Квазистационарный анализ подавления нелинейных искажений в СВЧ усилителях с помощью коррекции по огибающей сигнала
The suppression of the nonlinear distortions in amplifier using the effect of the envelope signal of the amplified HF oscillations on the amplifier parameters is analyzed. A slow (on the time scale of the HF oscillations) variation in the parameters gives rise to additional frequency components of oscillations that compensate for the nonlinear distortions of the original signal. Several variants to employ the compensating signal using the feedback circuits in the transistor amplifiers and variations in the electron-beam current in TWT in the absence of such circuits are considered. The suppression of the nonlinear intermodulation distortions (IMDs) of the test two_frequency signal is studied for the above variants and the suppression of the third_order IMD by 6–19 dB corresponds to the known experimental data on the microwave transistor amplifier. The generalization of the quasistationary method for the analysis of the nonlinear transformation of signals allows the analysis of the amplification and suppression of IMD for more complicated multifrequency signals that are used in radio systems.
The transmission of а complex signal through nonlinear structures (semiconductor diodes, high-power transistor amplifiers, microwave vacuum amplifiers, ets.) is investigated by means of quasi-stationary method, and functional models of devices are applied. The models use the quasi-stationary method of analysis of multifrequency signal transformation. Certain properties and peculiarities that are exhibited by nonlinear devices and that induce so-called spectrum multiplexing, i.e., formation of combination components, including those observed within the basic spectrum, are considered. The possibilities of spectrum multiplexing in nonlinear elements with a polynomial quadratic, cubic, or more complicated characteristic are discussed.