A Transition Density Analyzer for High Density Digital Codes

Abstract

A portable test instrument useful in optimizing the performance of high density digital recorders is described in this paper. The instrument, a transition density analyzer, provides a graphic display of the distribution of transitions with respect to time for a variety of PCM digital data formats. The concept of a transition density analyzer as an improvement upon eye pattern assessment techniques was presented at the 1976 International Telemetering Conference by Mr. J. P. Lerma of Odetics, Inc., Anaheim, California. Mr. Lerma's paper emphasized the mathematical modeling of probability density functions and the synthesis of these models by a density analyzer. Mr. Lerma's concept has since been reduced to a working prototype which is currently under evaluation at Odetics. Discussed in this paper are the operational characteristics of the instrument as well as applications and the results of its usage on some high density digital recorders.