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:
Oct. 27, 1981
Filed:
Oct. 15, 1979
Shuzo Fujii, Tokyo, JP;
Yoshikatsu Sato, Tokyo, JP;
Nippon Electric Co., Ltd., Tokyo, JP;
Abstract
A temperature compensated crystal oscillator having a crystal resonator uses a single thermistor and no expensive varactor. The compensation circuit includes, a low temperature compensation circuit consisting of a first fixed capacitor and a first diode in series, a high temperature compensation circuit consisting of a second fixed capacitor and a second diode in series, and an intermediate temperature compensating circuit consisting of a third capacitor having a negative temperature coefficient. All three circuits are in parallel with each other and in series with the crystal resonator of the oscillator. A thermistor is connected to the anodes of both diodes and biasing resistors and connected to the cathode of the second diode whereby a temperature dependent forward bias is applied to the first diode at all temperatures and to the second diode only at the high temperatures.