Linear Modulation Techniques for Digital Microwave
Abstract
The objective of this program was to study and develop modulation techniques and implementation methods applicable to a linear digital microwave radio operating in the 4 and 8 GHz frequency bands. Modulation techniques capable of providing 3 to 4.5 bits/sec/Hz under the FCC Docket 19311 spectral criterion are developed and included herein. Techniques for the practical implementation of spectrally efficient linear modulation (AM-PM) signal designs in conjunction with presently available microwave power amplifiers are developed. An adaptive predistortion technique for linearizing nonlinear power amplifiers (e.g., TWT's) for the purpose of counteracting AM/AM and AM/PM conversion effects is presented which is useful for linear digital signal designs. A new baseband adaptive equalization scheme which is suited to high rate digital modems is presented. M-ary Quadrature Amplitude Modulation (M-QAM) is chosen as the most efficient scheme for obtaining 3 to 5 bits/sec/Hz under FCC Docket 19311. Waveguide filtering is used to provide FCC Docket 19311 compliance with the M-QAM schemes. An error correction coding/decoding strategy which is applicable to M-QAM signal formats is presented. On the theoretical side, techniques for determining spectral and prformance properties for constrained bandwidth digital signaling are discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1979
- Accession Number
- ADA074047
Entities
People
- Robert C. Davis
Organizations
- Harris Corporation