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    • 5. 发明授权
    • Switchable FET distortion generator
    • 可切换FET失真发生器
    • US5162748A
    • 1992-11-10
    • US799659
    • 1991-11-29
    • Allen Katz
    • Allen Katz
    • H03F1/32
    • H03F1/3241H03F2200/372H03F2200/72
    • A communications system includes a transmission channel in which, for efficiency, a processor such as an amplifier is operated in a nonlinear mode. When the signal is modulated in a manner which is affected by the nonlinearity of the processor, such as a multicarrier modulation, a distortion linearizer is used. The distortion linearizer incluees the source-to-drain conductive channel of a FET. The gate of the FET is coupled to ground by an impedance which may be a low inductance, and the gate is biased relative to the channel, possibly near pinchoff, to cause the channel to exhibit desirable gain expansion and phase shifts in response to signal input level, which are selected to compensate the distortion of the nonlinear processor. When the signal is modulated in a manner which is not significantly affected by the nonlinearity of the processor, as for example frequency modulation, the distortion linearizer is switched to a linear or ON mode, in which the amplitude and phase are invariant with signal level. The switching is accomplished by adjusting the gate-to-channel voltage.
    • 通信系统包括传输信道,其中为了效率,诸如放大器的处理器以非线性模式操作。 当以受处理器非线性影响的方式(如多载波调制)调制信号时,使用失真线性化。 失真线性化电路暴露了FET的源极到漏极导电沟道。 FET的栅极通过可能是低电感的阻抗耦合到地,并且栅极相对于沟道偏置,可能接近于尖峰,使得沟道响应于信号输入而呈现期望的增益扩展和相移 电平,被选择以补偿非线性处理器的失真。 当以不受处理器的非线性的显着影响的方式(例如频率调制)来调制信号时,失真线性化器被切换到线性或ON模式,其中幅度和相位与信号电平不变。 通过调整栅极到沟道电压来实现开关。
    • 6. 发明授权
    • Travelling-wave tube protection arrangement
    • 行波管保护装置
    • US5500621A
    • 1996-03-19
    • US416111
    • 1995-04-03
    • Allen KatzHerbert J. WolksteinJames J. Meighan, III
    • Allen KatzHerbert J. WolksteinJames J. Meighan, III
    • H01J25/38H03F1/54H03F3/58
    • H01J25/38H01J23/34H03F1/54H03F3/58
    • A travelling-wave tube (TWT) for a satellite communication system includes a cathode current regulator which compares a sensed I.sub.K signal with a cathode current reference to form an cathode current error signal, and controls the cathode current in response to the cathode current error signal. Helix arc protection is provided by a helix current shut-down, which compares the helix current with a particular reference, and shuts the TWT supply down when helix current flows. Desirable high efficiency TWTs have a small input drive range between maximum TWT output and a defocussed condition, in which beam current flows in the helix. Sudden changes in path attenuation may result in an RF overdrive condition, and cause helix current flow, and undesirably shut down the TWT. A helix current limiter senses the helix current, and compares it with a reference which represents less helix current than that which causes shutdown, to produce a helix current error signal. The helix current error signal adjusts the cathode current reference, to thereby reduce the cathode current in a feedback manner, to thereby tend to maintain the helix current constant at a value below the shut-down helix current.
    • 用于卫星通信系统的行波管(TWT)包括阴极电流调节器,其将感测到的IK信号与阴极电流参考值进行比较以形成阴极电流误差信号,并响应于阴极电流误差信号来控制阴极电流 。 螺旋电弧保护由螺旋电流关闭提供,其将螺旋电流与特定参考值进行比较,并在螺旋电流流动时关闭TWT电源。 期望的高效率TWT在最大TWT输出和散焦条件之间具有小的输入驱动范围,其中束电流在螺旋中流动。 路径衰减的突然变化可能导致RF过驱动条件,并导致螺旋电流流动,并且不期望地关闭TWT。 螺旋电流限制器检测螺旋电流,并将其与参考相比较,该参考表示比引起关闭的螺旋电流更少的螺旋电流,以产生螺旋电流误差信号。 螺旋电流误差信号调节阴极电流参考,从而以反馈方式减小阴极电流,从而倾向于将螺旋电流恒定在低于停机螺旋电流的值。
    • 7. 发明授权
    • Wideband transmission-mode FET linearizer
    • 宽带传输模式FET线性化
    • US5191338A
    • 1993-03-02
    • US800375
    • 1991-11-29
    • Allen KatzShabbir S. Moochalla
    • Allen KatzShabbir S. Moochalla
    • H03H11/18H03F1/32H03F3/60H03G1/00H03G3/20H04B7/15
    • H03G3/3036H03F1/3241H03F3/601H03G1/0029H03F2200/372H03F2200/72
    • A FET is operated without source-to-drain bias, with the source-to-drain conductive path coupled in series with a transmission line. A gate-to-ground impedance is selected in conjunction with a gate voltage near pinchoff to impress nonlinear distortion or gain and/or phase of signals traversing the source-to-drain conductive path. The nonlinear distortion can compensate for the amplitude distortion of a following amplifier, but the phase distortion may not be suitable for correcting that of the following amplifier. An inductor is bridged from source to drain, and corrects the phase without excessive effect on the amplitude. The magnitude of the inductor may be adjusted to minimize nonlinear amplitude change without affecting the phase change, whereupon the phase change may be made independent of amplitude change. A resistor in series with the bridging inductor can be selected to render amplitude change independent of phase change. Two such independent amplitude and phase correctors may be cascaded.
    • 在没有源极到漏极偏置的情况下操作FET,其中源极 - 漏极导电路径与传输线串联耦合。 栅极对地阻抗被选择在靠近pinchoff处的栅极电压,以施加穿过源极 - 漏极导电路径的信号的非线性失真或增益和/或相位。 非线性失真可以补偿后续放大器的幅度失真,但是相位失真可能不适用于校正后续放大器的失真。 电感从源极到漏极桥接,并校正相位,而不会对幅度产生过大的影响。 可以调节电感器的幅度以使非线性幅度变化最小化,而不影响相位变化,因此相位变化可以独立于振幅变化。 可以选择与桥接电感器串联的电阻器,以使幅度变化与相变无关。 两个这样独立的振幅和相位校正器可以级联。
    • 10. 发明授权
    • Amplifier and driver system with multichannel operation
    • 具有多通道运算的放大器和驱动器系统
    • US5990750A
    • 1999-11-23
    • US39907
    • 1998-03-16
    • Allen Katz
    • Allen Katz
    • H03F1/32H03F3/68H02H7/20H03F3/04
    • H03F1/3241
    • An RF amplifier includes a FET output stage and a driver. The FET is subject to long-term degradation in multiple-carrier use if its average gate current often exceeds a predetermined value. The random superposition of signal peaks of the multicarrier signal may cause such peaks to occur. The driver stage is selected to provide a range of four dB or less between the single-signal 1 dB compression point and the hard compression point, as measured by driver input signal level. This prevents application of excessive input signal to the output stage in a multicarrier situation, and prevents degradation of the FETs of the output stage. In one embodiment, a predistortion equalizer or linearizer is placed before the driver stage, to tend to linearize the characteristic of the driver and output stage combination at signal levels below those at which the driver is limited.
    • RF放大器包括FET输出级和驱动器。 如果平均栅极电流通常超过预定值,则FET在多载波使用中会长期恶化。 多载波信号的信号峰值的随机叠加可能导致发生这种峰值。 选择驱动级,以提供单信号1 dB压缩点和硬压缩点之间的4 dB或更小的范围,由驱动器输入信号电平测量。 这防止了在多载波情况下向输出级施加过大的输入信号,并且防止了输出级的FET的劣化。 在一个实施例中,将预失真均衡器或线性化器放置在驱动器级之前,倾向于将信号电平的信号电平低于驱动器受限的信号线性化,使驱动器和输出级组合的特性线性化。