US 11,722,819 B2
Adaptive feedback cancelation and entrainment mitigation
Sarmad Aziz Malik, Redmond, WA (US); and Nils Thomas Fritiof Lunner, Redmond, WA (US)
Assigned to Meta Platforms Technologies, LLC, Menlo Park, CA (US)
Filed by META PLATFORMS TECHNOLOGIES, LLC, Menlo Park, CA (US)
Filed on Sep. 21, 2021, as Appl. No. 17/481,170.
Prior Publication US 2023/0090315 A1, Mar. 23, 2023
Int. Cl. H04R 3/00 (2006.01); H04R 3/02 (2006.01); H04R 1/02 (2006.01)
CPC H04R 3/02 (2013.01) [H04R 1/025 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An audio system comprising:
a reference microphone configured to receive a reference audio signal;
a speaker configured to emit sound based on a speaker signal;
an error microphone configured to receive the sound emitted by the speaker and generate an error signal;
an audio controller configured to:
generate, based on the reference audio signal received by the reference microphone, a reference signal;
reduce feedback in the speaker signal provided to the speaker by feedforward processing the reference signal;
mitigate entrainment in the speaker signal by processing the error signal and the speaker signal in a frequency domain using state space filtering, wherein processing the error signal and the speaker signal comprises separating the error signal and the speaker signal into a plurality of frequency bands;
update the error signal by subtracting, based on the state space filtering, a feedback cancelation signal generated by the audio controller from an updated reference signal outputted by the reference microphone; and
generate an updated speaker signal by feedforward processing the updated error signal.