Requirements Justification to Digital Signal Synthesizers for Various Types of Radar Systems

Abstract

The paper justifies the requirements for the level of distortion of radar stations with pulse and quasi-continuous radiation, built on the basis of digital signal synthesizers of four types: digital synthesizers of voltage counts and digital synthesizers of phase counts with uniform sampling, digital synthesizers of voltage counts and digital synthesizers of phase counts with uneven sampling. When building a radar master device, the question arises about choosing the type of digital signal synthesizer. The main initial criteria are the maximum operating range of the digital synthesizer and the level of in-band distortion. When choosing the type of digital signal synthesizer, you have to take into account a large number of factors, the main of which are the complexity of the execution of the digital readout shaper, the possibility of implementing a digital readout shaper with the required speed and number of digits [1, 2]. When making requirements for the total level of distortion, the criterion of acceptable reduction of the probability of correct detection in comparison with its potential value for a fixed probability of false alarm is used. Based on this criterion, in pulse radars, the maximum relative RMS value of the distortion of the intercorrelation function of a signal with angular modulation generated by a digital synthesizer should not exceed Dδx ≤ –(51...67) dB. In a radar with quasi-continuous radiation, the maximum relative mean-square value of the distortion of the autocorrelation function of the signal with angular modulation should not exceed Dδ ≤ –(80...120) dB. The number of bits of phase quantization, voltage and time delay compensation in digital signal synthesizers depends not only on the maximum relative RMS value of the distortion of the intercorrelation function, but also on the number of samples of the signal with angular modulation. Therefore, initially you need to select the reference frequency of the digital signal synthesizer, setting the type of modulation and the effective spectrum width of the signal with angular modulation based on the tactical and technical characteristics radar