Integrated Circuit Correlator for Flow Measurement

Abstract

A polarity correlator is described having a novel output stage which only makes available the output states of the integrating counters monitoring coincidences between upstream and downstream input signals. The evolving pattern of overloads corresponding to the time delay increment range of the correlator completely describes the polarity correlation function. In particular, the pattern corresponding to the peak of the function gives the time delay position of the peak. The reciprocal of the peak position is proportional to flow velocity when the input signals are derived from flow noise generated at two points along a flow stream. A special purpose LSI circuit has been produced for the low cost realisation of this system.