A report discusses the performance of a soft digital-data-transition tracking loop (DTTL) in a radio receiver that recovers digital data conveyed by binary phase-shift keying. The DTTL is used as a symbol synchronizer; it provides symbol timing to essential parts of the receiver. The DTTL includes a quadrature channel and an in-phase channel, which contains a transition detector with a hyperbolic-tangent response. The DTTL is said to be "hard" or "soft" in the special case of high or low signal-to-noise ratio (high or low SNR, respectively), for which the hyperbolic tangent can be approximated as a hard-limiting or a linear function, respectively.

This work was done by Samson Million and Sami Hinedi of Caltech for NASA's Jet Propulsion Laboratory. NPO-20154

This Brief includes a Technical Support Package (TSP).
Performance of a soft digital-data-transition tracking loop

(reference NPO20154) is currently available for download from the TSP library.

Don't have an account? Sign up here.

NASA Tech Briefs Magazine

This article first appeared in the June, 1998 issue of NASA Tech Briefs Magazine.

Read more articles from the archives here.