Patent ID: 7519193

Claim:
A hearing aid circuit that provides amplification along a feedforward path in an environment subject to hearing aid feedback, the hearing aid circuit comprising: a phase shifter that is in the feedforward path and that has a phase shifter input, a phase shifter output and a control input, the phase shifter introducing a temporary phase shift for a time duration along the feedforward path; a summing junction that provides a summing junction output that couples to the phase shifter input; a correlation detector that detects correlation at the feedforward path and that provides a correlation output to the control input; a phase measurement circuit measuring a measured phase shift along the feedforward path in response to the temporary phase shift, the phase measurement circuit providing a phase measurement output; and an internal feedback processor that receives the phase measurement output, the internal feedback processor adjusting internal feedback coupled to the summing junction as a function of the phase measurement to suppress coupling of the hearing aid feedback along the feedforward path.