NTRS - NASA Technical Reports Server

Back to Results
Performance of the unique-word-reverse-modulation type demodulator for mobile satellite communicationsThis paper proposes a new type of coherent demodulator, the unique-word (UW)-reverse-modulation type demodulator, for burst signal controlled by voice operated transmitter (VOX) in mobile satellite communication channels. The demodulator has three individual circuits: a pre-detection signal combiner, a pre-detection UW detector, and a UW-reverse-modulation type demodulator. The pre-detection signal combiner combines signal sequences received by two antennas and improves bit energy-to-noise power density ratio (E(sub b)/N(sub 0)) 2.5 dB to yield 10(exp -3) average bit error rate (BER) when carrier power-to-multipath power ratio (CMR) is 15 dB. The pre-detection UW detector improves UW detection probability when the frequency offset is large. The UW-reverse-modulation type demodulator realizes a maximum pull-in frequency of 3.9 kHz, the pull-in time is 2.4 seconds and frequency error is less than 20 Hz. The performances of this demodulator are confirmed through computer simulations and its effect is clarified in real-time experiments at a bit rate of 16.8 kbps using a digital signal processor (DSP).
Document ID
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Dohi, Tomohiro
(Nippon Telegraph and Telephone Public Corp. Yokosuka, Japan)
Nitta, Kazumasa
(Nippon Telegraph and Telephone Public Corp. Yokosuka, Japan)
Ueda, Takashi
(Nippon Telegraph and Telephone Public Corp. Yokosuka, Japan)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: JPL, Proceedings of the Third International Mobile Satellite Conference (IMSC 1993)
Subject Category
Communications And Radar
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
No Preview Available