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Development of a coded 16-ary CPFSK coherent demodulatorTheory and hardware are described for a proof-of-concept 16-ary continuous phase frequency shift keying (16-CPFSK) digital modem. The 16 frequencies are spaced every 1/16th baud rate for 2 bits/sec/Hz operation. Overall rate 3/4 convolutional coding is incorporated. The demodulator differs significantly from typical quadrature phase detector approaches in that phase is coherently measured by processing the baseband output of a frequency discriminator. Baud rate phase samples from the baseband processor are decoded to yield the original data stream. The method of encoding onto the 16-ary phase nodes, together with convolutional coding gain, results in near quad PSK (QPSK) performance. The modulated signal is of constant envelope; thus the power amplifier can be saturated for peak performance. The spectrum is inherently bandlimited and requires no RF filter.
Document ID
19880016342
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Clarke, Ken (Harris Corp. Melbourne, FL, United States)
Davis, Robert (Harris Corp. Melbourne, FL, United States)
Roesch, Jim (Harris Corp. Melbourne, FL, United States)
Date Acquired
September 5, 2013
Publication Date
May 1, 1988
Publication Information
Publication: Jet Propulsion Lab., Proceedings of the Mobile Satellite Conference
Subject Category
Communications And Radar
Accession Number
88N25726
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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