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:
May. 15, 2007
Filed:
Mar. 13, 2003
Teruji Ide, Tokyo, JP;
Kazuo Akaike, Hamura, JP;
Kazushi Takahashi, Tokyo, JP;
Manabu Nakamura, Tokyo, JP;
Teruji Ide, Tokyo, JP;
Kazuo Akaike, Hamura, JP;
Kazushi Takahashi, Tokyo, JP;
Manabu Nakamura, Tokyo, JP;
Hitachi Kokusai Electric Inc., Tokyo, JP;
Abstract
To solve such a problem of a conventional direct conversion receiver that an image rejection ratio is insufficient owing to analog processing employed to reject an image, the present invention provides such a direct conversion receiver that the image can be rejected by digital signal processing to improve the image rejection ratio and also reduce the hardware load and the processing load. A HILBERT filter of a digital signal processing section shifts a quadrature component digital signal by 90° by HILBERT conversion to provide an output, while a delay circuit delays an in-phase component digital signal by the same delay time as a delay time by the HILBERT filter to provide an output, both of which outputs undergo addition or subtraction at an adder to have the image rejected there and then enter a complex frequency converter, where an offset provided at a local oscillator is removed by frequency conversion processing to output the in-phase component and quadrature component signals.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile