Abstract: A method may include controlling switching behavior of switches of a switch-mode power supply based on a desired physical quantity associated with the switch-mode power supply, wherein the desired physical quantity is based at least in part on a slope compensation signal and generating the slope compensation signal to have a compensation value of approximately zero at an end of a duty cycle of operation of the switch-mode power supply.

Abstract: This application relates to sensing circuits for sensing a physical property or quantity of interest. The sensing circuit has an oscillator comprising a hysteretic comparator and a loop filter configured to output an oscillation signal. The loop filter comprises a first component with an electrical property that varies with the physical property or quantity of interest. A time constant of the loop filter depends on the electrical property of the first component. A decoder is configured to receive the oscillation signal and provide an indication of any change in frequency of the oscillation signal as an indication of a change in the physical property or quantity of interest. The electrical property may be an impedance, such as a resistance.

Abstract: A method of speaker verification comprises: comparing a test input against a model of a user's speech obtained during a process of enrolling the user; obtaining a first score from comparing the test input against the model of the user's speech; comparing the test input against a first plurality of models of speech obtained from a first plurality of other speakers respectively; obtaining a plurality of cohort scores from comparing the test input against the plurality of models of speech obtained from a plurality of other speakers; obtaining statistics describing the plurality of cohort scores; modifying said statistics to obtain adjusted statistics; normalising the first score using the adjusted statistics to obtain a normalised score; and using the normalised score for speaker verification.

Abstract: A method of equalising sound in a headset comprising an internal microphone configured to generate a first audio signal, an external microphone configured to generate a second audio signal, a speaker, and one or more processors coupled between the speaker, the external microphone, and the internal microphone, the method comprising: while the headset is worn by a user: determining a first audio transfer function between the first audio signal and the second audio signal in the presence of sound at the external microphone; and determining a second audio transfer function between a speaker input signal and the first audio signal with the speaker being driven by the speaker input signal; determining an electrical transfer function of the one or more processors; determining a closed-ear transfer function based on the first audio transfer function, the second audio transfer function and the electrical transfer function; and equalising the first audio signal based on a comparison between the closed-ear transfer func

Abstract: Detecting liveness of a speaker comprises: generating an ultrasound signal; receiving an audio signal comprising a reflection of the ultrasound signal; using the received audio signal comprising the reflection of the ultrasound signal to detect the liveness of a speaker; monitoring ambient ultrasound noise; and adjusting the operation of a system receiving the audio signal, based on a level of the reflected ultrasound and the monitored ambient ultrasound noise. The method can be used in a voice biometrics system, in which case detecting the liveness of a speaker comprises determining whether a received speech signal may be a product of a replay attack. The operation of the voice biometrics system may be adjusted based on a level of the reflected ultrasound and the monitored ambient ultrasound noise.

Abstract: This application relates to microphone authentication apparatus for verifying whether or not an audio signal originated at a microphone (101, 102). The microphone authentication apparatus (300) has a comparison block (301) configured to receive a first signal (A*) indicative of one or more spectral parameters of at least part of an audio signal to be verified, and compare the one or more spectral parameters to one or more predetermined characteristic microphone parameters relating to a characteristic resonance associated with an acoustic port of a microphone. The first signal (A*) may be an audio signal (A) and the microphone authentication apparatus may have a feature extract module (303) for determining the spectral parameters. Based on the comparison determination block (304) may whether the audio signal originated from a microphone and may send a verification signal (VMIC) to a voice biometric module 111.

Abstract: Detecting a replay attack on a voice biometrics system comprises: receiving a speech signal; generating an ultrasound signal; detecting a reflection of the generated ultrasound signal; detecting Doppler shifts in the reflection of the generated ultrasound signal; and identifying whether the received speech signal is indicative of the liveness of a speaker based on the detected Doppler shifts. Identifying whether the received speech signal is indicative of liveness based on the detected Doppler shifts comprises determining whether the detected Doppler shifts correspond to a speech articulation rate.

Abstract: There is described a two-terminal multi-level memristor element synthesised from binary memristors, which is configured to implement a variable resistance based on unary or binary code words. There is further described a circuit such as a synapse circuit implemented using a multi-level memristor element.

Abstract: A method may include receiving a user trigger signal indicating a user desire to update characteristics of an adaptive filter, receiving an error microphone signal indicative of the output of the transducer and the ambient audio sounds at the transducer, wherein the transducer reproduces both a source audio signal for playback to a listener and an anti-noise signal for countering the effects of ambient audio sounds in an acoustic output of the transducer, implementing the adaptive filter having a response that generates the anti-noise signal to reduce the presence of the ambient audio sounds in the error microphone signal, determining an acoustic coupling of the transducer to an error microphone for producing the error microphone signal, and responsive to a change in the acoustic coupling, prompting a user to assert the user trigger signal to indicate user desire to update characteristics of the adaptive filter.

Abstract: A system may include a tactile actuator for providing tactile feedback and a resonant phase sensing system. The resonant phase sensing system may include a resistive-inductive-capacitive sensor and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and the tactile actuator. The resistive-inductive-capacitive sensor may be configured to measure phase information associated with the resistive-inductive-capacitive sensor, based on the phase information, detect an indication of human interaction with the system proximate to the resistive-inductive-capacitive sensor, and trigger the tactile actuator to generate tactile feedback responsive to detecting the indication of human interaction.

Abstract: A method of determining whether a sound has been generated by a loudspeaker comprises receiving an audio signal representing at least a part of the sound. The audio signal is separated into different frequency bands. The signal content of different frequency bands are compared. Based on said comparison, frequency-based variations in signal content indicative of use of a loudspeaker are identified.

Abstract: A system has an output and receives an input signal. An operational amplifier has an input, an output and an offset at the input. A switched capacitor network samples the input signal at a switched capacitor frequency. An autozeroing capacitor connected to the input of the operational amplifier captures the offset during an offset capture interval according to an autozeroing frequency. Chopping and autozeroing switches, connected between the autozeroing capacitor and the switched capacitor network, chop the sampled input signal according to a chopping frequency and autozero the captured offset according to the autozeroing frequency. De-chopping switches, connected between the output of the operational amplifier and the output of the system, operate on the output of the operational amplifier at the chopping frequency to chop the autozeroed captured offset and de-chop the chopped sampled input signal processed by the operational amplifier.

Abstract: Embodiments of the disclosure relate to methods, apparatus and systems for biometric processes. The invention relates to initiating generation of an acoustic stimulus for application to a user's ear and extracting features for use in a biometric process from a measured response signal. The measured response signal may be used to derive one or more quality metrics and the quality metrics may be used to validate features extracted from the measured response. The quality metrics may be used to provide feedback to the user seeking to carry out the biometric process.

Abstract: An apparatus measures a junction temperature in an IC through a pin of the IC and concurrently provides a digital input signal to digital logic of the IC through the pin. The IC has an ESD diode structure connected to the pin. High and low side voltage sensors sense a voltage drop across the diode structure. An input multiplexer controlled by the digital input signal selectively connects high and low side current sources to the pin to concurrently provide the digital input signal to the digital logic and to drive a constant current through the diode structure. An output multiplexer controlled by the digital input signal selectively connects the high and low side voltage sensors to an output that provides a sense signal indicative of the IC junction temperature.

Abstract: This application relates to transfer of digital audio data between a host device and an accessory apparatus that may be connected to the host device via a suitable connector, such as a USB connector. A path selector is operable to establish either a first digital data path or a second digital data path for transfer of digital data. The first digital data path includes a first data bus host and a general purpose digital data interface suitable for bulk data transfer between the first data bus host and the applications processor of the device. This may be a default USB path. The second digital data path includes a second data bus host and at least one pair of second path data interfaces. The second data bus host does not form part of the applications processor and each of said second path data interfaces comprises a digital audio interface suitable for streaming of audio data.

Abstract: A method of speaker recognition comprises: receiving an audio signal comprising speech; performing a biometric process on a first part of the audio signal, wherein the first part of the audio signal extends over a first time period; obtaining a speaker recognition score from the biometric process for the first part of the audio signal; performing a biometric process on a plurality of second parts of the audio signal, wherein the second parts of the audio signal are successive sections of the first part of the audio signal, and wherein each second part of the audio signal extends over a second time period and the second time period is shorter than the first time period; obtaining a respective speaker recognition score from the biometric process for each second part of the audio signal; and determining whether there has been a speaker change based on the respective speaker recognition scores for successive second parts of the audio signal.

Abstract: A method may include generating an electrical drive waveform associated with a target actuator by stretching or compressing a reference drive waveform associated with a reference actuator in a time domain of the reference drive waveform in accordance with a time adjustment factor, wherein the time adjustment factor is determined based on a difference between a resonant frequency of the target actuator and a resonant frequency of the reference actuator. The same or another method may include generating an electrical drive waveform associated with a target actuator by increasing or decreasing an amplitude of a reference drive waveform associated with a reference actuator in accordance with an amplitude adjustment factor, wherein the amplitude adjustment factor is determined based on a difference between a resonant frequency of the target actuator and a resonant frequency of the reference actuator.

Abstract: This application relates to methods and apparatus for audio signal processing, for example by a codec. An audio signal processing module has at least one input for receiving first and second input signals and an output path for outputting an output audio signal. The first and second input signals may be supplied by a first audio component and may correspond to the same source audio data. A controller is configured to compare the first and second input signals and to select one of the first or second input signals as the basis for a signal to be supplied to said output path based on the comparison. The controller may determine a measure of similarity in content between the first and second input signals.

Abstract: A device, comprising: a pair of force sensors located for detecting a user squeeze input; and a controller operable in a squeeze detection operation to detect the user squeeze input based on a cross-correlation between respective sensor signals originating from the pair of force sensors.

Abstract: Detecting a replay attack on a voice biometrics system comprises: receiving a speech signal; generating an ultrasound signal; detecting a reflection of the generated ultrasound signal; detecting Doppler shifts in the reflection of the generated ultrasound signal; and identifying whether the received speech signal is indicative of the liveness of a speaker based on the detected Doppler shifts. Identifying whether the received speech signal is indicative of liveness based on the detected Doppler shifts comprises determining whether the detected Doppler shifts correspond to a speech articulation rate.