Abstract: A system for thermally protecting an amplifier driving a capacitive load may include a low-pass filter configured to filter, with a variable cutoff frequency, an input signal to generate a filtered input signal, wherein the amplifier is configured to receive the filtered input signal and amplify the filtered input signal to generate a driving signal to the capacitive load and a controller configured to receive a real-time estimate of a temperature associated with the amplifier and vary the variable cutoff frequency as a function of the temperature.

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: 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: A method may include receiving a stream of serial pulse-density modulation (PDM) data representing a first channel of data synchronized with a rising edge of a clock associated with the serial PDM data and a second channel of data synchronized with a falling edge of the clock, wherein each of the first channel of data and the second channel of data include encoded datagrams wherein each encoded datagram comprises more than one digital bit, detecting an invalid state associated with the stream, and responsive to detecting the invalid state, determining boundaries of each encoded datagram of the stream based on where within the stream the invalid state occurred.

Abstract: A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.

Abstract: A system may include an input configured to receive a digital audio input signal having at least four and fewer than 65,000 quantization levels and sampled at at least 500 kilohertz, a low-pass filter configured to receive the digital audio input signal and perform filtering on the digital audio input signal to generate a filtered digital audio input signal having a bandwidth of between approximately 100 hertz and 10 kilohertz, a digital-to-analog converter configured to receive the filtered digital audio input signal and convert the filtered digital audio input signal into an equivalent analog audio input signal, and a driver configured to receive the equivalent analog audio input signal and drive an analog audio output signal to a transducer, wherein a group delay from the input to an output of the driver is less than 50 microseconds.

Abstract: A method for use in speaker verification, comprises: receiving a sample of a person's speech; estimating a noise measure in the received sample of the person's speech; if the estimated noise measure does not meet a predetermined criterion, rejecting the received sample of the person's speech; and if the estimated noise measure meets the predetermined criterion: adding noise to the received sample to form a sample with increased noise; extracting features of the sample with increased noise; and forming a model of the person's speech from the extracted features.

Abstract: A system may include an input configured to receive a first signal representative of a second signal to be driven to an amplifier input of an amplifier, processing circuitry configured to process the first signal in order to generate the second signal from the first signal such that the processing circuitry limits a current driven by the amplifier to an output load of the amplifier, and an output configured to drive the second signal to the amplifier input.

Abstract: Received data representing speech is stored, and a trigger detection block detects a presence of data representing a trigger phrase in the received data. In response, a first part of the stored data representing at least a part of the trigger phrase is supplied to an adaptive speech enhancement block, which is trained on the first part of the stored data to derive adapted parameters for the speech enhancement block. A second part of the stored data, overlapping with the first part of the stored data, is supplied to the adaptive speech enhancement block operating with said adapted parameters, to form enhanced stored data. A second trigger phrase detection block detects the presence of data representing the trigger phrase in the enhanced stored data. In response, enhanced speech data are output from the speech enhancement block for further processing, such as speech recognition.

Abstract: A system may include a driver for driving an output signal to a load, a pre-driver for driving a pre-driver signal to the driver, the pre-driver having a variable drive strength, and a controller configured to control the variable drive strength based on at least one measured physical quantity to compensate for variation of an output signal edge rate due to variations in the at least one measured physical quantity.

Abstract: A DC-DC converter and corresponding method for transitioning between a discontinuous conduction mode, DCM, and a continuous conduction mode, CCM, wherein the DC-DC converter is configured to power a signal processing system within an integrated circuit, is provided. The method comprises receiving input data, wherein the input data is for inputting into the signal processing system; determining an amplitude of the input data; and transitioning between DCM and CCM based on the amplitude of the input data. A DC-DC converter and respective method for transitioning from CCM to DCM comprising determining an estimated current representative of an inductor current through an inductor of the DC-DC converter; and transitioning from CCM to DCM based on the estimated current, is provided.

Abstract: The application describes MEMS transducers having a patterned membrane electrode which incorporates a plurality of openings or voids. A conductive element is provided on the surface of the underlying membrane within the opening.

Abstract: A speaker recognition system for authenticating a mobile device user includes an enrollment and learning software module, a voice biometric authentication software module, and a secure software application. Upon request by a user of the mobile device, the enrollment and learning software module displays text prompts to the user, receives speech utterances from the user, and produces a voice biometric print. The enrollment and training software module determines when a voice biometric print has met at least a quality threshold before storing it on the mobile device. The secure software application prompts a user requiring authentication to repeat an utterance based at least on an attribute of a selected voice biometric print, receives a corresponding utterance, requests the voice biometric authentication software module to verify the identity of the second user using the utterance, and, if the user is authenticated, imports the voice biometric print.

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, generating the slope compensation signal to have a compensation value of approximately zero as seen by a compensation control loop of the switch-mode power supply, and modifying the slope compensation signal on successive switching cycles of the switch-mode power supply to account for differences in an output of the compensation control loop and an average current of an inductor of the switch-mode power supply in at least one phase of a switching period of a switching cycle of the switch-mode power supply.

Abstract: An integrated haptic system may include a digital signal processor and an amplifier communicatively coupled to the digital signal processor and integrated with the digital signal processor into the integrated haptic system. The digital signal processor may be configured to receive a force sensor signal indicative of a force applied to a force sensor and generate a haptic playback signal responsive to the force. The amplifier may be configured to amplify the haptic playback signal and drive a vibrational actuator communicatively coupled to the amplifier with the haptic playback signal as amplified by the amplifier.

Abstract: A package for a MEMS device, the package comprising a MEMS transducer within a chamber of the package; and a package substrate, wherein an upper surface of the package substrate defines at least part of a surface of the chamber; wherein the package substrate comprises a plurality of metal layers, the package substrate further comprising at least a part of a filter circuit for filtering RF signals, wherein a first metal layer is provided in a first plane of the substrate and wherein a resistor of the filter circuit is provided in a plane below the first plane.

Abstract: A method of fabricating a piezoelectric transducer may include interleaving a plurality of layers of piezoelectric material with a plurality of conductive layers including a first conductive layer, one or more second conductive layers, and one or more third conductive layers, coupling the first conductive layer to a first electrode, wherein an electrical impedance of the first conductive layer varies as a function of a temperature internal to the piezoelectric transducer, and such that a measurement signal indicative of the electrical impedance is generated at the first electrode, coupling the one or more second conductive layers to a second electrode, and coupling the one or more third conductive layers to a third electrode, such that an electrical driving signal driven to the second electrode and the third electrode causes mechanical vibration of the piezoelectric transducer as a function of the electrical driving signal.

Abstract: A method for generating a periodic ramp waveform may include in a sampling phase of each period of operation of a ramp-generation circuit, sampling a reference voltage onto a sampling capacitor. The method may also include in a transfer phase of each period of operation of the ramp-generation circuit: discharging the reference voltage from the sampling capacitor through at least one resistor to generate a current and generating the periodic ramp waveform by integrating the current with at least one integrating capacitor, wherein a duration of the transfer phase is significantly smaller than a time constant defined by a capacitance of the sampling capacitor and a resistance of the at least one resistor, such that the reference voltage discharges linearly from the sampling capacitor as a function of time during the transfer phase.

Abstract: The present application relates to MEMS transducer comprising a membrane electrode and a backplate electrode. The membrane electrode comprises primary and secondary openings.

Abstract: A polymorphic playback system is disclosed in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path, wherein the polymorphic playback system may include a lower-latency detection filter, a higher-latency detection filter, and a control subsystem that uses the lower-latency detection filter for detecting the one or more first characteristics of the playback signal and uses the higher-latency detection filter for detecting the one or more second characteristics of the playback signal.