The effects of quadrature sampling imbalances on a phase difference analysis technique

The effects of amplitude and phase imbalances between the in-phase and quadrature channels of a digital radio frequency (RF) receiver on a phase analysis processing technique are studied. Particular attention is given to the effect that these errors have on the detection and accurate frequency resolution of simultaneous signals. It is shown that these error effects can appear to be identical to a simultaneous signal condition. Thus using this technique in a practical electronic warfare (EW) receiver could cause incorrect conclusions unless the amplitude separation of the signals is small. Simulation results and data collected from a 250 MHz, 8 b digital receiver are presented to show how these errors, along with other anomalies, affect the performance of phase analysis processing, and specifically how they affect detection and determination of simultaneous signals