SIGNAL PROCESSING CIRCUIT AND INTEGRATION CIRCUIT

PROBLEM TO BE SOLVED: To provide a signal processing circuit which increase the speed of processing servo signals. SOLUTION: A servo circuit 20b processes servo signals RD. The second AGC servo signals RD is inputted and amplified. The second analog filter 32 eliminates high-frequency components. A peak detecting circuit 33 detects the information which shows the start of sector from the servo signals RD. A zero- cross detecting circuit 34 generates clock signals CK based on the servo signal RD read from each of region 85a to 85d. A counter 35 outputs a main charge control signal CHG or a main discharge control signal CRS. A counter 35 outputs any one of the first to fourth charge control signals, STA to STD, in response to a servo strobe signal STR and a clock signal CK. An integration circuit 36 holds the integration value of the servo signal of each of region 85a-85d based on each charge- and discharge-control signal as charge voltage.