19 Jan
2022
19 Jan
'22
5:20 a.m.
Jay Hennigan wrote:
Radar receivers are typically some form of direct conversion with rather good selectivity, synchronized to the frequency of the transmitted pulse.
No. Direct conversion stage has no inherent frequency selectivity and is subject to saturation by noise of any frequency unless the noise is removed in advance. Selectivity can be enjoyed only after successful unsaturated conversion, direct or to IF. But, the solution is to put an LC band pass/stop filter between an antenna and a receiver, though I have no idea on the difficulty to obtain FAA/FCC approval to do so. Masataka Ohta