Amplitude detecting circuit

摘要

An amplitude detecting circuit (1) comprises a simple digital filter (2) having a structure corresponding to a part where the energy is concentrated in the full impulse response of a signal processing digital filter (3). Concretely, for example, the amplitude detecting circuit (1) (simple digital filter (2)) comprises only four central taps having coefficients of large absolute values and considerably affecting on the output amplitude among sixteen taps of the signal processing digital filter (3). By the amplitude detecting circuit (1), the amplitude of an output signal of the signal processing digital filter (3) can approximately be detected.