Intermodulation Effects in Limiter Amplifier Repeaters

Abstract

A method is presented for analyzing intermodulation (IM) spectra in limiting amplifiers using a statistical approach. Engineering approximations are derived for the case of a large number of input signals. The accuracy appears to be good down to seven signals. The approach permits analysis of arbitrary locations (in frequency) of the input signals. Possible ways of reducing IM interference in limiting satellite repeaters are discussed. The analysis is generally restricted to the ideal hard-limiting amplifier however, its applicability to other nonlinear characteristics is illustrated. Additional sources of degradation, such as amplitudemodulation-frequency-modulation (AM-FM) conversion and system phase nonlinearity, are not treated.