Patent ID: 7215632
Filing Date: 2007-05-08
Classification: G11B

Abstract:
1. A signal processing apparatus for reproducing information recorded on an information recording medium, comprising: a gain offset unit for giving a gain and a DC offset to an inputted reproduction signal, wherein the gain is based on an inputted gain control signal and the DC offset is based on an inputted offset control signal; an A/D converter for receiving the output of the gain offset unit, sampling the input signal with a clock having a predetermined clock cycle T, and analog-to-digital converting the signal, thereby to output sampling data; a peak detector for receiving the output of the A/D converter, and performing peak detection with a clock having a cycle that is m times as long as the clock cycle T, wherein m is a positive integer; a bottom detector for receiving the output of the A/D converter, and performing bottom detection with a clock having a cycle that is n times as long as the clock cycle T, wherein n is a positive integer; an amplitude detector for receiving the output of the peak detector and the output of the bottom detector, and calculating a signal amplitude of the input to the A/D converter as an amplitude information signal; an offset detector for receiving the output of the peak detector and the output of the bottom detector, and calculating a signal offset of the input to the A/D converter as an offset information signal; and a controller for performing gain control and offset control of the gain offset unit based on the amplitude information signal and the offset information signal, A/D controller being able operable to hold the control operation of the controller or change the control speed of the controller according to an inputted hold signal; wherein the signal amplitude and offset of the input to the A/D converter are kept approximately constant regardless of local fluctuations in the inputted reproduction signal.