公开(公告)号：US5065451A

公开(公告)日：1991-11-12

申请号：US363863

申请日：1989-06-09

申请人： Howard Leveque

发明人： Howard Leveque

IPC分类号： H04B14/00 ,  H04B1/64

CPC分类号： H04B1/64

摘要： A linked compressor-expander (Lincompex) circuit for use in telecommunications utilizes a frequency compensation circuit to frequency shift the total bandwidth of the whole communication channel to eliminate single side band "duck-talk" and data distortion in the transmitting of a complex waveform due to frequency drift or the detuning of the transmitter/receiver system. The demodulator includes an expander for expanding the compressed voice or data signal and a control tone conversion circuit for converting the received control tone into a frequency signal to be used by the expander. The control tone conversion circuit also determines the frequency error of a combination information waveform so that the frequency compensation circuit can carry out the proper frequency shifting process. A fading regulator is also provided to remove any audible level variations not removed by the automatic gain control circuitry in the receiver.

公开(公告)号：US4894862A

公开(公告)日：1990-01-16

申请号：US222432

申请日：1988-07-19

申请人： Bruno Defretin ,  Thierry Arnaud

发明人： Bruno Defretin ,  Thierry Arnaud

IPC分类号： H03G7/00 ,  H03M7/30 ,  H04B1/64 ,  H04M1/60

CPC分类号： H04B1/64 ,  H03G7/002 ,  H04M1/6033

摘要： The Invention relates to a signal compression circuit, more particularly for a telephone set of the handsfree-type, comprising a preamplifier (10), the input of which is connected with an input signal to be processed, and a preamplifier gain control device (11) for servo-controlling, to a predetermined value, the output signal amplitude of the preamplifier, in which the gain control device (11) is associated with a circuit (C, 15, 16) determining two time constants, which respectively control the increase or decrease speed of the preamplifier gain (10) in relation with the input signal amplitude (Vin).

摘要翻译： 本发明涉及一种信号压缩电路，更具体地说，涉及一种免提型电话机，包括前置放大器（10），其输入端与要处理的输入信号相连，以及前置放大器增益控制装置（11 ），用于伺服控制预定值，其中增益控制装置（11）与确定两个时间常数的电路（C，15,16）相关联的前置放大器的输出信号幅度，其分别控制增加 或相对于输入信号幅度（Vin）降低前置放大器增益（10）的速度。

公开(公告)号：US4862118A

公开(公告)日：1989-08-29

申请号：US105288

申请日：1987-10-07

申请人： Masanori Kojima

发明人： Masanori Kojima

IPC分类号： G11B20/04 ,  H03G7/00 ,  H03G9/02 ,  H04B1/64

CPC分类号： H03G7/002 ,  H03G9/025

摘要： In a signal processing system used for recording and reproducing acoustic signals, a compressor comprises a first detector for detecting an output signal from an amplifier by a first time constant, a second detector for detecting the output signal from the amplifier by a second time constant which is shorter than the first time constant, a threshold means for detecting a signal from the second detector to output a signal component exceeding a threshold level, and a combining means for combining signals from both the first detector and the threshold to thereby generate an output to the amplifier. An expander in the signal processing system comprises a first detector for detecting an input signal to be inputted into an amplifier by a first time constant, a second detector for detecting the input signal to the amplifier by a second time constant which is shorter than the first time constant, a threshold means for detecting a signal from the second detector to output a signal component exceeding a threshold level, and a combining means for combining signals from both the first detector and the threshold means to thereby generate a signal to the amplifier.

摘要翻译： 在用于记录和再现声信号的信号处理系统中，压缩器包括用于以第一时间常数检测来自放大器的输出信号的第一检测器，用于从第二时间常数检测来自放大器的输出信号的第二检测器， 小于第一时间常数的阈值装置，用于检测来自第二检测器的信号以输出超过阈值电平的信号分量的阈值装置，以及用于组合来自第一检测器和阈值的信号的组合装置，从而产生输出 放大器。 信号处理系统中的扩展器包括：第一检测器，用于检测要以第一时间常数输入到放大器中的输入信号;第二检测器，用于以比第一时间常数短的第二时间常数检测放大器的输入信号; 时间常数，用于检测来自第二检测器的信号以输出超过阈值电平的信号分量的阈值装置，以及用于组合来自第一检测器和阈值装置的信号的组合装置，从而产生到放大器的信号。

公开(公告)号：US4839906A

公开(公告)日：1989-06-13

申请号：US196235

申请日：1988-05-20

申请人： James H. Leveque ,  Frederick A. Williams ,  John Eldon

发明人： James H. Leveque ,  Frederick A. Williams ,  John Eldon

IPC分类号： H04B14/00 ,  H03M7/30 ,  H04B1/64 ,  H04J3/18

CPC分类号： H04J3/18 ,  H03M7/30

摘要： A digital linked compressor-expander telecommunications system (Lincompex), is implemented using a general purpose digital signal processor wherein the compression and expansion functions are performed by blocks of programmed code. Input audio analog signals are converted to parallel data digital signals thereupon the digitial signals are input for processing. After processing, the resultant signals are passed to a 16-bit digital-to-analog converter where either the compressed or expanded digital voice data signal is converted back into an audio frequency analog signal for either transmission or communication on an output device.

公开(公告)号：US4701722A

公开(公告)日：1987-10-20

申请号：US744965

申请日：1985-06-17

申请人： Ray M. Dolby

发明人： Ray M. Dolby

IPC分类号： H03G7/00 ,  H03G9/02 ,  H04B1/62 ,  H04B1/64

CPC分类号： H03G9/025

摘要： Circuits for modifying the dynamic range of signals, particularly compressors and expanders for use in noise reduction compander systems, in which the advantages of fixed band characteristics (variable attenuation throughout all or part of the frequency band) and sliding band characteristics (variable attenuation through part of the frequency band achieved by a variable pass filter) are provided, without the disadvantages normally inherent in each characteristic. Fixed band and sliding band circuit elements are operated either in parallel or in series, the elements operating in generally the same level range and at least a partial overlapping in frequency range.

摘要翻译： 用于修改信号的动态范围的电路，特别是用于降噪压缩扩展器系统中的压缩机和扩展器的电路，其中固定频带特性的优点（全部或部分频带的可变衰减）和滑带特性（通过部分的可变衰减 提供了通过可变通滤波器实现的频带），而没有每个特性通常固有的缺点。 固定频带和滑带电路元件并联或串联操作，元件在大致相同的电平范围内工作，并且在频率范围内至少部分重叠。

公开(公告)号：US4683449A

公开(公告)日：1987-07-28

申请号：US729781

申请日：1985-05-02

申请人： Shigeru Kato

发明人： Shigeru Kato

IPC分类号： H03G7/00 ,  H03G9/02 ,  H04B1/64

CPC分类号： H03G9/025 ,  H03G7/002

摘要： A noise reduction system which is unaffected by bandwidth limitations of the transmission system with which the noise reduction system is employed. The noise reduction system is of a type including a compressor, the transmission system, which receives a compressed signal from the compressor, and an expander for expanding a signal outputted by the transmission system. In accordance with the invention, a low-pass filter having a pass band corresponding to the transmission band of the transmission system is provided in the stage prior to the compressor. In another embodiment, a low-pass filter is provided in a stage prior to a level detector within the compressor.

摘要翻译： 一种降噪系统，不受采用噪声降低系统的传输系统的带宽限制的影响。 噪声降低系统是包括压缩机，从压缩机接收压缩信号的传输系统和用于扩展由传输系统输出的信号的扩展器的类型。 根据本发明，在压缩机之前的阶段提供具有与传输系统的传输频带对应的通带的低通滤波器。 在另一个实施例中，在压缩机内的电平检测器之前的阶段提供低通滤波器。

公开(公告)号：US4647876A

公开(公告)日：1987-03-03

申请号：US705356

申请日：1985-02-25

申请人： James Waller, Jr.

发明人： James Waller, Jr.

IPC分类号： H03G9/02 ,  H04B1/64

CPC分类号： H03G9/025

摘要： A noise reduction system compresses an input signal at a constant ratio in response to a control signal derived from the compressed signal. Added to the derived control signal is a counterfeit control signal which causes the compressor to mistrack when the compressed signal falls below a preselected threshold level. Thus, low level compressor output signals are increasingly deemphasized. A constant counterfeit control signal produces a logarithmic decrease in compressor output signal levels below the threshold point. The resulting compressed signal is used in two ways to enhance system noise reduction. First, the compressed signal is expanded at a constant ratio over all signal levels so that low level mistracked signals are further deemphasized and the system noise floor is lowered. Second, the expanded signal is fed to a filter having a variable bandwidth controlled by a signal derived from the compressed signal and responsive to compressed signal frequency and amplitude so that the filter is desensitized to input signal amplitude changes. A multistage filter control signal arrangement may be employed to provide variable cutoffs in more than one bandwidth.

摘要翻译： 响应于从压缩信号导出的控制信号，降噪系统以恒定比例压缩输入信号。 加到导出的控制信号中的是一种假冒控制信号，当压缩信号下降到预先选择的阈值水平以下时，该控制信号使压缩器发生误差。 因此，低压缩机输出信号越来越被强调。 恒定的假冒控制信号产生低于阈值点的压缩机输出信号电平的对数减小。 所产生的压缩信号以两种方式用于增强系统降噪。 首先，压缩信号在所有信号电平上以恒定比例扩展，使得低电平失真信号被进一步降低，并且降低系统本底噪声。 第二，扩展信号被馈送到具有由从压缩信号导出的信号控制的可变带宽的滤波器，并且响应于压缩的信号频率和振幅，使得滤波器被减弱以输入信号幅度变化。 可以采用多级滤波器控制信号布置来在多于一个带宽中提供可变截止。

公开(公告)号：US4573208A

公开(公告)日：1986-02-25

申请号：US558046

申请日：1984-01-26

申请人： Paul H. Jacobs ,  Douglas P. Collette

发明人： Paul H. Jacobs ,  Douglas P. Collette

IPC分类号： H04B1/64 ,  H04B1/68 ,  H04B1/76 ,  H04B7/00

CPC分类号： H04B1/64 ,  H04B1/68

摘要： A compressed single side band communication system and method in which the audio signal is compressed prior to pre-emphasis and thereafter summed with a pilot tone for further compression prior to transmission. Initially, only the pilot tone is transmitted at full rated power to aid in acquisition of the signal by the receiver. Thereafter, the transmitter ALC is disabled and the pilot tone is attenuated. The receiver adjusts the frequency characteristics of the pilot tone filter and phase lock loop filter in the detector as a function of lock-on. The delay after loss of lock-on in reverting to wide band pilot tone and wideband loop filters is varied as a function of signal strength. The pilot tone may be modulated for tone coded squelch. The modulating source is located in the return end of the phase lock loop filter. A unique filter is provided to insure acquisition of the pilot tone. Automatic gain control of the audio signal is responsive to the tone signal without affecting the composite audio and tone signal.

摘要翻译： 一种压缩单边带通信系统和方法，其中音频信号在预加重之前被压缩，然后在传输之前与用于进一步压缩的导频音相加。 最初，只有导频音以全额定功率传输，以帮助接收机获取信号。 此后，发射机ALC被禁用并且导频音被衰减。 接收机调节检测器中导频音滤波器和锁相环滤波器的频率特性，作为锁定功能。 作为信号强度的函数，响应于宽带导频和宽带环路滤波器的锁定失去锁定之后的延迟是变化的。 可以对导频音进行调制，进行音调编码的静噪。 调制源位于锁相环滤波器的返回端。 提供一个唯一的滤波器来确保采集导频音。 音频信号的自动增益控制响应于音调信号而不影响复合音频和音调信号。

公开(公告)号：US4562571A

公开(公告)日：1985-12-31

申请号：US558888

申请日：1983-12-07

申请人： Pierre Deman ,  Jean Potage

发明人： Pierre Deman ,  Jean Potage

IPC分类号： H04B1/64 ,  H04B3/20

CPC分类号： H04B1/64

摘要： The device is of the type comprising a circuit for compressing the dynamic of the speech signal before transmission of the signal at constant level and an expander for re-establishing at reception the speech level before compression thereof. A logic filtering circuit controls the compression circuit by constant attenuation steps depending on the speech level. A selector comparator circuit coupled by a first input to an output of the logic filtering circuit and by a second input to the output of a device controlling the expander compares the attenuation values supplied by the logic filtering circuit with those supplied by the device controlling the expander and adjusts the attenuation value of the compression circuit to the greatest of the attenuation values supplied by the logic filtering circuit or by the control device of the expander.

摘要翻译： 该装置的类型包括用于在传输恒定电平的信号之前压缩语音信号的动态的电路和用于在接收压缩之前在接收处重新建立语音电平的扩展器。 逻辑滤波电路根据语音电平通过恒定的衰减步骤控制压缩电路。 通过第一输入耦合到逻辑滤波电路的输出并通过第二输入耦合到控制扩展器的器件的输出的选择器比较器电路将由逻辑滤波电路提供的衰减值与由控制扩展器的器件提供的衰减值进行比较 并且将压缩电路的衰减值调整到由逻辑滤波电路或扩展器的控制装置提供的最大衰减值。

公开(公告)号：US4485483A

公开(公告)日：1984-11-27

申请号：US476738

申请日：1983-03-18

申请人： Emil L. Torick ,  Thomas B. Keller

发明人： Emil L. Torick ,  Thomas B. Keller

IPC分类号： H03G7/00 ,  H04B1/64 ,  H04H20060101 ,  H04H1/00 ,  H04H20/48 ,  H04H20/88 ,  H04H5/00

CPC分类号： H04H20/48 ,  H03G7/00 ,  H04B1/64

摘要： An FM stereophonic radio broadcasting system in which stereophonically related audio frequency source signals L and R are matrixed to obtain stereophonic sum and difference signals M and S, respectively. At the transmitter, the difference signal, is compressed, and the conventional difference signal and the compressed difference signal modulate respective quadrature-related sub-carriers of the same frequency to develop two double-sideband, suppressed-carrier signals, the frequency of the sub-carriers being sufficiently high as to assure a frequency gap between the lower sidebands of the modulated sub-carrier signals and the sum signal M. The M signal, the aforementioned suppressed-carrier signals, and a pilot signal having a frequency which lies within the frequency gap, are combined and frequency-modulated onto a high frequency carrier for the purpose of transmitting the same to one or more remote receivers. The receiver includes an expander for complementarily expanding the received compressed difference signal, and the expanded noise-reduced difference signal is combined with the received sum signal to reproduce the audio frequency source signals L and R. The system increases the broadcast coverage area over that of current biphonic service yet is compatible with existing monophonic and biphonic receivers.

摘要翻译： 立体声相关的音频源信号L和R被矩阵化的FM立体声无线电广播系统分别获得立体声和差分信号M和S。 在发射机处，差分信号被压缩，并且传统的差分信号和压缩的差分信号调制相同频率的各个正交相关子载波以产生两个双边带，抑制载波信号，子频率 载波足够高以确保调制的子载波信号的下边带与和信号M之间的频率间隙.M信号，前述的抑制载波信号和具有位于该信号中的频率的导频信号 频率间隙被组合和频率调制到高频载波上，以将其发送到一个或多个远程接收机。 接收机包括用于互补地扩展接收的压缩差分信号的扩展器，并且扩展的降噪差信号与接收到的和信号相组合，以再现音频源信号L和R.系统增加广播覆盖区域超过 目前的双声道服务与现有的单声道和双声道接收机兼容。