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. 25, 2011
Filed:
Nov. 12, 2009
Hiroki Kimura, Chitose, JP;
Hiroki Kimura, Chitose, JP;
Nihon Dempa Kogyo Co., Ltd, Tokyo, JP;
Abstract
To provide a highly stable oscillation frequency control circuit wherein the frequency thereof is corrected, an adequate range of the input levels of external reference signals is determined in accordance with temperature characteristics in detecting the external reference signal, and the control voltage to a VCO is controlled within and outside the adequate range. An oscillation frequency control circuit includes a selection switch that connects the phase comparator to the loop filter in an external reference synchronization mode and that connects the fixed voltage supplying circuit to the loop filter in a fixed voltage mode, and a CPU that switches the selection switch to the external reference synchronization mode or to the fixed voltage mode based on whether the detected voltage of an external reference signal level is within or outside of the adequate range.