Abstract

The paper presents the results of analysis of signal and noise characteristics of autodynes with frequency modulation. The mathematical model of autodyne is presented in the form of a self-oscillator with single-loop oscillation system that is frequency-tuned using the varicap. This model takes into account the impact of intrinsic radiation reflected from location object and the impact of generator internal noises on the oscillator. The paper investigates the relationship of the distortion degree of signal characteristics and the periodic nonstationarity of the root-mean-square value of the level of frequency and amplitude noises as a function of the distance to the location object and the value of external feedback parameter of the autodyne “generator–location object” system. It has been shown that at a small value of the parameter of external feedback, the signal characteristics are quasi-harmonic similar to homodyne type systems, while noises represent a stationary random process. If the value of external feedback parameter is comparable to unity, anharmonic distortions are observed in signal characteristics, while the periodic nonstationarity is observed in noise characteristics. It was established that with an increase of distance to the location object, when the delay time of reflected radiation became comparable or larger than the period of autodyne response, the degree of anharmonic distortions of signal characteristics and the height of peaks of root-mean-square noise level were significantly reduced. The results of experimental investigations have been obtained using the prototype of autodyne sensor with frequency modulation built on the 8-mm band Gunn diode.

中文翻译：

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Autodynes 的信号和噪声特性与作为到位置对象距离的函数的频率调制的关系

摘要

本文介绍了调频自测仪的信号和噪声特性分析结果。autodyne 的数学模型以具有单回路振荡系统的自振荡器的形式呈现，该系统使用变容二极管进行频率调谐。该模型考虑了从定位对象反射的固有辐射的影响以及发电机内部噪声对振荡器的影响。本文研究了信号特性的失真程度与频率和幅度噪声电平的均方根值随距定位目标距离和外部反馈参数值的周期性非平稳性之间的关系。 autodyne“生成器-定位对象”系统。已经表明，在较小的外部反馈参数值下，信号特性类似于零差型系统的准谐波，而噪声则代表平稳的随机过程。如果外部反馈参数的值与1相当，则在信号特征中观察到非谐波失真，而在噪声特征中观察到周期性非平稳性。已经确定，随着与定位目标距离的增加，当反射辐射的延迟时间变得可比或大于自达响应周期时，信号特征的非谐波失真程度和均值根峰值的高度方形噪音水平显着降低。