Dynamic features of autodyne signals

Abstract

Keywords: autodynes, autodyne oscillator, autodyne response, distortion parameter, autodyne response time constant, reflected signal, autodyne characteristics, direction of motion.In short-range Doppler radar systems, due to the simplicity of their design and low cost of the microwave module, autodynes (autodyne oscillators) are often used combining simultaneously functions of generators of probing radiation and receivers of reflected signals [1,2]. The operation principle of these devices is based on the autodyne effect peculiar to all oscillator types that is observed in the entire frequency range from radio to optical frequencies [2,3]. This effect consists in changes of the self-oscillation parameters under the influence of reflected signals. Registration of these changes in the form of autodyne signals and their subsequent processing make it possible to obtain information on the reflecting object and parameters of its relative motion.In the case of autodyne application for registration of the parameters of fast processes, for example, in experimental physics, combustion and explosion physics, indoor and outdoor ballistics, and other branches of science and technology [4,5], one faces the problem of allowance for the inertia of these devices. A large number of works are devoted to an analysis of the special features of signal formation under such conditions. The influence of inertia of oscillation amplitude changes [6] and oscillator anisochronous property was analyzed in [3,7]. In [8], in addition to the above-indicated oscillator properties, the non-isodromic oscillator property consisting in a dependence of the oscillation amplitude on the changes in the oscillation frequency was considered, and the special features of signal formation with allowance for the frequency dispersion of the autodyne frequency deviations and frequency auto-detection were studied. The condition of the validity of results of investigations common for the above-enumerated publications is a relatively short distances to the reflecting object for which the delay time τ of reflected signal is much less than the autodyne signal period a T

Autodyne Sensor Signals with Amplitude-Frequency Modulation of Radiation

“…Let us analyze the features of signal formation for the continuous AFM radiation regime described in (5) and (6) by the third members of the right-hand side. To identify the functions of the delayed action of , , and in these expressions, we perform their expansion into a Taylor series in the small parameter compared to the current time [ 31 , 32 ] where is, hereinafter, the serial number of the decomposition members and , are the factors due to the AM process and autodyne changes in the oscillation amplitude of the oscillator, respectively:…”