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. 10, 1994
Filed:
Jun. 17, 1991
Applicant:
Inventor:
David N Critchlow, San Diego, CA (US);
Assignee:
Hughes Aircraft Company, Los Angeles, CA (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03H / ;
U.S. Cl.
CPC ...
375 14 ; 375 80 ; 375 86 ; 375 96 ; 375 97 ; 329304 ;
Abstract
A receiver designed for use in a mobile environment, which includes an adaptive equalizer driven by phase estimation and rotation circuitry, and which is operable in multipath fading channels. The present invention uses an AFC loop and a phase rotation circuit in front of the adaptive equalizer to improve equalizer performance in the fading channel. The present invention uses .pi./4 phase rotation circuitry before a phase quantization decision is made. This .pi./4 phase rotation circuitry allows for decisions to be made on a QPSK constellation, rather than on an input 8PSK constellation, thus improving detection performance.