DIGITAL DUAL MICROPHONE MODULE WITH CROSS FAD

摘要

A method of operating a microphone system includes providing first and second microphones associated with a same human speaker. An analog ambient noise signal is received from the first microphone. An analog speech signal is received from the second microphone. The analog ambient noise signal is converted into a digital ambient noise signal. The analog speech signal is converted into a digital speech signal. Digital noise cancellation is performed on the digital speech signal dependent upon the digital ambient noise signal. The digital noise cancellation is performed by digital circuitry. The noise canceled digital speech signal is inputted into an intercom system. A low power condition of the microphone system and/or a failure of the digital circuitry is sensed. In response to the sensing step, an analog-based intercom signal is inputted into the intercom system. The analog-based intercom signal is dependent on the analog speech signal and substantially independent of the analog ambient noise signal. The analog-based intercom signal is inputted into the intercom system without noise cancellation having been performed on the analog-based intercom signal.