Patent ID: 7366491
Filing Date: 2008-04-29
Classification: H04B

Abstract:
1. A noise cancel circuit for removing noise components in an input audio signal, comprising: an LPF for blocking a sub-signal and a pilot signal in a high frequency band of the input audio signal and passing only a main signal of the input audio signal; an interpolation circuit for interpolation processing on the main signal output from the LPF, a noise detection circuit for detecting the noise portion of said input audio signal, a timer for starting counting in response to an output signal from the noise detection circuit and generating a switching signal during a predetermined period of time while counting is performed; and a selection circuit for selecting one of output signals from a delay circuit and the interpolation circuit in accordance with the switching signal, thereby serving to replace the noise portion of said input audio signal with an output signal from said interpolation circuit according to the output signal from said noise detection circuit and outputting a signal subjected to interpolation processing in its noise portion without adding high frequency components removed from the input audio signal.