Abstract: This application describes methods and apparatus for speaker recognition. An apparatus according to an embodiment has an analyzer for analyzing each frame of a sequence of frames of audio data which correspond to speech sounds uttered by a user to determine at least one characteristic of the speech sound of that frame. An assessment module determines, for each frame of audio data, a contribution indicator of the extent to which that frame of audio data should be used for speaker recognition processing based on the determined characteristic of the speech sound. Said contribution indicator comprises a weighting to be applied to each frame in the speaker recognition processing. In this way frames which correspond to speech sounds that are of most use for speaker discrimination may be emphasized and/or frames which correspond to speech sounds that are of least use for speaker discrimination may be de-emphasized.

Abstract: This application describes methods and apparatus for generating a prompt to be presented to a user for the user to vocalise as part of speaker recognition. An apparatus according to an embodiment has a selector for selecting at least one vocal prompt element to form at least part of said prompt from a predetermined set of a plurality of vocal prompt elements. The selector is configured to select the vocal prompt element based, at least partly, on an indication of the operating conditions for the biometric speaker recognition, for example background noise. The prompt is selected to be one which will provide a good likelihood of discrimination between users when vocalised and used for speaker recognition in the current operating conditions. The prompt may be issued as part of a verification process for an existing user or an enrolment process for an enrolling user.

Abstract: This application describes methods and apparatus for speaker recognition. An apparatus according to an embodiment has an analyzer (202) for analyzing each frame of a sequence of frames of audio data (AIN) which correspond to speech sounds uttered by a user to determine at least one characteristic of the speech sound of that frame. An assessment module (203) determines, for each frame of audio data, a contribution indicator of the extent to which the frame of audio data should be used for speaker recognition processing based on the determined characteristic of the speech sound. In this way frames which correspond to speech sounds that are of most use for speaker discrimination may be emphasized and/or frames which correspond to speech sounds that are of least use for speaker discrimination may be de-emphasized.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to down-convert signals in the second signal path from the second frequency band to a lower frequency band.

Abstract: This application describes methods and apparatus for speaker recognition. An apparatus according to an embodiment has an analyzer for analyzing each frame of a sequence of frames of audio data which correspond to speech sounds uttered by a user to determine at least one characteristic of the speech sound of that frame. An assessment module determines, for each frame of audio data, a contribution indicator of the extent to which that frame of audio data should be used for speaker recognition processing based on the determined characteristic of the speech sound. Said contribution indicator comprises a weighting to be applied to each frame in the speaker recognition processing. In this way frames which correspond to speech sounds that are of most use for speaker discrimination may be emphasized and/or frames which correspond to speech sounds that are of least use for speaker discrimination may be de-emphasized.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to down-convert signals in the second signal path from the second frequency band to a lower frequency band.

Abstract: A microphone unit has a transducer, for generating an electrical audio signal from a received acoustic signal; a speech coder, for obtaining compressed speech data from the audio signal; and a digital output, for supplying digital signals representing said compressed speech data. The speech coder may be a lossy speech coder, and may contain a bank of filters with centre frequencies that are non-uniformly spaced, for example mel frequencies.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to apply a selective gain modulation to signals in the second signal path.

Abstract: A microphone unit has a transducer, for generating an electrical audio signal from a received acoustic signal; a speech coder, for obtaining compressed speech data from the audio signal; and a digital output, for supplying digital signals representing said compressed speech data. The speech coder may be a lossy speech coder, and may contain a bank of filters with center frequencies that are non-uniformly spaced, for example mel frequencies.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to down-convert signals in the second signal path from the second frequency band to a lower frequency band.

Abstract: This application describes methods and apparatus for generating a prompt to be presented to a user for the user to vocalise as part of speaker recognition. An apparatus according to an embodiment has a selector for selecting at least one vocal prompt element to form at least part of said prompt from a predetermined set of a plurality of vocal prompt elements. The selector is configured to select the vocal prompt element based, at least partly, on an indication of the operating conditions for the biometric speaker recognition, for example background noise. The prompt is selected to be one which will provide a good likelihood of discrimination between users when vocalised and used for speaker recognition in the current operating conditions. The prompt may be issued as part of a verification process for an existing user or an enrolment process for an enrolling user.

Abstract: This application describes methods and apparatus for speaker recognition. An apparatus according to an embodiment has an analyzer (202) for analyzing each frame of a sequence of frames of audio data (AIN) which correspond to speech sounds uttered by a user to determine at least one characteristic of the speech sound of that frame. An assessment module (203) determines, for each frame of audio data, a contribution indicator of the extent to which the frame of audio data should be used for speaker recognition processing based on the determined characteristic of the speech sound. In this way frames which correspond to speech sounds that are of most use for speaker discrimination may be emphasized and/or frames which correspond to speech sounds that are of least use for speaker discrimination may be de-emphasized.

Abstract: A microphone unit has a transducer, for generating an electrical audio signal from a received acoustic signal; a speech coder, for obtaining compressed speech data from the audio signal; and a digital output, for supplying digital signals representing said compressed speech data. The speech coder may be a lossy speech coder, and may contain a bank of filters with centre frequencies that are non-uniformly spaced, for example mel frequencies.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to down-convert signals in the second signal path from the second frequency band to a lower frequency band.

Abstract: This application relates to methods and apparatus for digital microphones. Disclosed is a digital microphone apparatus (300) for outputting a digital output signal (DATA) at a sample rate defined by a received clock signal (CLK). The apparatus includes a band splitter (302) configured to receive a microphone signal (SMD) indicative of an output of a microphone transducer and split said microphone signal into first signal path (SP1) for frequencies in a first band and a second signal path (SP2) for frequencies in a second band, the frequencies of the second band being higher than the frequencies in the first band. A modulation block (304) is configured to operate on the second signal path to apply a selective gain modulation to signals in the second signal path.

Abstract: Systems and methods of estimating a motor position of a motor are disclosed. One exemplary system and method involve observing motor currents of the motor at two different times. Average motor voltages of the motor are determined between the two different times. Average back electro motive force (BEMF) values of the motor are calculated between the two different times. The BEMF values are in conformity with the observed motor currents and the average motor voltages. Another exemplary system and method for estimating a rotor position of a motor involve a motor position estimator that receives information from the motor and estimates a rotor position for a future time.

Abstract: A system and method of controlling a motor are disclosed. The system comprises a current observer for observing a motor current at a sampling rate and a proportionate-integral controller that provides a proportionate path and an integral path and at least forms part of a proportionate-integral control loop based on the motor current. The current observer observes a motor current of the motor at a sampling rate. The proportionate path calculates, for a present cycle of the sampling rate, a proportionate path term for the proportionate-integral control loop based on the motor current. The system outputs a respective motor output voltage to the motor in conformity with the proportionate path term calculated for the present cycle. In conformity with the motor current, the integral path calculates an integral path term for another respective motor output voltage to be used in a later cycle of the sampling rate.

Abstract: A light emitting diode (LED) lighting system includes a switching power converter having an input for coupling to an alternating current (AC) power source, an output, and a switch. The LED lighting system also includes an LED lighting subsystem coupled to receive power from the output of the switching power converter. The LED lighting subsystem includes a current source for one or more LEDs, and the current source has a control node and a sense node. The LED lighting system additionally includes a switch state controller coupled to the switching power converter and coupled to the LED lighting subsystem. The switch state controller controls switching of the switch and varies a control current provided to the control node of the current source based on at least a parameter sensed from the sense node.

Abstract: A system and method of controlling a motor are disclosed. The system comprises a current observer for observing a motor current at a sampling rate and a proportionate-integral controller that provides a proportionate path and an integral path and at least forms part of a proportionate-integral control loop based on the motor current. The current observer observes a motor current of the motor at a sampling rate. The proportionate path calculates, for a present cycle of the sampling rate, a proportionate path term for the proportionate-integral control loop based on the motor current. The system outputs a respective motor output voltage to the motor in conformity with the proportionate path term calculated for the present cycle. In conformity with the motor current, the integral path calculates an integral path term for another respective motor output voltage to be used in a later cycle of the sampling rate.

Abstract: Systems and methods of estimating a motor position of a motor are disclosed. One exemplary system and method involve observing motor currents of the motor at two different times. Average motor voltages of the motor are determined between the two different times. Average back electro motive force (BEMF) values of the motor are calculated between the two different times. The BEMF values are in conformity with the observed motor currents and the average motor voltages. Another exemplary system and method for estimating a rotor position of a motor involve a motor position estimator that receives information from the motor and estimates a rotor position for a future time.