A Symmetric Telemetry Diversity Combiner System

Abstract

Phase-tracking discontinuities produced by switching transients in the usual Master/Slave telemetry diversity combiners under deep-fade conditions, can create data loss in modern, phase-modulated telemetry systems. This paper presents an innovative, dual-channel diversity combining system that overcomes this deficiency, has improved phase noise performance, and maintains full optimal ratio combining for PM, FM, and PSK modulated PCM telemetry. This is accomplished by a symmetric architecture that does not rely on either of the two input channels as a master reference to which the other is phase locked. The new design has the added advantage that the phase noise of a weak master channel is not superimposed on a stronger slave channel.