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:
Sep. 19, 2000
Filed:
Feb. 27, 1998
Kenji Yoshioka, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
When the frequency band of an intermediate frequency (IF) signal input to a filter rises due to temperature variation, the center voltage corresponding to the IF signal also rises. As a result, a difference occurs between the center voltage and a preselected reference voltage. An output current produced by converting the difference is so output as to increase a control current, thereby shifting the frequency characteristic of the filter to the higher frequency side. When the frequency band of the IF signal falls due to temperature variation, the center voltage also falls. The resulting difference between the center voltage and the reference voltage is also transformed to an output current. This output current is so output as to reduce the control current with the result that the frequency characteristic of the filter is shifted to the lower frequency side.