PHASE QUADRATURE FSK RECEIVER

摘要

A radio receiver for frequency shift keyed signals of the zero I.F. type. The quadrature outputs of mixers are low-pass filtered and a 90 DEG phase shift at the baseband frequency is introduced in one signal path. The baseband signals are then fully limited and applied to a logic network to provide a digital output indicative of the relative lead/lag condition of the two signal paths. The logic network can conveniently be an EXCLUSIVE-OR gate.