Title :
A 150-Kc Carrier System for Radio Relay Applications
Author :
Boughtwood, J.E.
Author_Institution :
Assistant to transmission research engineer, engineering department, Western Union Telegraph Company, New York, N. Y.
Abstract :
The carrier system described was developed by the Western Union Telegraph Company for use with microwave radio relay circuits. Thirty-two voice-band communication channels, each 3,000 cycles wide, are derived in the frequency range 4 to 147 kc. Tandem stages of group modulators maintain a high degree of spectrum efficiency and eliminate the necessity for crystal filters. A crystal-controlled harmonic carrier supply insures the frequency stability required by narrow-band frequency-modulation telegraph circuits.
Keywords :
Circuit stability; Communication channels; Frequency; Microwave circuits; Microwave filters; Narrowband; Power harmonic filters; Radiofrequency integrated circuits; Relays; Telegraphy;
Journal_Title :
American Institute of Electrical Engineers, Transactions of the
DOI :
10.1109/T-AIEE.1948.5059714
