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. 17, 2012
Filed:
Mar. 03, 2009
Kenji Toyota, Tokyo, JP;
Kazuhiko Hikasa, Tokyo, JP;
Kenji Toyota, Tokyo, JP;
Kazuhiko Hikasa, Tokyo, JP;
Renesas Electronics Corporation, Kanagawa, JP;
Abstract
A transmitter has a transmission modulator including first and second modulators, a phase comparator and a controller. First and second non-inverted local signals supplied to the modulators are set to have a predetermined phase difference. In a calibration action for reducing carrier leakage, the phase comparator is supplied with the first or second local signals, and carrier signals leaking at an output of the transmission modulator. The controller keeps changing the ratio of DC biasing currents to paired transistors of each modulator until the predetermined phase difference is detected with the phase comparator. When the predetermined phase difference is detected, the controller stops changing the ratio of DC biasing currents. The chip footprint of a transmitter on the direct up-conversion (DUC) architecture is reduced, and carrier leakage owing to local signals supplied to the transmission modulator are decreased.