公开(公告)号：US10825440B2

公开(公告)日：2020-11-03

申请号：US16264409

申请日：2019-01-31

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Jeffrey Alderson ,  Ning Li ,  Ronald Coapstick

IPC: G10K11/178 ,  H04R1/40 ,  H04R3/00 ,  H04R29/00

Abstract: A method for calibrating an ANC-enabled portable audio device having microphones plays continuously a calibration sound by a calibrated speaker of a test station separate from the device. For each microphone of all the microphones, a microphone calibration value is computed using a comparison of a predetermined level and a measured level of an audio signal transduced by the microphone in response to the continuously-played calibration sound. The calibration is done without using a microphone of the test station. A processing element of the device may be programmed to make the comparison and computation. The processing element also causes a speaker of the device to generate a second calibration sound, measures a second level while the computed calibration value is applied to one of microphones (e.g., error microphone), and computes a calibration value for the device speaker using a comparison of a predetermined level and the second level.

公开(公告)号：US10810990B2

公开(公告)日：2020-10-20

申请号：US16261775

申请日：2019-01-30

Applicant: Cirrus Logic International Semiconductor Ltd.

Inventor： Gabriel Vogel ,  Jeffrey Alderson ,  Ryan A. Hellman ,  Nitin Kwatra

IPC: G10K11/178

Abstract: An active noise cancellation (ANC) system including a selectable decimation rate decimator that receives an oversampled digital input and has an input that selects the decimation rate, a filter that receives an output of the decimator, and a selectable interpolation rate interpolator that receives an output of the filter and has an input that selects the interpolation rate. The selectable decimation rate decimator and the selectable interpolation rate interpolator operate to provide a selectable sample rate for the filter based on the selected decimation and interpolation rates. The filter may be an anti-noise filter, feedback filter, and/or a filter that models an acoustic transfer function of the ANC system. Rate selection may be static, or dynamically controlled based on battery or ambient noise level. A ratio of the decimation rate and the interpolation rate is fixed independent of the dynamically controlled decimation and interpolation rates.