Noise Characteristics of the Sounding Signal Generator for Geodynamic Monitoring Systems of the Geological Environment Based on Geoelectric Control Methods

Abstract

The work is devoted to the study of the noise characteristics of the probing signals generator for geodynamic monitoring systems of the geological environment based on geoelectric control methods implemented on the basis of a digital digital synthesizer (DDS). It is shown that the main sources of phase noise of the DDS are the clock signal generator, taking into account its transmission coefficient, as well as synthesizer links, and the phase noise of the DDS itself consists of two components: quantization noise and the device's own noise. To reduce their level, as well as generally improve the spectral characteristics of the genetator, it is proposed to use the principle of automatic compensation of phase distortions, its scheme with deviation control is obtained. Based on this scheme, as well as expressions of transfer functions, a mathematical model of the noise characteristics is obtained. A highly stable HCMOS/TTL quartz oscillator was used as a reference generator for the simulation, and an AD9854 integrated synthesizer was used as a DDS. Using their models, graphs of the spectral density of the phase noise of the sounding signal generator are obtained. The noise contributions of the component links and the degree of automatic phase noise compensation for various values of the amplifier gain of the autocompensator are obtained.