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6 October 1989 4PPM Modulator/Demodulator With Fully Digital Signal Regeneration
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Proceedings Volume 1131, Optical Space Communication; (1989)
Event: 1989 International Congress on Optical Science and Engineering, 1989, Paris, France
The 4PPM modulator/demodulator was developed as a breadboard model for the SILEX project of the ESA. The most important requirements placed upon this equipment is that it has to operate with any of four bit rates between 15 and 120 Mbit/s with minimal switch-over facilities, and that the demodulator has to accept from the optical receiver front end signals that are considerably distorted by band limitation. While the 4PPM modulator consists of a rather simple digital circuit, operable at all four bit rates, the 4PPM demodulator is composed of four units: The Input Section with bit rate-specific switchable filters, the Flash Comparator, where the selected input signal is digitized and sampled, the Maximum Likelihood Detector by which the maximal amplitude time slot is selected, and where the 4PPM/NRZ transformation is performed, and the Word-Error Integrator where the word clock is adjusted to its proper phase.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
S. Boerner and J. Heichler "4PPM Modulator/Demodulator With Fully Digital Signal Regeneration", Proc. SPIE 1131, Optical Space Communication, (6 October 1989);

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