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:
Mar. 08, 1977
Filed:
Oct. 16, 1975
John M Ferrara, Yardley, PA (US);
Narco Scientific Industries, Inc., Fort Washington, PA (US);
Abstract
A known reference signal is applied to a zero crossing detector and normal and inverted outputs from the zero crossing detector are applied to the input control terminals of a pair of bilateral switches. A measured signal of the same frequency but not necessarily of the same phase is simultaneously applied to the input terminals of the bilateral switches. The resultant output of the bilateral switches is connected to a parallel RC network. The capacitor acquires a charge proportional to the deviation from 90.degree., which is applied to a differential amplifier. The output of the differential amplifier is used to drive a meter which indicates the phase relationship of the two signals. The capacitor used to accumulate the net charge is ungrounded to eliminate errors resulting from unequal currents to ground.