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:
Dec. 23, 1986
Filed:
Apr. 25, 1985
Gary W Sherwin, South Huntingdon Township, Westmoreland County, PA (US);
Westinghouse Electric Corp., Pittsburgh, PA (US);
Abstract
A phase locked loop stepper motor controlled light chopper for providing a specific pattern reversal rate. The stepper motor controlled light chopper includes a phase comparator for comparing the phase of a reference signal to the phase of a comparison signal; a RC low pass filter for filtering the output of the phase comparator; a voltage controlled oscillator having a frequency varying in response to the output of the RC filter. The chopper also includes a binary counter for generating count signals responsive to the frequency of the voltage controlled oscillator; a divide by 10 circuit counting one of the outputs of the binary counter and providing the comparison signal. The light chopper also includes a memory circuit for storing an eight state four bit gray code for driving a four phase stepper motor as a chopper wheel in a specified pattern mounted on a drive shaft.