Engineering topics

Carden, Frank

Publications and source records attributed to Carden, Frank.

2 records

NASA NTRS1992

Multi-mode modem/codec designs

The design of an integrated modem/codec unit which can receive coded and uncoded BPSK an QPSK using de facto standard coding schemes as well as 8PSK-TCM and 16PSK-TCM is examined. The design is totally compatible with today's modulation schemes and capable of processing tomorrow's TCM codes. This is accomplished in the modem by using quadrature channel carrier recovery processing and a version of the MAP phase detector algorithm. The symbol synchronization is accomplished with a derivative of an early-late gate designed to accommodate multilevel signals.

Osborne, William↗

NASA NTRS1991

64-state TCM for spectrally efficient space communications

Rate 2/3 8-PSK codes of 4, 8, 16, and 64 states were tested by simulation. The codes used are those found in Ungerboeck's original search. The results found were in close agreement with those predicted by analytical means in current literature. The Ungerboeck codes of 8, 16, and 64 states show coding gains of 0.2, 0.3, and 0.86 dB, respectively, relative to the four state code. In general, worthwhile gains are obtained in increasing the number of states of the encoder up through 64.

Carden, Frank↗