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517 条记录 (耗时 0.015 秒)

    Automatic gain control circuit
    81.
    发明授权
    Automatic gain control circuit 失效
    自动增益控制电路

    公开(公告)号：US4360929A

    公开(公告)日：1982-11-23

    申请号：US160325

    申请日：1980-06-17

    申请人： Mitsuo Isobe

    发明人： Mitsuo Isobe

    IPC分类号： H03G3/20 ,  H03G3/34 ,  H04N5/52

    CPC分类号： H03G3/3052 ,  H03G3/3068 ,  H03G3/34 ,  H04N5/52

    摘要： An AGC circuit includes an amplitude synchronous detector using a phase-locked loop (PLL), a variable gain amplifier for supplying a signal to this detector, and a means for controlling the amplification degree of the amplifier to make the output signal level constant. More specifically, the AGC circuit includes a first AGC loop including an AGC detector and a low-pass filter provided before the AGC detector, a second AGC loop including a synchronous detector and a phase synchronized state detecting circuit DC coupled to the output end of the synchronous detector, the output signal from the phase synchronized state detecting circuit being used to control the AGC circuit, and a noise eliminating circuit provided at the final stage for adding the output signal from the phase synchronized state detecting circuit and the output signal from the synchronous detector, or for performing subtraction between both the signals.

    摘要翻译： AGC电路包括使用锁相环（PLL）的振幅同步检测器，用于向该检测器提供信号的可变增益放大器，以及用于控制放大器的放大度以使输出信号电平恒定的装置。 更具体地说，AGC电路包括第一AGC环路，其包括AGC检测器和在AGC检测器之前提供的低通滤波器，第二AGC环路，包括同步检测器和相位同步状态检测电路DC，耦合到该输出端的输出端 来自相位同步状态检测电路的输出信号用于控制AGC电路，以及设置在最后级的噪声消除电路，用于将来自相位同步状态检测电路的输出信号和来自同步状态检测电路的输出信号相加 检测器，或用于在两个信号之间进行减法。

    Television intermediate frequency amplifier with feedback stabilization
    82.
    发明授权
    Television intermediate frequency amplifier with feedback stabilization 失效
    具有反馈稳定的电视中频放大器

    公开(公告)号：US4342005A

    公开(公告)日：1982-07-27

    申请号：US163144

    申请日：1980-06-26

    申请人： Jack R. Harford

    发明人： Jack R. Harford

    IPC分类号： H04N5/44 ,  H03G1/00 ,  H03G3/30 ,  H04N5/52

    CPC分类号： H04N5/52 ,  H03G1/0023 ,  H03G1/0082

    摘要： An I.F. amplifier is provided in which gain control is accomplished by varying the A.C. impedances of variable impedance devices, which devices are coupled as load and emitter degeneration impedances for amplifying transistors. Variable D.C. gain control currents are applied to the variable impedance devices to vary their impedance. Substantially all of the D.C. gain control currents flow through the variable impedance devices in current paths which are separate from the amplifying transistors, thereby avoiding variation of the operating points of the amplifying transistors. The I.F. amplifier includes a D.C. feedback path which does not require the use of feedback amplification, due to the lack of any changes in the operating points of the amplifying stages during gain control. Elimination of the need for feedback amplification also prevents the introduction of noise into the amplified I.F. signals.

    摘要翻译： 一个 放大器，其中通过改变可变阻抗器件的交流阻抗来实现增益控制，该可变阻抗器件耦合作为用于放大晶体管的负载和发射极退化阻抗。 可变直流增益控制电流被施加到可变阻抗器件以改变它们的阻抗。 基本上所有的直流增益控制电流流过与放大晶体管分开的电流路径中的可变阻抗器件，从而避免了放大晶体管工作点的变化。 I.F. 由于在增益控制期间放大级的工作点没有任何变化，放大器包括不需要使用反馈放大的直流反馈路径。 消除对反馈放大的需要也可以防止将噪声引入放大的I.F。 信号。

    Video signal processing circuit including lock-out prevention means for the intermediate frequency amplifier thereof
    83.
    发明授权
    Video signal processing circuit including lock-out prevention means for the intermediate frequency amplifier thereof 失效
    视频信号处理电路，包括用于其中频放大器的锁定防止装置

    公开(公告)号：US4209805A

    公开(公告)日：1980-06-24

    申请号：US920249

    申请日：1978-06-29

    申请人： Tsuneo Ikeda ,  Kenichi Tonomura

    发明人： Tsuneo Ikeda ,  Kenichi Tonomura

    IPC分类号： H03G3/20 ,  H03G3/30 ,  H04N5/52 ,  H04B1/16 ,  H04N5/14

    CPC分类号： H04N5/52 ,  H03G3/3068

    摘要： A video signal processing circuit adapted for use in TV receivers. The circuit includes an intermediate frequency amplifier circuit having signal amplifying transistors, a synchronous detection circuit adapted to produce the carrier signal and to produce a detection signal by making use of the reproduced carrier signal, a first gain control circuit adapted to deliver a gain control signal to the intermediate frequency amplifier circuit in accordance with the level of the detection signal and a second gain control circuit adapted to deliver a gain control signal to the intermediate frequency amplifier circuit in accordance with the level of the output from the latter. The second gain controller circuit is adapted to function to lower the gain of the intermediate frequency amplifier circuit, so as to recover the ordinary operating condition of the circuit, when the intermediate frequency amplifier circuit is undesirably locked at the full-gain condition during receiving of a broadcasting wave of a large electric field strength.

    摘要翻译： 适用于TV接收机的视频信号处理电路。 该电路包括具有信号放大晶体管的中频放大器电路，适于产生载波信号并通过利用再现的载波信号产生检测信号的同步检测电路，适于传送增益控制信号的第一增益控制电路 根据检测信号的电平到中频放大器电路，以及第二增益控制电路，其适于根据来自中频放大器电路的输出电平向中频放大器电路传送增益控制信号。 第二增益控制器电路用于降低中频放大器电路的增益，以便在接收到中频放大器电路期间在全增益条件下不期望地锁定时恢复电路的正常工作状态 具有大电场强度的广播波。

    Automatic gain control system and amplifier of controllable gain
    84.
    发明授权
    Automatic gain control system and amplifier of controllable gain 失效
    自动增益控制系统和可控增益放大器

    公开(公告)号：US3838210A

    公开(公告)日：1974-09-24

    申请号：US40207373

    申请日：1973-10-01

    申请人： GEN ELECTRIC

    发明人： PEIL W

    IPC分类号： H03G3/30 ,  H04N5/52

    CPC分类号： H04N5/52 ,  H03G3/3068

    摘要： An automatic gain control system incorporating a novel amplifier of controllable gain is described. The amplifier is d.c. coupled throughout and capable of wideband operation. It employs a cascoded differential transistor amplifier for producing the principal voltage gain supplemented by input and output emitter followers. Gain control is achieved by the application of gain control potentials to the bases of the upper rank transistors. Gain reduction is produced first in the upper rank by the controlled degeneration produced by a pair of nonlinear impedances in series with the emitter leads of the upper rank transistors, and sequentially in the lower rank transistors by the controlled degeneration produced by two pairs of nonlinear impedances coupled in a degenerative feedback path about the lower rank transistors and in the input circuit to a pair of input emitter followers. In addition, the amplifier produces an indication of gain control action which, when the amplifier is used as an intermediate frequency amplifier of a television system, permits one to derive a second gain control signal, which after thresholding may be used for further gain reduction in the tuner. The amplifier is adapted for integrated circuit fabrication.

    摘要翻译： 描述了包含可控增益的新型放大器的自动增益控制系统。 放大器是直流 并且能够进行宽带操作。 它采用级联差分晶体管放大器，用于产生由输入和输出发射极跟随器补充的主电压增益。 通过将增益控制电位应用于上级晶体管的基极来实现增益控制。 通过与上级晶体管的发射极引线串联的一对非线性阻抗产生的受控变性，并通过由两对非线性阻抗产生的受控变性依次产生在上级中的增益减小 耦合在围绕下级晶体管的退化反馈路径中，并且在输入电路中耦合到一对输入发射极跟随器。 此外，放大器产生增益控制动作的指示，当放大器用作电视系统的中频放大器时，允许一个导出第二增益控制信号，其在阈值之后可用于进一步增益减小 调谐器 该放大器适用于集成电路制造。