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. 26, 1983
Filed:
Feb. 23, 1981
Donald H Steinbrecher, Carlisle, MA (US);
Steinbrecher Corporation, Woburn, MA (US);
Abstract
A method and apparatus for monitoring the resonant frequency and absorption level at resonance of an absorption type resonant cavity which involves providing a voltage controlled oscillator, applying to the control input of the voltage controlled oscillator a control signal having a main component V.sub.m and a dither component V.sub.d, splitting the output signal from the voltage controlled oscillator into a portion directed along a test path and a portion directed along a reference path, the reference path including an attenuator controlled by a voltage signal V.sub.k, directing the signal in the test path through the resonant cavity, splitting the signal emerging from the resonant cavity into a portion directed along a frequency detection path and a portion directed along a level detecting path, using the signal directed along the frequency detection path for generating a signal for changing the amplitude of V.sub.m until the center frequency of the output signal of the voltage controlled oscillator is at the resonant frequency f.sub.r of the cavity, and using the signal directed along the level detection path for changing V.sub.k until the level of the signal in the reference path is equal to the depth of the null of the signal in the level detection path.