Abstract: A noise cancelling headset for voice communications contains a microphone at each of the user's ears and a voice microphone. The headset shares the use of the ear microphones for improving signal-to-noise ratio on both the transmit path and the receive path.

Abstract: An integrated audio transducer with associated signal processing electronics is disclosed. A silicon audio transducer, such as a MEMS microphone or speaker, can be integrated with audio processing electronics in a single package. The audio processing electronics can be configured using control signals. The audio processing electronics can provide a single line serial data interface and a single line control interface. The audio transducers can be integrated with associated processing electronics. A silicon microphone can be integrated with an Analog to Digital Converter (ADC). The ADC output can be a single line serial interface. The ADC can be configured using a single line serial control interface. A speaker may be integrated with a Digital to Analog Converter (DAC). Audio transducers can also be integrated with more complex processing electronics. Audio processing parameters such as gain, dynamic range, and filter characteristics may be configured using the serial interface.

Abstract: An audio band processor and a method and circuit for controlling its gain. The audio band processor comprises a first variable gain amplifier for receiving an analog audio signal; an analog to digital converter for converting the analog audio signal to a digital audio signal; and an interface circuit for encoding the digital audio signal. The interface circuit also arranges the digital audio signal into a sequence of encoded transmit frames, and receives a sequence of encoded receive frames, each receive frame comprising a predetermined number of encoded digital audio signal data bits and a predetermined number of digital gain control bits. The interface circuit also adjusts a gain level of the first variable gain amplifier in response to the digital gain control bits. In another embodiment, the audio band processor further comprises a second variable gain amplifier, and the interface circuit adjusts a gain level of the second variable gain amplifier in response to the digital gain control bits.