An analog signal processor for hard disk drive servo is described. It performs servo demodulation by means of median peak detection which provides immunity against additive as well as multiplicative noise from the medium, unlike conventional methods. A novel circuit configuration has been employed to implement the median peak detector in an area and power efficient manner. The entire servo processor that includes the demodulator and 10 b A/D and D/A converters has been integrated into a single CMOS integrated circuit.