Effect of monotone interference on the performance of the combined active-passive microwave discriminator

This paper presents an analysis of the combined active-passive microwave discriminator when the input signal is accompanied by a monotone co-channel interference. The signal to interference power ratio (SIR) at the output of this discriminator has been calculated as a function of the input signal to interference power ratio, and the detuning of the monotone interference from the FM carrier. The signal to interference power ratio at the output of the discriminator has a typical value of 33 dB when the signal to interference power ratio at the input is 20 dB. The static frequency response of the discriminator has been experimentally measured in presence and in absence of the monotone interference. The interference is found to exert a pull on the frequency response of the discriminator towards itself.