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:
Aug. 17, 1976
Filed:
May. 19, 1975
Bruce G Erickson, Santa Clara, CA (US);
American Micro-Systems, Inc., Santa Clara, CA (US);
Abstract
Apparatus for ascertaining that the resonant frequency of a crystal frequency determining element lies within a predetermined frequency range is disclosed. A crystal whose frequency is to be measured is connected to an oscillator which provides vertical and horizontal deflection signals to a cathode ray tube device. Two crystal controlled signal generators provide series of short duration output impulses which are applied to the control grid of the cathode ray tube. One oscillator operates at the upper frequency limit of the frequency range, and the other oscillator operates at the lower frequency limit. If the crystal undergoing tests lies between the two frequencies of the two reference generators, two spots appearing on the screen of the cathode ray tube will rotate countercurrent with one another. If the frequency of the crystal undergoing test lies outside of the frequency range fixed by the two signal generators, those spots will rotate in the same direction, either clockwise or counterclockwise, depending upon whether the frequency of the crystal lies above or below the desired range.