Nassir M. Increase in stability and reliability of linear frequency modulators on the base of inductive elements of transistor

The thesis aims at increase in stability of average frequency and linearity of the modulation characteristics of the frequency modulator in the range of high and ultrahigh frequencies, as well as at improvement of reliability by taking into account the manufacturing and technological deviations of scheme parameters components at the stage of designing. The thesis analyzes the methods for improving the stability of the average frequency of the frequency modulator based on quartz oscillators, using varicap as controlling element, as well as tunable oscillators with surface acoustic wave resonator. There had been considered the possibility of using solid state inductive ele-ments to compensate for instability in average frequency, stipulated for by the change in capacitance due to instability of power supply and temperature. There had been presented the researches of parameters of transistor inductive elements and the possibility of their use for the linearization of the modulation characteristics of frequency modulator. There had been developed the statistical models of the transistor inductive elements and frequency modulators on their base. It had been demonstrated that the probability density function parameters of transistor elements respond to the normal and are statistically dependent, and density function parameters probability frequency modulator can have arbitrary distributions of output parameters. To perform parametric optimization as for the criterion of maximum probability of ensuring the set output parameter (efficiency) there had been considered the possibility of converting arbitrary laws of distribution of output parameters with zero mean and unit standard deviation. There had been conducted the optimization of the parameters of the frequency modulator using Monte-Carlo method, the first and second density derived function as for the criteria of maximum probability of ensuring the performance. There had been considered the possibility for building the frequency manipulators and digital radio devices using the developed modulators. There had been designed the electric circuit of the frequency modulator with the stabilization of the average frequency and the linearization of the modulation characteristics on the basis of transistor inductive elements with the conducting the experimental researches.