An audio host device has an electrical interface having a speaker contact, a microphone contact, and a reference contact. The reference contact is shared by a microphone and a speaker. The reference contact is also directly coupled to a power return plane of the audio host device. A difference amplifier...http://www.google.fr/patents/US8150058?utm_source=gb-gplus-shareBrevet US8150058 - Mode switching noise cancellation for microphone-speaker combinations used in two way audio communications
Mode switching noise cancellation for microphone-speaker combinations used ...
