Speech-Pass Filter

A speech-pass filter circuitry is shown in the the schematic diagram below. This speech circuit is useful in an application when the frequency spectrum of the signal should be limited to contain only speech (human voice) information. Voice recording or radio broadcasting is some example of such application. Corner frequencies of 300 and 3000 Hz is provided by high pass and low pass filters in cascade for limiting audio bandwidth to speech frequencies. The bode profile is -40 dB per decade roll-off beyond corners. Input to output gain is 1.