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:
Dec. 29, 2009
Filed:
Jan. 28, 2005
Satoshi Niwa, Tokyo, JP;
Kazuo Ogoro, Tokyo, JP;
Satoshi Niwa, Tokyo, JP;
Kazuo Ogoro, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
Disclosed are an apparatus and a method for the adjustment time for IQ offset of a quadrature modulator of a transmission circuit. In adjusting the I-offset and the Q-offset of a quadrature modulator, supplied with an I-signal and a Q-signal output from an analog baseband unit to modulate a carrier. Set-up values of the I-offset and the Q-offset, associated with at least three different points on an IQ offset correction plane having an I-component and a Q-component as X- and Y-coordinates, are set for the analog baseband unit at respective different set-up timings. The values of the carrier leak level, associated with three-point offset set-up values of the output signal of the quadrature modulator, are acquired by a sole measurement operation. From the measured values of the three-point carrier leak levels, the values of the carrier suppression ratio for the three points are found from the measured values of the three points of the carrier leak level to find the optimum set-up values of the I-offset and the Q-offset.