Low complexity echo compensation system

US8194852B2 · kind B2 · utility

Assignee

• Nuance Communications, Inc. · US

Inventors

• Markus Buck · Biberach, DE
• Tim Haulick · Blaubeuren, DE
• Martin Rossler · Ulm, DE
• Gerhard Uwe Schmidt · Ulm, DE
• Walter Schnug · Memmingen, DE

Key dates

• Filing date: Dec 13, 2007
• Grant date: Jun 5, 2012
• Expiry date: Feb 2, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04M9/082
• WIPO field: Telecommunications
• WIPO sector: Electrical engineering

Abstract

An echo reduction system includes a signal analysis filter that converts an input into sub-band signals. A signal down-sampling circuit down-samples the sub-band signals at a first down-sampling rate. An echo analysis filter converts a loudspeaker signal into echo sub-band signal that are further processed by an echo down-sampling circuit. The circuit down-samples the echo sub-band signals at a second down-sampling rate to generate down-sampled echo sub-band signals. An echo compensation filter folds the down-sampled echo sub-band signals with an estimated impulse response of a loudspeaker-room-input system. A second echo down-sampling circuit down-samples the folded down-sampled echo sub-band signals at a third down-sampling rate to generate estimated echo sub-band signals. The first down-sampling rate is equal to the product of the second and third down-sampling rates.