| 摘要 |
PROBLEM TO BE SOLVED: To provide a howling canceller equipped with an adaptive filter that distinguishes a sustained sound of a musical sound with constant frequency from a howling, and does not attenuate an input signal by the musical sound. SOLUTION: A waveform analyzing unit 8 performs a fast Fourier-transform on an audio signal inputted from a microphone 1 to detect a peak frequency and a harmonic frequency. Then, it compares them with a howling waveform pattern stored in a waveform storage unit 9. A cross-correlation function of both waveforms is calculated. When a cross-correlation value is a predetermined threshold or more, it is determined that the audio signal is a howling. When the value is the threshold or less, it is determined that the audio signal is not a howling. When the audio signal is determined not to be a howling, the adaptive filter 7 is instructed to suspend adaptive processing. This enables the suppression of only howling without canceling the sustained sound of a musical sound with constant frequency. COPYRIGHT: (C)2006,JPO&NCIPI |
