Phase Distortion Study (Phase B)
Abstract
This is the Final Report of a 6 month study of duobinary digital data transmission over the DSCS. Analysis and computer simulations were developed for evaluating the degradation for duobinary SQPSK in the FDMA and TDMA modes, with emphasis on maximizing the bandwidth utilization capability of duobinary signalling. In a linear channel, single-access duobinary achieves rates of 3 bps/Hz, decreasing to 2.5 bps/Hz with a saturating transmitter and satellite. For duobinary FDMA, rates to 2.67 bps/Hz are possible in a nonsaturating channel with rates to 2.2 bps/Hz in a saturating channel. Error correction coding of duobinary is not recommended. Duobinary modem considerations and implementations are discussed in depth. The modem should incorporate phase distortionless maximally-flat filters, a sampling detector, 4-bit quantizer, the Viterbi algorithm, modified sync and phase tracking loops, and (preferably) an adaptive equalizer. While a new modem design is recommended, modification of the Harris MD-1002 modem for duobinary SQPSK operation is possible, and the required changes are specified in detail. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1977
- Accession Number
- ADA063779
Entities
People
- C. L. May
- C. R. Cahn