A method and device for detecting a peak which is substantially the same as the actual peak are disclosed. In one embodiment, the device includes a filter, a shift register, a controller and a digital interpolator. The filter is configured to receive a plurality of signal samples and the shift register, which is coupled with the filter, has multiple registers. The shift register is configured to receive the plurality of signal samples and to shift the plurality of signal samples through the registers. The controller is coupled with the shifter register and is configured to detect a zero-crossing event in the signal samples. The digital interpolator is coupled with the controller and configured to perform a binary search to identify a peak substantially the same as the actual peak.