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:
Jul. 05, 2005
Filed:
Sep. 06, 2002
Dominique Python, Sunnyvale, CA (US);
Pierre Favrat, Sunnyvale, CA (US);
Didier Margairaz, Saratoga, CA (US);
Alain-serge Porret, Sunnyvale, CA (US);
Dominique Python, Sunnyvale, CA (US);
Pierre Favrat, Sunnyvale, CA (US);
Didier Margairaz, Saratoga, CA (US);
Alain-Serge Porret, Sunnyvale, CA (US);
Xceive Corporation, Santa Clara, CA (US);
Abstract
A tunable filter circuit includes a first differential pair biased by a first current, a second differential pair biased by a second current, a first capacitor and a second capacitor. The tunable filter circuit of the present invention can be configured as a bandpass filter or a bandstop filter by connecting the input voltage signal to different input nodes of the tunable filter circuit. The tunable filter circuit can be tuned by adjusting the values of the first current and the second current. In an alternate embodiment, frequency tuning is achieved either by switching capacitive loads or changing resistive impedances introduced at the emitter of the differential pairs, which also extends the input voltage range of the filter. This emitter resistance is implemented using MOS switches whose on-resistance can be controlled for a precise tuning within a large frequency range.