Knowles Electronics, Inc.

Paul Fielding Smith

Peter V Loeppert

Sarmad Qutub

John Nielsen

Anders Svava Mortensen

Aziz Yurttas

Michael Pate

Wei-Wen Dai

Shawn Beus

A microphone that includes a calibration signal generator that generates a calibration signal based upon a received invocation input. The calibration signal has known audio properties. The microphone also includes a transducer that converts sound energy into an electrical signal. An integrated circuit receives the electrical signal from the transducer. An external microphone interface provides the calibration signal to a device external to the microphone.

Audio calibration using a microphone

A driver, includes a driver block, a controller block, and a comparison block. The driver block includes an adjustable current source configured to produce a digital output stream. The controller block is coupled to the driver block. The comparison block is coupled to the driver block and the controller block. The comparison block is configured to compare the digital output stream to a reference value at a time delayed with respect to a master clock and based upon the comparison cause the controller block to adjust a strength of the driver block.

Slew rate control apparatus for digital microphones

An interface is provided between a transducer and audio processing circuitry. The interface has a switching device coupled to the transducer. The interface also has a first signal path that is selectively coupled to transducer via the switching device and includes a first output, the first signal path being configured to selectively receive input signals from the transducer, and form a first output signal at the first output by amplifying the input signals to provide a first gain. The first output is coupled to the audio processing circuitry. A second signal path is provided that is selectively coupled to the transducer via the switching device and includes a second output. The second gain is selected to be substantially larger than the first gain. The switching device is configured to switch the input signal between the first signal path and the second signal path.

Microphone interface and method of operation

Growing community of inventors

Barlett, IL, United States of America

Paul Fielding Smith