Patent ID: 8494178

Claim:
A digital signal processor for avoiding audio feedback, the digital signal processor comprising: an audio input receiver; a first filter bank, wherein the first filter bank comprises interleaved band-pass filters and band-stop filters; a power spectrum generator to generate a power spectrum of an audio input signal, the audio input signal including a primary acoustic energy; a spectral density analyzer that detects whether the primary acoustic energy of the audio input signal coincides with a band-stop filter in the first filter bank; and a filter inverter, wherein: if the spectral density analyzer determines that the primary acoustic energy of the audio input signal coincides with the band-stop filter in the first filter bank, the filter inverter inverts the first filter bank, and if the spectral density analyzer determines that the primary acoustic energy of the audio input signal does not coincide with the band-stop filter in the first filter bank, the filter inverter does not invert the first filter bank; and a frequency modifier, wherein the frequency modifier modifies at least one passband of the filtered audio input signal output by the first filter bank to fall at least partially within a portion of a bandwidth of a band-stop filter in the first filter bank.