Adaptive phase discovery

摘要

In an adaptive phase discovery system a first audio signal is received via a first microphone and a second signal is received via a second microphone. Corresponding audio frames of the first and second signals are each transformed into the frequency domain and a plurality of frequency sub-bands are generated. A phase is determined for each frequency sub-band in each signal. Instantaneous phase differences are determined between the signals at each of the frequency sub-bands. Lower frequency instantaneous phase differences are filtered over time to determine current phase differences at lower frequencies. When SNR is high in lower frequency sub-bands, lower frequency sub-band phase differences are tracked to the higher frequency sub-bands. The tracked higher frequency phase differences are filtered over time to determine phase differences for the current frame. The phase differences may be used to rotate phases in each sub-band and sum signals and/or to reject off-axis signals.

主权项

1. A method for determining phase difference, the method comprising:
determining a phase of a first signal and a phase of a second signal; determining an instantaneous phase difference between said first signal and said second signal based on said phase of said first signal and said phase of said second signal; filtering said instantaneous phase difference over time for frequencies below a specified frequency threshold; estimating a phase difference between said first signal and said second signal at one or more frequencies above said specified frequency threshold, based on said filtered phase difference of frequencies below said specified frequency threshold; and detecting presence of an audio signal based on signal to noise ratio, signal level or signal power level at one or more frequencies below said specified frequency threshold and including said audio signal in said filtering said instantaneous phase difference over time for frequencies below said specified frequency threshold.