Pulse and Multifrequency Van der Pol Generators Based on Transistor Structures with Negative Differential Resistance for Infocommunication System Facilities

Abstract

The paper proposes new circuits of Van der Pol generators based on nonlinear and reactive properties of transistor structures with negative differential resistance, which operate in relaxation and quasi-periodic modes when parameters of their self-oscillating systems are controlled in a wide range. New analytical relations were obtained, which described parameters of sawtooth-shaped and rectangular voltage pulses of the relaxation-type Van der Pol generators, built on bipolar and field-effect transistor structures with negative differential resistance. A new multifrequency Van der Pol generator of quasi-periodic electrical oscillation based on a field-effect transistor structure with negative differential resistance was developed and its mathematical model was proposed. There were obtained analytical ratios for calculating the stationary oscillation amplitude in single-frequency and multifrequency modes, the critical detuning between single-frequency and multifrequency modes, as well as lower and upper cutoff frequencies of the operating frequency band. Phase portraits, time diagrams and amplitude spectra of electrical oscillations of the Van der Pol generators in oscillatory, relaxation and quasi-periodic modes were studied. Influence of parameters of the Van der Pol generators’ self-oscillating on generated oscillation dynamics was estimated.