Detection of complex and simultaneous signals using an instantaneous frequency measurement receiver

IFM receivers using delay line discriminators for frequency measurement exhibit good performance characteristics in a pulsed signal environment. However, performance degrades for time-overlapped or complex signals. The paper presents an analysis with experimental verification for signal types such as pulsed, CW, linear FM and phase coded signals. More details are given for the case of two time-coincident pulsed signals. In addition, the effect of suppression of a weak signal by a stronger one in the limiting preamplifier as a function of overdrive is taken into account using a scaling factor.