Метод оцінювання джитеру в цифрових радіоприймальних пристроях

Abstract

Виконано обґрунтований аналіз співвідношень для розрахунку рівня шумів та паразитних спектральних складових, що виникають через вплив джитеру тактових сигналів в аналого-цифрових та цифро-аналогових перетворювачах пристроїв первинного цифрового оброблення радіосигналів. Отримано прості аналітичні співвідношення для оцінювання середньоквадратичного значення шуму і амплітуди паразитних спектральних складових на виході АЦП для типових випадків взаємодії сигналу та джитеру.A substantiated analysis of correlations for calculating the noise level and parasitic spectral components that arise due to the influence of clock jitter in analogue-digital and digital-to-analogue converters of primary digital processing of radio signals is performed. The current level of development of the element base of antilog-to-digital converters during the implementation of algorithms for digital signal processing in radio receivers allows to increase the signal-to-noise ratio by simply increasing the bit of hardware and software. At the same time, the errors made by the ADC can not be adjusted with the help of secondary processing in radio receivers, and the improvement of the characteristics of these nodes is not quite an easy task. The influence of random phase shivering of clock signals (jitter) on the work of ADCs in radio receivers with the harmonic input signal is investigated. In particular, with the help of computer simulation, quantitative estimates of the influence of a harmonic jitter on the processing of the harmonic input signal in digital line link are obtained. The features of the operation of high-speed wide-range ADCs in the input line of radio receivers are examined on the basis of experimental studies for some individual cases. The method of estimating jitter in radio receiver devices for various cases of interaction of a signal and a jitter is offered. For the general case of signal interaction and jitter, the method of estimating the effects arising from the condition of the linearity of the main component of the error on both functions may consist in decomposition of functions on the elementary additive components and the evaluation of the effects for each component. Simple analytical relations were obtained for estimating the mean square noise and amplitude of parasitic spectral components at the output of the ADC for typical cases of signal and jitter interaction.