Abstract: A method for authenticating a user of an electronic device is disclosed. The method comprises: responsive to detection of a trigger event indicative of a user interaction with the electronic device, generating an audio probe signal to play through an audio transducer of the electronic device; receiving a first audio signal comprising a response of the user's ear to the audio probe signal; receiving a second audio signal comprising speech of the user; and applying an ear biometric algorithm to the first audio signal and a voice biometric algorithm to the second audio signal to authenticate the user as an authorised user.

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: This application relates to control of semiconductor devices, in particular MOS devices, so as to reduce RTS/flicker noise. A circuit (100) includes a first MOS device (103, 104) and a bias controller (107). The circuit is operable in at least a first circuit state (PRO) in which the first MOS device is active to contribute to a first signal (Sout) and a second circuit state (PRST) in which the first MOS device does not contribute to the first signal. The bias controller is operable to control voltages at one or more terminals of the first MOS device to apply a pre-bias (VRB1, VPB2) during an instance of the second circuit state. The pre-bias is applied to set an occupancy state of charge carriers traps within the first MOS device, to limit noise during subsequent operation in the first circuit state. In embodiments, the bias controller is configured so that at least one parameter of the pre-bias is selectively variable in use based on one or more operating conditions.

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: The present invention relates to methods, apparatus and systems for audio playback via a personal audio device following a biometric process. A personal audio device may be used to obtain ear model data for authenticating a user via an ear biometric authentication system. Owing to that successful authentication, the electronic device is informed of the person who is listening to audio playback from the device. Thus the device can implement one or more playback settings which are specific to that authorised user.

Abstract: This application relates an activity detector (100) for detecting signal activity in an input audio signal (SIN), such as may be used for always-on speech detection. The activity detector has a first time-encoding modulator (TEM) 101 including a first hysteretic comparator (201) for generating a PWM (pulse-width modulation) signal based on the input audio signal. A second TEM (103) having a second hysteretic comparator (401) is arranged to receive a reference voltage (VMID) and generate a clock signal (SCLK). A time-decoding converter (102) receives the clock signal and generates count values of a number of cycles of the clock signal in periods defined by the PWM signal. An activity monitor (104) is responsive to a count signal (SCT) from the TDC 102 to determine whether the input audio signal comprises signal activity above a defined threshold.

Abstract: A method for improving the robustness of a speech processing system having at least one speech processing module comprises: receiving an input sound signal comprising audio and non-audio frequencies; separating the input sound signal into an audio band component and a non-audio band component; and identifying possible interference within the audio band from the non-audio band component. Based on such an identification, the operation of a downstream speech processing module is adjusted.

Abstract: This application relates to time-encoding modulators (TEMs). A TEM receives an input signal (SIN) and outputs a time-encoded output signal (SOUT). A filter arrangement receives the input signal and also a feedback signal (SFB) from the TEM output, and generates a filtered signal (SFIL) based, at least in part, on the feedback signal. A comparator receives the filtered signal and outputs a time-encoded signal (SPWM) based at least in part on the filtered signal. The time encoding modulator is operable in a first mode with the filter arrangement configured as an active filter and in a second mode with the filter arrangement configured as a passive filter. The filter arrangement may include an op-amp, capacitance and switch network. In the first mode the op-amp is enabled, and coupled with the capacitance to provide the active filter. In the second mode the op-amp is disabled and the capacitance coupled to a signal path for the feedback signal to provide a passive filter.

Abstract: The present disclosure provides methods, systems, devices and computer program products for authenticating a user based on a comparison of audio signals to a stored voice model for an authorised user. In one aspect, a method comprises: obtaining a first audio signal that comprises a representation of a bone-conducted signal, wherein the bone-conducted signal is conducted via at least part of the user's skeleton; obtaining a second audio signal that comprises a representation of an air-conducted signal; and, responsive to a determination that the first audio signal comprises a voice signal, enabling updates to the stored voice model for the authorised user based on the second audio signal.

Abstract: The present disclosure relates to a computing system. The computing system comprises a data input configured to receive an input data signal, a computation unit having an input coupled with the data input, the computation unit being operative to apply a weight to a signal received at its input to generate a weighted output signal, and a controller. The controller is configured to monitor a parameter of the input signal and/or a parameter of the output signal and to issue a control signal to the computation unit to control a level of accuracy of the weighted output signal based at least in part on the monitored parameter.

Abstract: Driver circuitry is disclosed for driving an electroacoustic transducer to provide an output comprising both ultrasonic and audio signal components. The driver circuitry comprises an adjustment module configured to reduce the level of said ultrasonic component signal in response to an increase in an operational variable indicative of a level of said audio signal component, while also increasing the pulse duration, duty cycle, repetition frequency or frequency span or bandwidth of the ultrasonic component.

Abstract: This application relates to time-encoding modulators (TEMs). A TEM (100) receives an input signal (SIN) and outputs a time encoded signal (SPWM). A comparator (101) is located within a forward signal path of a feedback loop of the TEM. Also in the feedback loop are a filter (104) and a delay element (106) for applying a controlled delay. In some embodiments a latching element (101, 302; 106, 402) is located within the forward signal path to synchronise any signal transitions output from the latching element to a received first clock signal. Any signal transitions in the output (SOUT) from the modulator are thus synchronised to the first clock signal. In some embodiments the delay element (106) is a digital delay element which is synchronised to the first clock signal.

Abstract: The present disclosure relates to a neural network system comprising: a data input configured to receive an input data signal and analog neural network circuitry having an input coupled with the data input. The analog neural network circuitry is operative to apply a weight to a signal received at its input to generate a weighted output signal. The neural network system further comprises compensation circuitry configured to apply a compensating term to the input data signal to compensate for error in the analog neural network circuitry.

Abstract: A method of own voice detection is provided for a user of a device. A first signal is detected, representing air-conducted speech using a first microphone of the device. A second signal is detected, representing bone-conducted speech using a bone-conduction sensor of the device. The first signal is filtered to obtain a component of the first signal at a speech articulation rate, and the second signal is filtered to obtain a component of the second signal at the speech articulation rate. The component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate are compared, and it is determined that the speech has not been generated by the user of the device, if a difference between the component of the first signal at the speech articulation rate and the component of the second signal at the speech articulation rate exceeds a threshold value.

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: 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: In order to detect a replay attack on a voice biometrics system, a speech signal is received at at least a first microphone and a second microphone. The speech signal has components at first and second frequencies. The method of detection comprises: obtaining information about a position of a source of the first frequency component of the speech signal, relative to the first and second microphones; obtaining information about a position of a source of the second frequency component of the speech signal, relative to the first and second microphones; comparing the position of the source of the first frequency component and the position of the source of the second frequency component; and determining that the speech signal may result from a replay attack if the position of the source of the first frequency component differs from the position of the source of the second frequency component by more than a threshold amount.

Abstract: This application relates to computing circuitry (200), and in particular to analogue computing circuitry suitable for neuromorphic computing. An analogue computation unit (210) for processing data is supplied with a first voltage (VCOMP) from a voltage regulator (220) which is operable in a sequence of phases to cyclically regulate the first voltage. A controller (230) is configured to control operation of the voltage regulator and/or the analogue computation unit, such that the analogue computation unit processes data during a plurality of compute periods that avoid times at which the voltage regulator undergoes a phase transition which is one of a predefined set of phase transitions between defined phases in said sequence of phases. This avoids performing computation operations during a phase transition of the voltage regulator that could result in a transient or disturbance in the first voltage, which could adversely affect the computing.

Abstract: A method of detecting a replay attack on a voice biometrics system comprises: receiving an audio signal representing speech; detecting a magnetic field; determining if there is a correlation between the audio signal and the magnetic field; and if there is a correlation between the audio signal and the magnetic field, determining that the audio signal may result from a replay attack.

Abstract: This application relates to computing circuitry (200), in particular for analogue computing circuitry suitable for neuromorphic computing. The circuitry (200) has a plurality of memory cells (201), each memory cell having an input electrode (201) for receiving a cell input signal and an output (203P, 203N) for outputting a cell output signal (IP, IN), with first and second paths connecting the input electrode to the output. The cell output signal thus depends on a differential current between the first and second paths due to the cell input signal. Each memory cell also comprises at least one programmable-resistance memory element (204) in each of the first and second paths and is controllable, by selective programming of the programmable-resistance memory elements, to store a data digit that can take any of at least three different values.