Digital displacement transducer using pseudo-random binary sequences and a microprocessor

Abstract

This novel transducer enables measurement of displacement over a large range without undue expense to be made; high resolution is possible. A maximal length pseudo-random binary sequence is laid down as a mechanical track of 1s and 0s. As the moving component traverses the track in a given direction it causes the sequence to be inputted into a microcomputer in which it is compared with a similar sequence generated internally. When the two patterns become identical, then the absolute position of the moving component is defined with a digital output. A second digital track is required for bidirectional displacement. Various transducer configurations are proposed.