Theory and hardware emulation results are presented for a very flexible digitally implemented modem whose technology is useful over a broad class of satellite communications applications, both terrestrial and in-flight. The modem can be programmed for 2-, 4-, 8-, and 16-PSK (phase shift keying), 16-QAM (quadrature amplitude modulation), MSK (minimum shift keying), and offset-QPSK (quaternary PSK) modulation schemes over a range of data rates from 2.34 to 300 Mbit/s, with programmable spectral occupancy from 1.2 to 1.8 times the symbol rate. These operational parameters are executable in burst or continuous mode. All critical processing in both the modulator and demodulator is performed at baseband using very-high-speed digital hardware (including application-specific integrated circuits (ASICs)) and memory. Analog frontends in phase-quadrature are employed for translation between the IF and baseband, where the analog-to-digital conversion takes place.
A digitally implemented modem: theory and emulation results
Digital implementiertes Modem: Theorie und Emulationsergebnisse
Comsat Technical Review ; 22 , 1 ; 149-195
1992
47 Seiten, 17 Quellen
Aufsatz (Zeitschrift)
Englisch
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