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. 15, 1994
Filed:
Oct. 06, 1992
Satoshi Denno, Kanagawa, JP;
Yoichi Saito, Kanagawa, JP;
Nippon Telegraph and Telephone Corporation, Tokyo, JP;
Abstract
A method and an apparatus for demodulation with adaptive phase control in quasi-coherent detection, capable of compensating detection phase error due to the initial phase error and the frequency error at high speed and high quality, without a complicated circuit configuration and a significant delay. In the apparatus, a frequency error in the modulated complex input signals is estimated by using a phase variation during one symbol due to the frequency error according to the modulated complex input signals and the demodulated complex signals for present and immediately previous symbols; an initial phase error in the modulated complex input signals is estimated according to the modulated complex input signals, the demodulated complex signals, and the estimated frequency error; and the demodulated complex signals are obtained by applying optimum phase compensation determined according to the estimated frequency error and the estimated initial phase error, to the modulated complex input signals.