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    NOISE CANCELLATION SYSTEM
    1.
    发明申请
    NOISE CANCELLATION SYSTEM 审中-公开
    噪声消除系统

    公开(公告)号：WO2009156756A3

    公开(公告)日：2011-01-06

    申请号：PCT/GB2009050720

    申请日：2009-06-24

    Applicant: WOLFSON MICROELECTRONICS PLC ,  MAGRATH ANTHONY JAMES ,  GRAHAM CLIVE ROBERT

    Inventor： MAGRATH ANTHONY JAMES ,  GRAHAM CLIVE ROBERT

    IPC: G10K11/178 ,  G10L21/02 ,  G10L21/0208 ,  G10L21/0216

    CPC classification number: G10K11/178 ,  G10K2210/1053 ,  G10K2210/1081 ,  G10K2210/3027 ,  G10L21/0208 ,  G10L2021/02082 ,  G10L2021/02165 ,  H03H21/0012

    Abstract: A noise cancellation system for an audio system such as a mobile phone handset, or a wireless phone headset has a first input for receiving a first audio signal from one or more microphone positioned to receive ambient noise, and a second input for receiving a second audio signal from a microphone positioned to detect the user?s speech, as well as a third input for receiving a third audio signal for example representing the speech of a person to whom the user is talking. A first noise cancellation block receives the first audio signal and generates a first noise cancellation signal, and this is combined with the third audio signal to form a first audio output signal. A second noise cancellation block receives at least a part of the first audio signal and said second audio signal and applying noise cancellation to generate a second audio output signal.

    Abstract translation: 用于诸如移动电话听筒或无线电话耳机的音频系统的噪声消除系统具有用于从被定位成接收环境噪声的一个或多个麦克风接收第一音频信号的第一输入端和用于接收第二音频的第二输入端 来自定位成检测用户语音的麦克风的信号，以及用于接收第三音频信号的第三输入，例如表示用户正在说话的人的语音。 第一噪声消除块接收第一音频信号并产生第一噪声消除信号，并将其与第三音频信号组合以形成第一音频输出信号。 第二噪声消除块接收第一音频信号和所述第二音频信号的至少一部分并且施加噪声消除以产生第二音频输出信号。

    FEEDBACK CONTROLLER FOR PWM AMPLIFIER
    2.
    发明申请
    FEEDBACK CONTROLLER FOR PWM AMPLIFIER 审中-公开
    PWM放大器的反馈控制器

    公开(公告)号：WO2007020404A9

    公开(公告)日：2007-06-14

    申请号：PCT/GB2006003014

    申请日：2006-08-11

    Applicant: WOLFSON MICROELECTRONICS PLC ,  MAGRATH ANTHONY JAMES ,  WESTLAKE JOHN

    Inventor： MAGRATH ANTHONY JAMES ,  WESTLAKE JOHN

    IPC: H03F3/217 ,  H03F1/32 ,  H03F1/34 ,  H03F3/30

    CPC classification number: H03F3/30 ,  H03F1/32 ,  H03F1/3217 ,  H03F1/34 ,  H03F3/217 ,  H03F3/2173 ,  H03F2200/351 ,  H03F2200/78

    Abstract: A feedback controller in a PWM amplifier comprises a signal input for receiving a pulse width modulated (PWM) input signal (Vin) whose duty cycle represents a desired analogue output signal. A feedback loop filter (518) generates a filtered error signal (Vint) comprising a filtered representation of differences between the input signal (Vin) and a feedback signal (Vfb). A comparator (520) compares the filtered error signal with a reference to generate a provisional PWM switching control signal (C) for controlling the PWM amplifier (500). A pulse conditioner (532) receives both the provisional PWM switching control signal (C) and the PWM input signal (X=Vin) and outputs to the amplifier (500) a conditioned PWM switching control signal (Y), modified in accordance with predetermined constraints in relation to the PWM input signal.

    Abstract translation: PWM放大器中的反馈控制器包括用于接收其占空比表示期望的模拟输出信号的脉宽调制（PWM）输入信号（Vin）的信号输入端。 反馈环路滤波器（518）生成包括输入信号（Vin）与反馈信号（Vfb）之间的差的滤波表示的滤波误差信号（Vint）。 比较器（520）将滤波后的误差信号与参考值进行比较以生成用于控制PWM放大器（500）的临时PWM切换控制信号（C）。 脉冲调节器（532）接收临时PWM开关控制信号（C）和PWM输入信号（X = Vin）并且向放大器（500）输出根据预定值修改的调节PWM开关控制信号（Y） 与PWM输入信号有关的限制。

    Sample rate converter
    5.
    发明专利
    Sample rate converter 未知

    公开(公告)号：GB2456360B

    公开(公告)日：2009-12-02

    申请号：GB0818759

    申请日：2008-10-13

    Applicant: WOLFSON MICROELECTRONICS PLC

    Inventor： MAGRATH ANTHONY JAMES

    IPC: H03H17/06

    Abstract: A sample rate converter circuit receives a first signal at a first sampling frequency and for outputs a second signal, representative of the first signal, having a second sampling frequency. The sample rate converter comprises: a buffer, for storing data samples received from said first signal; a first loop circuit, for receiving a first clock signal corresponding to the first sampling frequency and a second clock signal corresponding to the second sampling frequency, and for generating an estimate of a ratio of the first sampling frequency to the second sampling frequency; and a second loop circuit, for receiving the first clock signal, the second clock signal and the estimate of the ratio of the first sampling frequency to the second sampling frequency, and for outputting a write pointer so that the data samples can be stored in the buffer, and for outputting a read pointer so that the data samples can be read from the buffer, with a first offset between the read pointer and the write pointer, such that the first offset is substantially independent of the ratio of the first sampling frequency to the second sampling frequency.

    Noise cancellation system
    6.
    发明专利
    Noise cancellation system 未知

    公开(公告)号：GB2461315B

    公开(公告)日：2011-09-14

    申请号：GB0811863

    申请日：2008-06-27

    Applicant: WOLFSON MICROELECTRONICS PLC

    Inventor： MAGRATH ANTHONY JAMES ,  GRAHAM CLIVE ROBERT

    IPC: G10K11/178 ,  G10K11/175 ,  G10L21/02 ,  G10L21/0208 ,  G10L21/0216 ,  H03H21/00 ,  H04R3/00

    Abstract: A noise cancellation system for an audio system such as a mobile phone handset, or a wireless phone headset has a first input for receiving a first audio signal from one or more microphone positioned to receive ambient noise, and a second input for receiving a second audio signal from a microphone positioned to detect the user's speech, as well as a third input for receiving a third audio signal for example representing the speech of a person to whom the user is talking. A first noise cancellation block receives the first audio signal and generates a first noise cancellation signal, and this is combined with the third audio signal to form a first audio output signal. A second noise cancellation block receives at least a part of the first audio signal and said second audio signal and applying noise cancellation to generate a second audio output signal.

    Infinite impulse response filter
    8.
    发明专利
    Infinite impulse response filter 未知

    公开(公告)号：GB2455806A

    公开(公告)日：2009-06-24

    申请号：GB0725116

    申请日：2007-12-21

    Applicant: WOLFSON MICROELECTRONICS PLC

    Inventor： CLEMOW RICHARD ,  MAGRATH ANTHONY JAMES

    IPC: H03H17/04 ,  H03H17/02

    Abstract: An infinite impulse response (IIR) filter for receiving an input signal and outputting a filtered signal comprises feedback circuitry 50 for feeding back said filtered signal, the feedback circuitry comprising a first delay element 52 for delaying said filtered signal; and a sub-unit 70, for receiving said delayed filtered signal, for outputting a summed signal, generated by an adding element 82, which is the difference between said delayed filtered signal and a further-delayed filtered signal, and for outputting a multiplied signal, generated by a multiplier 60, which is an inverted further-delayed filtered signal multiplied by a first filter coefficient H1. At least said input signal, said delayed filtered signal, said multiplied signal, and said summed signal are employed to generate said filtered signal. The filter is particularly suitable for use with an over-sampled input signal.

    Pulse width modulator quantisation circuit
    9.
    发明专利
    Pulse width modulator quantisation circuit 未知

    公开(公告)号：GB2449591B

    公开(公告)日：2009-03-18

    申请号：GB0816236

    申请日：2005-01-17

    Applicant: WOLFSON MICROELECTRONICS PLC

    Inventor： MAGRATH ANTHONY JAMES

    IPC: H03M5/08 ,  H03F3/217 ,  H03M1/82 ,  H03M7/32

    Abstract: The present invention relates to pulse width modulation (PWM) modulators, especially but not exclusively for digital audio applications; and to quantizers and power switching for the same. The present invention provides a pulse width modulation (PWM) modulator or converter having a guard band quantizer arranged to block low level signal inputs to the modulator in order to prevent narrow width output pulses. This arrangement is particularly advantageous when applied to tri-level PWM modulators, but can also be applied to other level PWM modulators such as bi-level for example. Quantization noise can be reduced by implementing the quantizer in a noise shaper circuit (or possibly a SDM) having loop feedback.

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