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:
Feb. 04, 2003
Filed:
Sep. 22, 1999
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
In an image-rejection receiver having a first frequency conversion stage ( ) having a pair of frequency mixers ( ) each supplied external radio frequency signal (RF) and first local frequency signal (LOCAL ) with quadrature phase relations ( ), a second frequency conversion stage ( ) having two pairs of frequency mixers ( ) at each output of each first stage mixer and second local frequency signal (LOCAL ) with quadrature phase relations ( ), and an adder ( ) and a subtractor ( ) for providing sum and difference of amplitude of outputs of said second frequency conversion stage to provide inphase component (BBI) and quadrature-phase component (BBQ), no filter is used for removing an undesirable image signal which is generated in frequency conversion. A control circuit ( ) is provided to keep accurate quadrature phase relations for said first local frequency signal, and said second local frequency signal, by measuring D.C. component of a product of outputs of two of mixers.