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:
Sep. 16, 2003
Filed:
May. 21, 1999
Joseph W. Niesen, La Mirada, CA (US);
Northrop Grumman Corporation, Los Angeles, CA (US);
Abstract
A digital Intermediate Frequency (IF) QAM receiver is provided which yields an improved SNR. The digital IF QAM receiver eliminates the integration step ( ) and low pass filters ( ) of a standard digital QAM receiver Instead, the digital IF QAM receiver mixes the received signal with a an intermediate frequency (IF) local oscillator (LO) After mixing with the IF LO each channel is band pass filtered ( ), and then converted from analog to a digital signal ( ). The digital signal is then demultiplexed ( ) into a plurality of streams of digital pulses. The stream with the maximum average power is then selected by a select stream processor ( ). The selected stream is time aligned to conform to a symbol period by a stream timing alignment processor ( ). The aligned stream for both the I and Q channels is sent to a maximum likelihood decision mapping processor which determines the respective bit code.