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:
Sep. 21, 1976
Filed:
May. 06, 1974
Albert E Sanderson, Carlisle, MA (US);
Inventronics, Inc., Carlisle, MA (US);
Abstract
A phase difference detector and display unit. A digital pulse train at the frequency to be measured is combined with a multiple-phase digital clock output having a reference frequency to produce multiple-phase signals which low-pass filters convert to dc output signals. Each output signal indicates the instantaneous phase difference between the digital pulse train and a respective one of the clocking signals. Each dc output signal controls the light from a pair of lamps. Individual lamps in each pair are diametrically opposed on a circle with all the pairs being spaced around the circumference of the circle. The lamp pairs reach maximum brightness in sequence, providing the illusion of a rotating light bar. The direction of rotation indicates whether the digital pulse train is higher or lower in frequency than the reference while the speed of rotation is proportional to the frequency deviation from the reference.