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:
Jan. 16, 2007
Filed:
Dec. 24, 2003
Yuanjin Zheng, Singapore, SG;
Chin Boon Tear, Singapore, SG;
Sheng Jau Wong, Johor Bahru, MY;
Agency for Science, Technology and Research, Singapore, SG;
Abstract
A DCR RF front-end removes the DC term resulting from mixer port to port leakage and feeds RF and LO signals into the mixers with different phase combinations. The signal inputs to the mixers result in the intermediate frequency (IF) output of mixers being 180 degrees out of phase and their DC terms in phase. When subtracting the two outputs from each other the IF signals add up while the DC terms cancel giving a DC free output. A DC offset feedback tuning loop detects the DC offset in the IF domain and then feeds back the tuning voltage to current injection mixers. A multiplier cancels the IF signals and amplifies the DC offset and a comparator compares the amplified DC offset with a threshold voltage and controls the gain of current injection mixers. The feedback tuning loop thus tracks time-varying DC offsets in real-time.