Performance of unbalanced QPSK in a nonlinear channel
Abstract
A possible way to relay information from remote-sensing satellites back to earth is through the use of a modified version of a QPSK modem. This paper investigates the performance of a regenerative unbalanced (UQPSK) system in linear and nonlinear channels. The performance degradation of a regenerative UQPSK system due to nonlinearities (TWTA) and filtering is assessed. Different filtering strategies are examined, and realistic values for the degradations resulting from nonlinear operation are obtained. It is shown that knowledge of the possible amount of degradations will help to reduce the modulator design complexity, because unreasonable margins will not have to be imposed. The necessary spectrum shaping to keep the degradations caused by the TWTA and bandpass filters at a low level are established.
- Publication:
-
Canadian Domestic and International Satellite Communications Conference
- Pub Date:
- 1984
- Bibcode:
- 1984cdsc.conf....5Y
- Keywords:
-
- Bit Error Rate;
- Channels (Data Transmission);
- Communication Satellites;
- Nonlinear Systems;
- Phase Shift Keying;
- Traveling Wave Amplifiers;
- Bandpass Filters;
- Computerized Simulation;
- Nonlinear Filters;
- Performance Prediction;
- Transmission Efficiency;
- Space Communications, Spacecraft Communications, Command and Tracking