Hybrid Amplitude-and-Phase Modulation for Analog Data Transmission

Author

Thomas, C. Melvil ; May, Curtis L. ; Welti, George R.

Author_Institution

TRW Systems, Inc., Redondo Beach, Calif., USA

Volume

23

Issue

6

fYear

1975

fDate

6/1/1975 12:00:00 AM

Firstpage

634

Lastpage

645

Abstract

Pulse-amplitude modulation (PAM) is extended to two and four dimensions by means of a nonlinear, memoryless mapping to obtain pulse-amplitude-and-phase modulation (PAPM). This modulation requires either the same bandwidth as double-sideband PAM or twice as much but yields a signal-to-noise ratio (SNR) improvement factor similar to that of FM with considerably less sacrifice of spectral occupancy. Several signal-space mappings are investigated for Gaussian data. Expressions for output SNR are derived in terms of a linear error above threshold and an anomalous threshold-producing error. PAPM is compared with various modulation techniques in terms of power and bandwidth requirements. The degradations in output SNR caused by carrier phase, carrier amplitude, and sample timing reference errors are evaluated so that requirements for demodulator design can be specified.

Keywords

PAM communication; PM communication; Amplitude modulation; Bandwidth; Data communication; Demodulation; Frequency modulation; Pulse modulation; Satellites; Signal mapping; Signal to noise ratio; Telephony;

fLanguage

English

Journal_Title

Communications, IEEE Transactions on

Publisher

ieee

ISSN

0090-6778

Type

jour

DOI

10.1109/TCOM.1975.1092849

Filename

1092849