Worst Case Model for Fast Analysis of Intermodulation Interference in Radio Receiver

Abstract

A behavioral model for analysis of intermodulation interference that may arise in a radio receiver operating in complicated electromagnetic environment is developed. The model makes it possible to predict the levels of unequal-power multi-signal intermodulation interference (generated by involving the receiver input signals and the local oscillator signal, including its main tone and harmonics) on the basis of information about the levels of receiver susceptibility to mixer-generated spurious responses and to two-signal intermodulation of different kinds and orders. The model combines the worst case nature of intermodulation level prediction (which is a distinctive feature of conventional methods for analysis of intermodulation) with the high speed of computations (which is implemented by the use of the discrete nonlinear analysis technology). The experimental analysis of intermodulation interference in the AOR AR5000 receiver is performed in order to validate the developed model; the measurements were implemented with the use of the double-frequency test technique, which makes it possible to detect all kinds of two-signal intermodulation interference arising in a receiver.