ONE WAY DOPPLER EXTRACTOR, VOLUME ll-DIGITAL VCO TECHNIQUE

摘要

Volume II of this report presents a feasibility analysis and trade-offs for a One Way Doppler Extractor using digital VCO techniques. The method of doppler measurement involves the use of a digital phase lock loop. Once this loop is locked to the incoming signal, the precise frequency and hence the doppler component can be determined directly from the contents of the digital control register. Since the register size determines the system's quantization error, it can be made arbitrarily small by carrying a sufficient number of bits. Other errors are due to the signal to-noise ratio and the reference oscillator stability. The only serious error source is due to internally generated noise. Techniques are presented for minimizing this error source and achieving an accuracy of 0.01 Hz in a one second averaging period.nA number of digitally controlled oscillators are analyzed from a performance and complexity point of view. The most promising technique uses an arithmetic synthesizer as a digital waveform generator. RCA is currently designing an LSI array as part of an arithmetic synthesizer development using CMOS/SOS technology for minimum power dissipation at clock rates up to 20 MHz. A configuration of a One Way Doppler Extractor making use of this development is recommended for future exploitation.