Title :
A Stabilized Narrow-Band Frequency-Modulation System for Duplex Working
Author_Institution :
Radio Section, Chief Engineer´´s Office, Post and Telegraph Department, Wellington C. 1, New Zealand
Abstract :
A system is described whereby the two terminals of a duplex radiotelephone channel are stabilized against each other by the use of standard automatic-frequency-control circuits and the common use of an oscillator for both transmitting oscillator and superheterodyne high-frequency oscillator. The send and receive frequencies are separated from each other by an interval which is the frequency of the intermediate-frequency channel. The system can be designed to give adequate frequency stability for most applications without the use of crystal control.
Keywords :
Circuit stability; Communication channels; Control systems; Frequency modulation; Narrowband; Phase modulation; Radio transmitters; Radiofrequency integrated circuits; Ultra wideband communication; Voltage-controlled oscillators;
Journal_Title :
Proceedings of the IRE
DOI :
10.1109/JRPROC.1945.230504
