LASER DIODE MODULATION UNDER MULTICHANNEL DIGITAL 64-QAM AND 256-QAM TV SIGNALS
V. A. Vardanyan
Siberian State University of Telecommunications and Informatics, ul. Kirova 86, Novosibirsk 630102, Russia
Keywords: клиппирование, отношение сигнал/шум, поднесущий ТВ-канал, clipping, signal/noise ratio, subcarrier TV channel
Abstract
A simulation model for laser diode modulation by multichannel 64-QAM and 256-QAM TV signals is developed. The signal/noise (S/N) ratio is used as a criterion for evaluating the quality of TV signals. The effect of nonlinearity of the light-current characteristic on the S/N ratio is studied. Simulation results are presented in the form of a dependence of the maximum number of transmitted channels on the optical modulation depth with certain requirements for S/N. The simulation model is implemented in the object-oriented programming language Delphi 7.
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