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公开(公告)号：US11251787B2
公开(公告)日：2022-02-15
申请号：US16998789
申请日：2020-08-20
Inventor： John Paul Lesso
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.
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公开(公告)号：US11206487B2
公开(公告)日：2021-12-21
申请号：US16709075
申请日：2019-12-10
Inventor： John Paul Lesso , Mark James Mccloy-Stevens , John Bruce Bowlerwell , Yanto Suryono , Xin Zhao , Morgan Timothy Prior
Abstract: This application relates to audio driving circuitry (100), and in particular to audio driving circuitry for outputting first and second audio driving signals for driving a stereo audio load (106), which may be a stereo audio load of an accessory apparatus (102) removably coupled to the audio driving circuitry in use. A load monitor (111) is provided for monitoring to monitor, from a monitoring node (112), an indication of a common mode return current passing through a common return path, together with an indication of a common mode component of the first and second audio driving signals and to determine an impedance characteristic of the stereo audio load. The load monitor (111) can provide dynamic monitoring of any significant change in load impedance. In some embodiments the load monitor (111) comprises an adaptive filter (301) which adapts a parameter of the filter which is related to the load impedance so as to determine the indication of load impedance.
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公开(公告)号：US11164588B2
公开(公告)日：2021-11-02
申请号：US16940014
申请日：2020-07-27
Inventor： César Alonso , John Paul Lesso
IPC: G10L17/22 , G10L25/03 , H04L9/32 , H04L29/06 , G06F21/32 , H04K1/00 , H04W12/122 , G06F21/55 , H04R1/40 , G10L21/0216 , G10L25/78 , G07C9/37 , G10L17/10 , H04R3/00
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.
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公开(公告)号：US11121690B2
公开(公告)日：2021-09-14
申请号：US16552843
申请日：2019-08-27
Inventor： John Paul Lesso , Toru Ido
Abstract: This application relates to Class D amplifier circuits. A modulator controls a Class D output stage based on a modulator input signal (Dm) to generate an output signal (Vout) which is representative of an input signal (Din). An error block, which may comprise an ADC, generates an error signal (ε) from the output signal and the input signal. In various embodiments the extent to which the error signal (ε) contributes to the modulator input signal (Dm) is variable based on an indication of the amplitude of the input signal (Din). The error signal may be received at a first input of a signal selector block. The input signal may be received at a second input of the signal selector block. The signal selector block may be operable in first and second modes of operation, wherein in the first mode the modulator input signal is based at least in part on the error signal; and in the second mode the modulator input signal is based on the digital input signal and is independent of the error signal. The error signal can be used to reduce distortion at high signal levels but is not used at low signal levels and so the noise floor at low signal levels does not depend on the component of the error block.
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公开(公告)号：US11042618B2
公开(公告)日：2021-06-22
申请号：US16028964
申请日：2018-07-06
Inventor： John Paul Lesso
IPC: G06F7/04 , G06F21/32 , G06F17/30 , G10K11/178 , G06F16/23 , G06F21/40 , G10L17/00 , G10L17/24 , G10L17/10
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.
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Patent Agency Ranking
公开(公告)号：US11018186B2
公开(公告)日：2021-05-25
申请号：US16781157
申请日：2020-02-04
Inventor： John Paul Lesso
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.
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公开(公告)号：US10997981B2
公开(公告)日：2021-05-04
申请号：US16122033
申请日：2018-09-05
Inventor： John Paul Lesso
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.
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公开(公告)号：US10984268B2
公开(公告)日：2021-04-20
申请号：US16157634
申请日：2018-10-11
Inventor： John Paul Lesso
IPC: G06K9/00 , G10L17/00 , G01S15/88 , G01S7/539 , G01S15/58 , G01S7/52 , G06K9/22 , G10L25/51 , G10L25/03 , G10L25/66
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.
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公开(公告)号：US10950245B2
公开(公告)日：2021-03-16
申请号：US15666267
申请日：2017-08-01
Inventor： John Laurence Melanson , John Paul Lesso
Abstract: This application describes methods and apparatus for generating a prompt to be presented to a user for the user to vocalise as part of speaker recognition. An apparatus according to an embodiment has a selector for selecting at least one vocal prompt element to form at least part of said prompt from a predetermined set of a plurality of vocal prompt elements. The selector is configured to select the vocal prompt element based, at least partly, on an indication of the operating conditions for the biometric speaker recognition, for example background noise. The prompt is selected to be one which will provide a good likelihood of discrimination between users when vocalised and used for speaker recognition in the current operating conditions. The prompt may be issued as part of a verification process for an existing user or an enrolment process for an enrolling user.
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公开(公告)号：US10904684B2
公开(公告)日：2021-01-26
申请号：US16190455
申请日：2018-11-14
Inventor： John Paul Lesso
IPC: H03K3/0233 , G04F10/00 , H04R29/00 , H03M1/50 , H03K7/08
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.
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