TABLE OF CONTENTS DR. KAMILO FEHER
Professor, Electrical Engineering
University of California, Davis,
Davis, California 95616
and
Director, Consulting Group, DIGCOM, Inc.
A review of the principles of operation of frequently used digital modem techniques is followed by a description of recently developed power-efficient and spectrally efficient modems. For a particular terrestrial microwave, satellite, cable, wire, or other system application, the experienced system designer has a large number of candidate modem techniques at his or her disposal (See Table 7.1), which is an asset. The appropriate choice of a particular modulation technique will lead to the best system performance and to a lower-cost, more-competitive transmission subsystem. However, the less-experienced engineer could consider the large number of modem techniques, listed in Table 7.1, as a strange alphabet soup without significant meaning for his or her decision and system implementation.
| Abbreviation | Alternate abbreviation | Descriptive name of modem technique | |
|---|---|---|---|
| 1 | DSB-SC-AM | DSB-SC | Double-Sideband-Suppressed Carrier ? Amplitude Modulation |
| 2 | PSK | BPSK | Phase-Shift Keying; Binary-PSK |
| 3 | DPSK | DBPSK | Differential PSK; Differential Binary PSK ( no carrier recovery) |
| 4 | DEPSK | DEBPSK | Differentially Encoded PSK ( with carrier recovery) |
| 5 | QPSK | CQPSK | Quadrature (quaternary) PSK; Coherent QPSK |
| 6 | OQPSK | OKQPSK or SQPSK | Offset QPSK; Staggered QPSK |
| 7 | DQPSK | Differential QPSK ( no carrier recovery) | |
| 8 | DEQPSK | Differentially encoded QPSK ( with carrier recovery) | |
| 9 | MSK | FFSK | Minimum-shift keying; Fast-frequency-shift keying |
| 10 | DMSK |
