S. M. Smolskiy

Main features of double-diode autodynes and its application

The results of the autodyne features for double-diode oscillator on Gunn diodes affected by the own reflected signal are presented. The main characteristics of such autodyne are considered oriented to the application in short-range radar systems. The brief description of the autodyne sensor for the determination of the loco movement parameters which is made on the basis of the double-diode autodyne.

The impact of resonator detuning on autodyne characteristics of stabilized microwave generators

Results of investigations of autodyne characteristics of microwave generators stabilized by an external high-Q resonator as a function of the oscillations frequency detuning and the natural frequency of the stabilizing resonator have been presented. Main mathematical expressions describing the autodyne response of generator to the impact of intrinsic radiation reflected from target were obtained. The design of the coupling between the main working and stabilizing resonators was implemented by using a circuit of band-reflecting filter with resistive coupling. The calculations of amplitude, frequency, and amplitude-frequency characteristics of the autodyne system were carried out under various conditions. The experimental data qualitatively corroborating the inferences of theoretical studies were obtained by investigating the case of a hybrid-integral 8-mm band Gunn oscillator.

Autodyne sensors for railway crossings

The autodyne sensor description on Gunn diode of 8-mm wave-length intended for detection of path occupation and the caps of the obstacle device for transport vehicles at guarded and non-guarded railway crossings is discussed.

Autodyne effect application for stability analysis of the steady-state mode of UHF oscillating systems

The autodyne characteristics are oifered to use for steady-state stability analysis of the UHF oscillators. Theoretical substantiation of the proposed method is performed on an example of the oscillating systems mathematical model presented in the form of two mutually-locked partial oscillators under a condition of strong coupling between them. Peculiarities of stable functioning zones for oscillating systems are described at different partial oscillator parameters and for various conditions of their mutual coupling. Experimental investigations are performed based on the 8mm-wavelength range double-diode oscillator.

Influence of the autodyne oscillator coupling degree with antenna upon its transfer and noise characteristics

Analysis results of coupling degree influence of the autodyne oscillator with an antenna are presented together with influence of the impedance characteristic type (soft or rigid) of the active element on the coefficients of autodyne amplification, autodyne frequency deviation and power transfer as well as on the noise parameters and characteristics. Analytical and numerical calculations of above-mentioned parameters and characteristics are performed, and results of experimental investigations of the 8mm-range Gunn diode autodyne are given.

Signal analysis of a double-diode autodyne

Analysis results of autodyne signals of the double-diode oscillator, which is under influence of the proper reflected emission from the moving object, are presented. The analysis is performed on the base of the autodyne mathematical model presented in the form of a system of two mutually-locked partial oscillators under condition of strong mutual coupling. Peculiarities of signal formation are considered for various parameters of partial oscillators and coupling conditions. Experimental data are obtained for the 8mm-range Gunn double-diode oscillator of the flange type.

Diffraction influence of reflected emission from the radar object upon autodyne radar signal formation

The new problem in the autodyne short-range radar theory is considered for the electrodynamics model on interaction of an oscillator with emission reflected from the radar object. The radar object is represented in the form of an arbitrary surface located in antenna emission field. The main relations for the analysis of diffraction influence of the reflected emission upon autodyne signal formation.

Influence of coupling between an oscillator and an antenna on autodyne transponder features in the frequency locking mode

Starting relations are obtained for the coupling influence analysis between an oscillator and an antenna for autodyne transponder features in the mode of frequency locking by the request radar signal. The operation speed investigation results show the dependence upon a coupling degree and the oscillator operation mode as well as on the value of the “softness” index of the impedance characteristic of an active element. Experimental results are obtained on the example of the transistor oscillator in the 15sm-wavelength range.

Circular wave-guide application experience in autodyne short-range radar of millimeter range

The description of construction with the advantages are shown for autodyne oscillators and antennas for short-range radar of millimeter range using the circular waveguides.

Temperature feature analysis of autodyne oscillators on gunn diode

Theoretical analysis fulfilled for temperature impact upon autodyne oscillators shows that this factor causes the self-oscillation condition changing first of all: namely, auto-bias, amplitude and frequency of oscillations, as well as output power. Temperature curves of the autodyne potential, its output levels of the signal and noise are determined by behavior of an autodyne gain factor, which in turn depends of the temperature variations of oscillator limit cycle fastness. Experimental research of autodyne properties, which is made on the basis of hybrid-integrated circuit ldquoTigel-08rdquo, shows that its potential and levels of output signal and noise in temperature range from -50 to +50deg C vary not more than 3 dB. Temperature frequency factor of these modules is (5.3-8) middot10-3 1/degree which corresponds with conventional microwave oscillators.