The Automatic Generator of Super-High Frequencies with Optical Control

The investigations of characteristics of the superhigh frequency oscillator are represented on the basis of transistor structure consisting of bipolar transistors of one type of admittance. The opportunity, both optical, and electric frequency control of generation, is shown. The expansion of a tuning frequency range of generation of self-excited oscillators of superhigh frequencies is one of major problems at their design. One of paths of the decision of this problem is the variation of equivalent capacity of a tuning circuit of UHF of the oscillator and dynamic negative resistance canceling power losses in the tuning circuit. The variation of these parameters is possible through action of optical radiation on a photosensitive diode switched on in a circuit of backward positive communication of the self-excited oscillator. On Fig. 1 the circuit of the self-excited oscillator is represented. It represents a hybrid integrated circuit consisting of three bipolar transistors, three resistors, capacity, inductance and photosensitive diode. Such circuit implements the self-excited oscillator of superhigh frequencies with optical frequency control of generation. The tuning circuit consists of inductance L1 and equivalent capacity of a complete resistance existing on electrodes of a collector and the emitter of the bipolar transistor VT2. The variation of power of optical radiation from 0 up to 120 uWt/cm2 reduces in a frequency change of generation on 70 MHz at supply voltage of 5 V. The greatest sensitivity makes 1.15 MHz/uWt/cm2 and lays in a range from 5 uWt/cm2 up to 60uWt/cm2.