Carrier frequency assignment for nonlinear repeaters
Abstract
Selective carrier frequency spacing is required in some space and mobile systems to reduce the effects of intermodulation interference due to the nonlinear characteristics of a common amplifier. This paper expresses the frequency assignment problem of avoiding or minimizing third-order intermodulation interference in terms of difference sets, thus permitting a definition of the concept of optimum frequency plans, an efficient assessment technique applicable to systems having constraints that preclude the use of ideal plans, and a connection with certain problems in coding and graph theory whose results are used to provide frequency plans superior to those previously published. The difference set concept is also extended to allow the generation of fifth-order intermodulation-free frequency assignments, and frequency planning examples are provided using plots of intermodulation spectra.
- Publication:
-
COMSAT Technical Review
- Pub Date:
- May 1977
- Bibcode:
- 1977COMTR...7..227F
- Keywords:
-
- Carrier Frequencies;
- Communication Satellites;
- Frequency Assignment;
- Intermodulation;
- Mathematical Models;
- Repeaters;
- Broadband Amplifiers;
- Channels (Data Transmission);
- Coding;
- Traveling Wave Amplifiers;
- Communications and Radar