Abstract:
An active noise control (ANC) processor has an adaptive filter that uses a reference signal to produce an anti-noise signal, and an error signal to evaluate cancellation performance. An adaptive filter algorithm engine configures the filter coefficients of the adaptive filter, in accordance with pre-shaped versions of the error and reference signals. The pre-shaping filter has a high-pass transfer function and enables the adaptive algorithm engine to increase noise cancellation performance in a high frequency band during the presence of focused or narrow-band noise energy in a low frequency band. Other embodiments are also described and claimed.
Abstract:
An active noise control (ANC) processor has an adaptive filter that uses a reference signal to produce an anti-noise signal, and an error signal to evaluate cancellation performance. An adaptive filter algorithm engine configures the filter coefficients of the adaptive filter, in accordance with pre-shaped versions of the error and reference signals. The pre-shaping filter has a high-pass transfer function and enables the adaptive algorithm engine to increase noise cancellation performance in a high frequency band during the presence of focused or narrow-band noise energy in a low frequency band. Other embodiments are also described and claimed.
Abstract:
A feed forward active noise cancellation (ANC) system for use in a portable audio device has an adaptive digital filter and a reference microphone. A non-adaptive pre-shaping digital filter has an input coupled to the reference microphone and is in series with, and in front of, the adaptive filter. The pre-shaping filter is minimum phase and presents at least 2 dB more gain over a low audio frequency band than over a high audio frequency band. This may help compensate for low frequency band difficulties, and may thereby extend ANC bandwidth at the low end without a worsening impact on the high end. Other embodiments are also described and claimed.
Abstract:
A method for detecting wind using a microphone and a speaker of an electronic device. The method obtains a microphone signal produced by the microphone. The method obtains a speaker input signal produced by the speaker that is emulating a microphone capturing ambient sound in an environment through the speaker. The method determines a coherence between the microphone signal and the speaker input signal and determines whether the coherence is below a coherence intensity threshold. In response to determining that the coherence is below the coherence intensity threshold, the method determines a presence of wind in the environment.
Abstract:
A method performed by an audio system that includes a headset with a left headset housing and a right headset housing. The method includes driving a speaker of the left headset housing with an audio signal, determining whether audio howl is present within the left headset housing by comparing spectral content from a first error microphone signal produced by a first error microphone of the left headset housing and spectral content from a second error microphone signal produced by a second error microphone of the right headset housing, and, in response to determining that audio howl is present, filtering the audio signal to mitigate the audio howl.
Abstract:
Method to perform thermal monitoring of an electro-mechanical actuator included in a device starts by receiving an in-field calibration temperature from a temperature sensor included in the device. The device may also receive an in-field calibration resistance from a resistance calculator included in the device. A calculated thermal coefficient of resistivity of the electro-mechanical actuator is then computed using an equation that relates the calculated thermal coefficient of resistivity to the in-field calibration temperature. The calculated thermal coefficient of resistivity changes based on the in-field calibration temperature. The equation includes parameters that are stored in the device. A temperature estimate of the electro-mechanical actuator is them computed based on the calculated thermal coefficient of resistivity. Other embodiments are also described.
Abstract:
A micro speaker having a capacitive sensor to sense a motion of a speaker diaphragm, is disclosed. More particularly, embodiments of the micro speaker include a conductive surface of a diaphragm facing conductive surfaces of several capacitive plate sections across a gap. The diaphragm may be configured to emit sound forward away from a magnet of the micro speaker, and the capacitive plate sections may be supported on the magnet behind the diaphragm. In an embodiment, the gap provides an available travel for the diaphragm, which may be only a few millimeters. A sensing circuit may sense capacitances of the conductive surfaces to limit displacement of the diaphragm to within the available travel.