Abstract: The present disclosure relates to circuitry for driving a piezoelectric transducer based on an input signal. The circuitry comprises: primary driver circuitry configured to receive the input signal and to output a primary driving signal to the piezoelectric transducer based on the input signal; and secondary driver circuitry configured to receive an error signal indicative of an error between the input signal and the primary driving signal and to output a secondary driving signal to the piezoelectric transducer based on the error signal, wherein the primary driver circuitry and the secondary driver circuitry both comprise switching converter circuitry.

Abstract: A method for identifying a mechanical impedance of an electromagnetic load may include generating a waveform signal for driving an electromagnetic load and, during driving of the electromagnetic load by the waveform signal or a signal derived therefrom, receiving a current signal representative of a current associated with the electromagnetic load and a back electromotive force signal representative of a back electromotive force associated with the electromagnetic load. The method may also include implementing an adaptive filter to identify parameters of the mechanical impedance of the electromagnetic load, wherein an input of a coefficient control for adapting coefficients of the adaptive filter is a first signal derived from the back electromotive force signal and a target of the coefficient control for adapting coefficients of the adaptive filter is a second signal derived from the current signal.

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: The present application relates to structures for supporting mechanical, electrical and/or electromechanical components, devices and/or systems and to methods of fabricating such structures. The application describes a primary die comprising an aperture extending through the die. The aperture is suitable for receiving a secondary die. A secondary die may be provided within the aperture of the primary die.

Abstract: A method of recording measurement data for characterizing a response of a given type of device to an applied force, the given type defining devices of that type as comprising a defined arrangement of a surface and N force sensors of the device concerned, where N?1, each force sensor configured to output a sensor signal, wherein in the defined arrangement the N force sensors are operatively coupled to a defined input region of the surface so as to sense a force applied to that input region, the method comprising: for a specimen device of the given type, performing at least one measurement procedure, each measurement procedure comprising at least one measurement operation, each measurement operation comprising applying a defined force at a corresponding location on the input region of the device concerned and recording measurement data for that device and location based on the sensor signals of the N force sensors of that device.

Abstract: A method of speaker identification comprises receiving an audio signal representing speech; performing a first voice biometric process on the audio signal to attempt to identify whether the speech is the speech of an enrolled speaker; and, if the first voice biometric process makes an initial determination that the speech is the speech of an enrolled user, performing a second voice biometric process on the audio signal to attempt to identify whether the speech is the speech of the enrolled speaker. The second voice biometric process is selected to be more discriminative than the first voice biometric process.

Abstract: A power delivery system may include a power converter configured to electrically couple to a power source and further configured to supply electrical energy to one or more loads electrically coupled to an output of the power converter and control circuitry configured to monitor a first voltage derived from the power source, wherein the first voltage is indicative of a total power demanded by the power converter, and control a limit for a current supplied from the power source to the one or more loads based on comparison of the first voltage to a threshold voltage, wherein the threshold voltage is indicative of a point within a range of operation of the power converter at which the power converter delivers a maximum amount of power to the one or more loads.

Abstract: A power converter may include an input for receiving an input signal and output for generating an intermediate signal that is a power converted signal from the input signal wherein the intermediate signal is determined based on various parameters of a signal path that utilizes the intermediate signal, wherein the various parameters comprise one or more of the following: a peak output signal of the signal path, energy requested over a period of time by the signal path, available energy from an energy source to the power converter, stored energy at an output of the power converter, and stored energy of a battery for providing electrical energy at the input.

Abstract: A controller for use in a device which comprises at least two force sensors in a given arrangement, the controller operable, based on input sensor signals derived from the force sensors, to carry out an arrangement-related operation in which an output sensor signal is generated based on at least two said input sensor signals and the arrangement of the force sensors in the device so that the output sensor signal is dependent on said arrangement.

Abstract: A method of authenticating a speech signal in a first device comprises receiving a speech signal, and performing a live speech detection process to determine whether the received signal represents live speech. The live speech detection process generates a live speech detection output. A certificate is formed by encrypting at least the live speech detection output. The received signal, and the certificate, are transmitted to a separate second device.

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, 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 mode and a second mode when in use with two flying capacitors connected to the flying capacitor nodes, wherein at least the first mode corresponds to a bipolar output voltage of +/?3VV, +/?VV/5 or +/?VV/6.

Abstract: A power delivery system may include a power converter configured to electrically couple to a power source and further configured to supply electrical energy to one or more loads electrically coupled to an output of the power converter and control circuitry configured to control the power converter in accordance with a control variable.

Abstract: A system may include a resistive-inductive-capacitive sensor, a driver configured to drive the resistive-inductive-capacitive sensor at a driving frequency, and a measurement circuit communicatively coupled to the resistive-inductive-capacitive sensor and configured to determine a measured change in a resonant frequency of the resistive-inductive-capacitive sensor and based on the measured change, modify the driving frequency.

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 method of modelling speech of a user of a headset comprising a microphone, the method comprising: receiving a first sample, from a bone-conduction sensor, representing bone-conducted speech of the user; obtaining a measure of fundamental frequency of the bone-conducted speech in each of a plurality of speech frames of the first sample; obtaining a first distribution of the fundamental frequencies of the bone-conducted speech over the plurality of speech frames; receiving, from the microphone, a second sample; determining a first acoustic condition at the headset based on the second signal; performing a biometric process based on the first distribution of fundamental frequencies and the first acoustic condition.

Abstract: A clock generator receives first and second clock signals, and input representing a desired frequency ratio. A comparison is made between frequencies of an output clock signal and the first clock signal, and a first error signal represents the difference between the desired frequency ratio and this comparison result. The first error signal is filtered. A comparison is made between frequencies of the output clock signal and the second clock signal, and a second error signal represents the difference between the filtered first error signal and this comparison result. The second error signal is filtered. A numerically controlled oscillator receives the filtered second error signal and generates an output clock signal. As a result, the output clock signal has the jitter characteristics of the first input clock signal over a useful range of jitter frequencies and the frequency accuracy of the second input clock signal.

Abstract: Detecting a replay attack on a voice biometrics system comprises: receiving a speech signal from a voice source; generating and transmitting an ultrasound signal through a transducer of the device; detecting a reflection of the transmitted ultrasound signal; detecting Doppler shifts in the reflection of the generated ultrasound signal; and identifying whether the received speech signal is indicative of liveness of a speaker based on the detected Doppler shifts. The method further comprises: obtaining information about a position of the device; and adapting the generating and transmitting of the ultrasound signal based on the information about the position of the device.

Abstract: Circuitry for controlling current between a load and a power supply, the circuitry comprising: an output stage comprising: an input node configured to be coupled to the power supply; and an output node configured to be coupled to the load; and one or more control nodes for controlling a conduction path between the input node and the output node; and protection circuitry coupled to the one or more control nodes, the protection circuitry configured to break the conduction path between the input node and the output node when a load voltage at the output node exceeds a supply voltage at the input node, wherein the protection circuitry comprises: an active protection circuit configured to break the conduction path when the supply voltage exceeds an operational threshold of the active protection circuit; and a passive protection circuit configured to break the conduction path when the supply voltage is below an operation threshold of the active protection circuit.

Abstract: In order to detect a replay attack in a speaker recognition system, at least one feature is identified in a detected magnetic field. It is then determined whether the at least one identified feature of the detected magnetic field is indicative of playback of speech through a loudspeaker. If so, it is determined that a replay attack may have taken place.

Abstract: A method of detecting live speech comprises: receiving a signal containing speech; obtaining a first component of the received signal in a first frequency band, wherein the first frequency band includes audio frequencies; and obtaining a second component of the received signal in a second frequency band higher than the first frequency band. Then, modulation of the first component of the received signal is detected; modulation of the second component of the received signal is detected; and the modulation of the first component of the received signal and the modulation of the second component of the received signal are compared. It may then be determined that the speech may not be live speech, if the modulation of the first component of the received signal differs from the modulation of the second component of the received signal.