Snelsire, R. W. | Search NASA

NASA NTRS1974

Evaluation of three coding schemes designed for improved data communication

Three coding schemes designed for improved data communication are evaluated. Four block codes are evaluated relative to a quality function, which is a function of both the amount of data rejected and the error rate. The Viterbi maximum likelihood decoding algorithm as a decoding procedure is reviewed. This evaluation is obtained by simulating the system on a digital computer. Short constraint length rate 1/2 quick-look codes are studied, and their performance is compared to general nonsystematic codes.

Snelsire, R. W.↗

NASA NTRS1972

Evaluation of minimum variance estimators for signal derivatives in real noise environments

A digital filter has been developed to optimally estimate the rate of descent of an aircraft to permit all-weather operation. The filter was evaluated using recorded rate of descent information from flight instruments. The evaluation showed the filter to be superior to other systems especially when operated in turbulent air.

Snelsire, R. W.↗