Effect of phase and range gate pull-off delay quantisation on jammer signal

Abstract

The analysis of jamming signals emitted by electronic countermeasure (ECM) systems after phase quantisation, performed by radio frequency digital memory devices, and after introduction of increasing time delay, is approached. The analysis shows the exact expression of the spectrum of a phase-quantised jamming signal when the quantisation levels are equally spaced. The spectrum of the signal presents a main term that is simply an attenuated version of the signal received by the ECM system, and spurious terms whose amplitude and position depend on the number of quantisation levels. The effect of time delay quantisation introduced by range gate pull-off devices is analytically evaluated, in combination to the phase quantisation. Results show that this second distortion can be generally neglected with respect to the spurious terms because of the phase quantisation, particularly when the number of phase quantisation bits is low.