Abstract: An apparatus measures a speaker impedance. A DAC converts a known digital input signal to an audio frequency first analog voltage signal. Resistors with known resistance attenuate the first analog voltage signal to generate a current. The known resistance effectively determines the current because the known resistance is high relative to the speaker impedance. The current is sourced into the speaker to generate a second analog voltage signal. The known resistance is sufficiently high to cause the second analog voltage signal to be inaudible as transduced by the speaker. An amplifier amplifies the second analog voltage signal with a known gain to generate a third analog voltage signal. An ADC converts the third analog voltage signal to a digital output signal. A processing element calculates the impedance of the speaker proportional to the digital output signal based on the known digital input signal, the known resistance, and the known gain.

Abstract: A primary device arranged to communicate with one or more secondary devices across a communications network. The primary device comprises at least one processor and memory comprising computer executable instructions, which when executed by the at least one processor, are configured to: receive an audio signal comprising a voice command associated with a user; determine a secondary device associated with the user from the one or more secondary devices; and transmit a response to the voice command to the determined secondary device.

Abstract: There is provided an apparatus for providing an output signal to an audio transducer, comprising: a first signal path for receiving a first digital audio input signal, applying a first digital gain, and outputting an amplified first digital audio input signal; a second signal path, for receiving a second digital audio input signal, applying a second digital gain, and outputting an amplified second digital audio input signal; converter circuitry, coupled to the first and second signal paths, for converting at least the amplified first and second digital audio input signals into the analogue domain, and outputting an analogue audio input signal; and an analogue gain element, for applying an analogue gain to the analogue audio input signal and outputting the output signal.

Abstract: A method of speaker identification comprises receiving a speech signal and dividing the speech signal into segments. Following each segment, a plurality of features are extracted from a most recently received segment, and scoring information is derived from the extracted features of the most recently received segment. The scoring information derived from the extracted features of the most recently received segment is combined with previously stored scoring information derived from the extracted features of any previously received segment. The new combined scoring information is stored, and an identification score is calculated using the combined scoring information.

Abstract: The present disclosure relates to a fluency aid comprising: a pacing signal generator operable to output a signal for generating, at regular time intervals, an audible sound; and a controller operable, in response to a voice being detected by a voice detector, to control the pacing signal generator such that the output signal causes the audible sound to continue, stop or fade.

Abstract: A method for mechanically driving a display screen to produce acoustic sound may include mechanically driving a first mechanical transducer mechanically coupled to the display screen to generate acoustic sound from the display screen and controlling a second mechanical transducer mechanically coupled to the display screen at a specific location to apply an acoustic null to the specific location in order to localize generation of the acoustic sound from the display screen.

Abstract: A method of determining a phase misalignment between a first signal generated from a first signal path and a second signal generated from a second signal path may include obtaining multiple samples of the first signal proximate to when the first signal crosses zero wherein the first signal can be approximated as linear; obtaining multiple samples of the second signal proximate to when the second signal crosses zero wherein the first signal can be approximated as linear; based on the multiple samples of the first signal, approximating a first time at which the first signal crosses zero; based on the multiple samples of the second signal, approximating a second time at which the second signal crosses zero; and determining the phase misalignment between the first signal and the second signal based on a difference between the first time and the second time.

Abstract: A system may include a current digital-to-analog converter (IDAC) configured to convert a digital input signal into an output current signal and a switched-mode power supply configured to provide electrical energy in the form of a supply voltage to the IDAC for operation of the IDAC, the switched-mode power supply configured to track a voltage signal derived from the digital input current signal and generate the supply voltage based on the voltage signal and a voltage headroom above the voltage signal.

Abstract: An encoding for data in an audio data stream may be indicated in the data stream using a footer stored in low-order bits of data frames in the audio data stream. When the audio data stream may include either Pulse Code Modulation (PCM) or Direct Stream Digital (DSD) data, PCM data may be marked with a footer to indicate the encoding as PCM. The footer may be a fixed value, an alternating fixed value, a predetermined sequence of values, or a value computed based on the PCM data. Examples of computed values for the footer marker may include an error code, an error correction code (ECC), and a scrambled code.

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 bipolar output charge pump circuit having a network of switching paths for selectively connecting an input node and a reference node for connection to an input voltage, a first pair of output nodes and a second pair of output nodes, and two pairs of flying capacitor nodes, and a controller for controlling the switching of the network of switching paths. The controller is operable to control the network of switching paths when in use with two flying capacitors connected to the two pairs of flying capacitor nodes, to provide a first bipolar output voltage at the first pair of output nodes and a second bipolar output voltage at the second pair of bipolar output nodes.

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: Embodiments of the invention relate to methods, apparatus and systems for biometric processes. The methods include updating stored ear model data for a user following successful authentication of the user. The ear model data may be acquired using a personal audio device that generates an acoustic stimulus and detects a measured response. The acquisition of the ear model data may be responsive to a determination that the personal audio device is inserted into or placed adjacent to the user's ear. The acquisition of the ear model data may also be responsive to the determination that the personal audio device has not been removed from or moved away from the user's ear.

Abstract: A differential output current digital-to-analog (IDAC) circuit may include a delta-sigma modulator configured to receive a digital input signal, a control circuit responsive to the delta-sigma modulator configured to perform a DAC decode operation, a plurality of DAC elements responsive to the DAC decode operation, the plurality of DAC elements configured to, in concert, generate a differential output current signal based on the digital input signal to a load coupled to a pair of output terminals of the IDAC, and a plurality of warming switches, each warming switch coupled to a respective bias transistor of a respective DAC element of the plurality of DAC elements, wherein the control circuit may further be configured to selectively control each such warming switch in order to selectively de-bias and bias a respective bias transistor of such warming switch when a respective DAC element of the respective bias transistor is output-disabled from generating the differential output current signal.

Abstract: Detecting a replay attack on a voice biometrics system comprises receiving a speech signal; forming an autocorrelation of at least a part of the speech signal; and identifying that the received speech signal may result from a replay attack based on said autocorrelation. Identifying that the received speech signal may result from a replay attack may be achieved by: comparing the autocorrelation with a reference value; and identifying that the received speech signal may result from a replay attack based on a result of the comparison of the autocorrelation with the reference value, or by: supplying the autocorrelation to a neural network trained to distinguish autocorrelations formed from speech signals resulting from replay attacks from autocorrelations formed from speech signals not resulting from replay attacks.

Abstract: Embodiments described herein provide methods and apparatus for outputting a haptic signal to a haptic transducer. A method comprises storing a representation of a part of the haptic signal comprising a first information point indicating a first amplitude and at least one first frequency of the part of the haptic signal at a first time, wherein the representation is associated with a user experience; responsive to receiving an indication of occurrence of the user experience, determining the haptic signal based on the first information point such that the part of the haptic signal has the first amplitude and the at least one first frequency at the first time. The method may further comprise outputting the haptic signal to the haptic transducer.

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 for measuring a capacitive sensor output may include applying an excitation signal to a capacitor of the capacitive sensor which causes generation of a modulated signal from a baseband signal, wherein the excitation signal is of a carrier frequency which is higher than frequency content of the baseband signal, demodulating the modulated signal to generate an intermediate signal representative of a capacitance of the capacitor wherein the demodulating is based, at least in part, on the excitation signal, converting the intermediate signal into a pulse-density modulated output signal with a pulse-density modulator, and shaping a noise transfer function of the pulse-density modulator to have an approximate zero at the carrier frequency.

Abstract: According to one or more examples of the present disclosure there is provided a fluency aid comprising: an altered auditory feedback, AAF, generator operable to receive an input signal derived from speech of a user and to apply a predefined variation to the input signal in order to generate a feedback signal for providing altered auditory feedback to the user, wherein the AAF generator is further operable to automatically change a property of the variation that is applied to the input signal.

Abstract: A signal amplifying circuit and associated methods and apparatuses, the circuit comprising: a signal path extending from an input terminal to an output terminal, a gain controller arranged to control the gain applied along the signal path in response to a control signal; an output stage within the signal path for generating the output signal, the output stage having a gain that is substantially independent of its supply voltage, and a variable voltage power supply comprising a charge pump for providing positive and negative output voltages, the charge pump comprising a network of switches that is operable in a number of different states and a controller for operating the switches in a sequence of the states so as to generate positive and negative output voltages together spanning a voltage approximately equal to the input voltage.