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公开(公告)号：US5469510A
公开(公告)日：1995-11-21
申请号：US82633
申请日：1993-06-28
申请人： Henry F. Blind , Anthony J. Campagne , James L. Czekaj , Nicholas L. Difiore , Earl R. Geddes , Andrew C. Krochmal , Myron I. Senyk
发明人： Henry F. Blind , Anthony J. Campagne , James L. Czekaj , Nicholas L. Difiore , Earl R. Geddes , Andrew C. Krochmal , Myron I. Senyk
IPC分类号： B60R11/02 , G10K11/178 , H03G3/20 , H03G3/32 , H03G5/16 , H03G9/02 , H03G11/00 , H03H17/00 , H03H21/00 , H04B3/04
摘要： An acoustic production system having multiple signal sources and a power amplifier driving an acoustic transducer such as a loudspeaker includes an arbitrator in a power limiter circuit to selectively limit the input level of one of the sources to the power amp in response to an overdrive signal from the amplifier. The input level to the power amplifier is automatically reduced in response to the overdrive signal until a predetermined level of limiting has been attained. Once the predetermined level of limiting is reached, the arbitrator outputs a second overdrive signal to prompt additional limiting of the power amplifier output. Preferably, the arbitrator is included in an interior active noise cancellation module combined with an audio entertainment system for a passenger compartment of a motor vehicle. The audio system also preferably separates the audio reproduction into high frequency and low frequency branches, whereby the arbitrator acts upon the signals output in the frequency ranges of active noise cancellation and the bass output of the audio entertainment system that are most likely to overdrive an amplifier.
摘要翻译： 具有多个信号源的声学生产系统和驱动诸如扬声器之类的声学换能器的功率放大器包括：功率限制器电路中的仲裁器，用于响应于来自第二个信号的过驱动信号选择性地将功率放大器的一个源的输入电平限制到功率放大器 放大器。 功率放大器的输入电平响应于过驱动信号而自动减小，直到达到预定的限制水平。 一旦达到预定的限制电平，则仲裁器输出第二过驱动信号以提示功率放大器输出的附加限制。 优选地，仲裁者被包括在与用于机动车辆的乘客舱的音频娱乐系统相结合的内部主动噪声消除模块中。 音频系统还优选地将音频再现分离成高频和低频分支，由此仲裁器对在最有可能过度驱动放大器的有源噪声消除和音频娱乐系统的低音输出的频率范围中输出的信号起作用 。
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公开(公告)号：US5208865A
公开(公告)日：1993-05-04
申请号：US812337
申请日：1991-12-23
IPC分类号： H03G3/34
摘要： Differential signals are employed in a distributed audio system to improve noise immunity of the low level differential signals transmitted between a main unit and a power amplifier. The power amplifier may be in an auxiliary output unit which is locally muted by employing a field-effect transistor connected between the differential signals. When the field-effect transistor is turned on by a mute signal, the common mode rejection of the differential amplifier is employed to mute the amplifier output.
摘要翻译： 在分布式音频系统中采用差分信号来提高在主单元和功率放大器之间传输的低电平差分信号的抗噪声能力。 功率放大器可以在辅助输出单元中，该辅助输出单元通过采用连接在差分信号之间的场效应晶体管来进行本地抑制。 当场效应晶体管通过静音信号导通时，采用差分放大器的共模抑制来使放大器输出静音。
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公开(公告)号：US5327101A
公开(公告)日：1994-07-05
申请号：US85369
申请日：1993-07-02
摘要： A distortion limiter for limiting the amount of distortion of an inverting amplifier is disclosed. A comparator produces a pulse when a signal level at an inverting input of the inverting amplifier exceeds a reference voltage level. The pulse charges a capacitor. When the charge on the capacitor is sufficient to raise the gate voltage of a junction field-effect transistor (FET) above cutoff, the FET shunts the input signal to reduce its level. The distortion characteristics can be controlled by using a voltage divider to adjust the voltage across the FET. A bias voltage at the gate of the FET, keeps the FET turned off when the inverting amplifier is not clipping.
摘要翻译： 公开了一种用于限制反相放大器的失真量的失真限制器。 当反相放大器的反相输入端的信号电平超过参考电压电平时，比较器产生脉冲。 脉冲对电容充电。 当电容器上的电荷足以将结型场效应晶体管（FET）的栅极电压提高到截止以上时，FET会分流输入信号以降低其电平。 可以通过使用分压器来调节FET两端的电压来控制失真特性。 在FET的栅极处的偏置电压，当反相放大器未被削波时，保持FET截止。
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公开(公告)号：US07202731B2
公开(公告)日：2007-04-10
申请号：US11155800
申请日：2005-06-17
IPC分类号： G01R19/00
CPC分类号： H03F1/3264 , H03G3/301
摘要： A system and method for predicting and limiting distortion of an amplified signal is described. The system includes a variable total harmonic distortion (“THD”) clipping predictor, a comparator in communication with the variable THD clipping predictor and a distortion limiter in communication with the comparator. As for the method, a reference power supply value, a maximum desired total harmonic distortion value and a preamplified signal value is provided. A THD output threshold value is calculated based on the reference power supply value and the maximum desired THD value and is then compared to the preamplified signal value. Depending on if the preamplified signal value is greater than or less than the THD output threshold value, the amplitude of the preamplified signal may be increased or decreased.
摘要翻译： 描述了用于预测和限制放大信号的失真的系统和方法。 该系统包括可变总谐波失真（“THD”）限幅预测器，与可变THD限幅预测器通信的比较器和与比较器通信的失真限制器。 对于该方法，提供参考电源值，最大期望总谐波失真值和预放大信号值。 基于参考电源值和最大期望THD值计算THD输出阈值，然后将其与前置放大信号值进行比较。 根据预放大信号值是否大于或小于THD输出阈值，可以增大或减小前置放大信号的幅度。
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公开(公告)号：US06870934B2
公开(公告)日：2005-03-22
申请号：US10195206
申请日：2002-07-15
CPC分类号： H04R29/001 , G01R31/2825 , H04R2420/05
摘要： The presence or absence of a speaker connected to an output terminal of an audio system is determined based on the electro-generator properties of the speaker. The audio system includes an output amplifier coupled to the output terminal. The method includes driving the output amplifier with a predetermined drive signal sufficient to produce a predetermined speaker excursion if a speaker is connected to the output terminal. The output amplifier is then isolated from the output terminal. A signal at the output terminal is sensed after the output amplifier is isolated. The sensed signal is compared with a predetermined reference for determining whether a speaker back-EMF is present. A speaker detection signal is generated indicating absence of a speaker if the back-EMF is not present.
摘要翻译： 连接到音频系统的输出端子的扬声器的存在或不存在基于扬声器的发电机特性来确定。 音频系统包括耦合到输出端的输出放大器。 该方法包括：如果扬声器连接到输出端，驱动具有足以产生预定扬声器偏移的预定驱动信号的输出放大器。 然后输出放大器与输出端子隔离。 在输出放大器隔离之后，检测输出端子处的信号。 将感测到的信号与用于确定扬声器反电动势是否存在的预定参考进行比较。 如果不存在反电动势，则产生指示扬声器不存在的扬声器检测信号。
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公开(公告)号：US06577737B1
公开(公告)日：2003-06-10
申请号：US09506295
申请日：2000-02-17
IPC分类号： H03G1100
摘要： A method of detecting a DC offset in an audio signal provided by an audio processing unit to an audio power amplifier, wherein the audio amplifier provides a clip detect signal back to the audio processing unit, wherein the method comprises the steps of sampling the clip detect signal to determine if the clip detect is active. Detecting a power level of the audio amplifier if the clip detect is active. Next, comparing the power level to a predetermined power threshold. Then, identifying a dc offset if the power level is less than the predetermined power threshold.
摘要翻译： 一种检测由音频处理单元提供给音频功率放大器的音频信号中的DC偏移的方法，其中音频放大器向音频处理单元提供一个片段检测信号，其中该方法包括以下步骤：对片段检测进行采样 信号以确定剪辑检测是否活动。 如果剪辑检测有效，则检测音频放大器的功率电平。 接下来，将功率电平与预定功率阈值进行比较。 然后，如果功率电平小于预定功率阈值，则识别直流偏移。
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