The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 22, 1986
Filed:
Jun. 27, 1983
Robert C Moore, Rochester, NY (US);
GCA Corporation, Bedford, MA (US);
Abstract
Analog-to-digital conversion and a computer produce finer resolution for interferometer distance measurement. The system applies to a laser interferometer producing two detected signals with voltages 19 and 20 that vary to form two sine waves in quadrature as interference fringes occur. A pair of analog-to-digital converters 21 and 22 converts each of these signals into digital values subdividing each sine wave fringe cycle into a plurality of increments. An up/down counter 25 supplied with a significant digit from each of the converters counts fringes corresponding to changes in path lengths. A computer 30 arranged with access to the fringe count and the digital increments determines a distance measurement based on the fringe count and a fine resolution of the distance measurement based on final values of the signals at any subdivided fringe cycle increments after changes in the path lengths.