Radio receiver

摘要

A radio pager for receiving FSK signals has optimally narrow gaussian bandpass filters (F1, F2) and a phase lock loop (11, 12, 13, 14) for preventing local oscillator drift controlled in dependence of the derivation frequency (+/-4.5 KHz) which is accurately controlled at the transmitter and which is derived from the decoder logic circuit (20). A significant increase in sensitivity is achieved over existing pagers.