Patent ID: 8346311

Claim:
An audio signal processing apparatus comprising: a band signal component extraction unit including a filter designed to extract a signal waveform in a predetermined frequency band from an audio signal input by audio collection means configured to collect at least an outgoing call audio upon an audio phone call, and a first envelope detector configured to detect an envelope of a signal waveform after pass of the filter and to output the signal waveform after the envelope detection as signal components in the predetermined frequency band; a stationary signal component extraction unit configured to extract at least a stationary signal component from the signal components extracted by the band signal component extraction unit; a signal adjustment unit provided with a level adjustment function of adjusting an output signal level with respect to an input signal level and an input and output characteristics change function for changing the input and output characteristics on the basis of a control signal when performing the level adjustment in the level adjustment function, and configured to set an incoming call audio signal upon the audio phone call as the input signal; and a control signal generation unit configured to generate the control signal for changing the input and output characteristics of the signal adjustment unit by using at least the stationary signal component extracted by the stationary signal component extraction unit wherein the stationary signal component extraction unit includes a mute unit configured to mute the signal waveform after the envelope detection and a mute control unit configured to cancel mute of the mute unit when a signal level of the signal waveform after the envelope detection exceeds a predetermined threshold and also this state carries on for a predetermined period of time and to enable the mute of the mute unit when the signal level dips from the predetermined threshold after the mute cancellation, and the control signal generation unit uses at least the stationary signal component composed of a signal waveform output from the mute unit to generate the control signal.