Investigation and measurement of aircraft communication system immunity

This paper considers immunity of a military airborne communication system against low and high power interfering signals in accordance with standards for aeronautical radio stations operating in VHF band 117.975-136.975 MHz and UHF band 225-400 MHz. Our intention here is to highlight test procedures of certain receiver parameters mainly according to the standards: RTCA DO-186A; and MIL-STD-188-243. Receiver immunity against undesired reception channels is given by its frequency response which is determined by the receiver selectivity and spurious response rejection. We are contemplating issues of interference and immunity of an aircraft communication system against high-power signals originating in power electronic circuits of aircraft power systems. This paper presents measurements of the AM receiver selectivity, spurious response rejection, intermodulation response rejection, desensitization as well as the EMC issue. The proposed automated measurement setup using the graphical language environment VEEPro is shown in this paper.