Method and apparatus for a frequency domain echo suppression filter

A method of suppressing residual frequency components of a reference signal, from a least-mean-squared (LMS) filtered signal carrying said residual frequency components of the reference signal, the method comprising:

• dividing a magnitude of the frequency domain representation of the reference signal by a magnitude of the frequency domain representation of the LMS-filtered signal to obtain a frequency domain ratio of the frequency domain representation of the reference signal to the frequency domain representation of the LMS-filtered signal;
• and
• converting to the time domain, the frequency domain ratio of the frequency domain representation of the reference signal to the frequency domain representation of the LMS-filtered signal to produce a time domain, filter coefficient signal;
• and
• providing the time domain filter coefficient signal to a time domain, frequency-component suppressing filter that is configured to receive the LMS-filtered signal as an input and to produce an echo suppressed output, responsive to the time domain filter coefficient signal.

An apparatus for suppressing residual echo signals from a time domain error signal provided by a least-mean-squared frequency domain filter, the apparatus comprising:

• a frequency domain divider, configured to divide a frequency domain representation of a reference signal, by a frequency domain representation of the error signal, the frequency domain divider being additionally configured to provide a frequency domain ratio signal;
• a converter configure to convert a frequency domain signal to a time domain signal, the converter being coupled to the frequency domain divider and additionally configured to produce as an output, a time domain, filter coefficient filter signal;
• and
• a time domain filter having a first input configured to receive the error signal, a second input configured to receive the filter coefficient signal from the converter and having an output, the time domain filter configured to suppress frequency components of the reference signal that are in the error signal.