Dialog Semiconductor B.v.

Dialog Semiconductor Gmbh

Michiel Andre Helsloot

Wessel Harm Lubberhuizen

Gavin Radolan

Paul Shields

Georgios Flamis

Lee Bathgate

Christopher Piggin

A method and system for improving echo suppression and/or duplexity of handsfree telephone applications is presented. An echo suppression unit for an electronic device comprising a loudspeaker and a microphone is described. The microphone is configured to capture a transmit signal, wherein the transmit signal comprises an echo of a receive signal rendered by the loudspeaker. The echo suppression unit is configured to determine, based on the receive signal, whether the receive signal comprises a first frequency component causing the echo of the receive signal to comprise a distortion component. The distortion component comprises one or more frequencies which are not comprised within the first frequency component. Furthermore, the echo suppression unit is configured to apply a post-filter to the transmit signal, if it is determined that the receive signal comprises the first frequency component. The post-filter is configured to selectively attenuate the distortion component.

Post-filter for handling resonance-induced echo components

An amplifier circuit and a method of amplification using automatic gain control (AGC) are disclosed. A method for reducing distortions incurred by an audio signal when being rendered by an electronic device is described. The method comprises receiving an input signal; determining signal strength; determining a frequency-dependent AGC filter; wherein the frequency-dependent AGC filter is adapted to selectively attenuate the input signal within a number N of predetermined frequency ranges, according to corresponding N degrees of attenuation; wherein N predetermined frequency ranges depend upon a rendering characteristic of the electronic device; and wherein the N-degrees of attenuation depend upon the signal strength; and attenuating the input signal using the frequency-dependent AGC filter to obtain an output signal for rendering by the electronic device.

AGC circuit for an echo cancelling circuit

A method of attenuating an input signal to obtain an output signal is described. The method comprises receiving the input signal, attenuating the input signal with a gain factor to obtain the output signal, applying a filter having a frequency response with a frequency-dependent filter gain to at least one of a copy of the input signal and a copy of the output signal to obtain a filtered signal, the frequency-dependent filter gain being arranged to emphasize frequencies within a number N of predetermined frequency ranges, N&#x3e;1; wherein the filter comprises a sequence of N sub-filters, each one of the N sub-filters having a frequency response adapted to emphasize frequencies within a corresponding one of the N predetermined frequency ranges; determining a signal strength of the filtered signal, and determining the gain factor from at least the signal strength.

Automatic gain control circuit and method for automatic gain control

A method and system for improving a perceived duplexity of handsfree telephone applications is disclosed. An echo suppression circuit for a device comprising loudspeaker and microphone is described. A circuit attenuates a subband of a transmit signal, wherein the transmit signal is captured by the microphone and wherein the transmit signal comprises an echo of a far-end signal rendered by the loudspeaker and a near-end signal. The attenuation circuit further determines a subband far-end indicator of a voice activity in the far-end signal; determines a subband near-end indicator of a voice activity of the near-end signal; determines a subband masking weight; determines a subband attenuation for the transmit signal in the subband; and attenuates the subband of the transmit signal using the determined subband attenuation.

Subband domain echo masking for improved duplexity of spectral domain echo suppressors

The present document discloses a method and system for improving echo cancellation in the presence of non-linear distortions. A circuit attenuates a transmit signal in one or more spectral bands based on a receive signal. The distorted echo comprised within the transmit signal results from distortions incurred by the receive signal when being rendered by an electronic device. The circuit compares energy values of the receive signal in multiple spectral bands with multiple corresponding spectral band dependent distortion thresholds and determines that for a first spectral band from multiple spectral bands. A first energy value from multiple energy values exceeding a first distortion threshold from multiple distortion thresholds attenuates the transmit signal in one or more spectral bands at higher frequencies than the first spectral band with corresponding spectral band dependent attenuation factors.

Growing community of inventors

Hertogenbosch, Netherlands

Michiel Andre Helsloot