b,b,a) and determining the adaptive equalization coefficient to release the digital reproduced signal filtered by said FIR filter as an equalized digital reproduced signal; a phase comparator for detecting a phase error signal from the digital reproduced signal or the equalized digital reproduced signal; a partial response temporal judgment device responsive to the output signal of said FIR filter for producing and feeding a temporal data judgment signal to said adaptive equalization coefficient setting device and said phase comparator; a Viterbi decoder for decoding the equalized digital reproduced signal released from said FIR filter as a data for judgment; a loop filter for filtering the phase error signal detected by said phase comparator; a digital/analog converter for converting the filtered phase error signal to an analog signal; and a voltage-controlled oscillator controlled by the output signal of said digital/analog converter for oscillation to produce and feed a clock signal to said Viterbi decoder.