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:
Dec. 22, 1987
Filed:
May. 02, 1986
Tatsuro Masamura, Tokyo, JP;
Canadian Patents And Development Limited, Ottawa, CA;
Abstract
A diversity receiving system for differential detection of minimum shift key (MSK) signals. The system may be advantageously implemented in order to realize high quality mobile satellite communication systems where shadowing is a significant problem and channel bandwidth and power are constrained. Signals from each of a plurality of receiving branches are translated to different intermediate frequencies which differ from each other by multiples of the transmitted signal symbol rate. The intermediate frequency signals are summed and detected via a common differential detector, the latter being followed by a low pass filter having a bandwidth corresponding to a fraction of the symbol rate. The plural signals are easily and stabely combined at an intermediate frequency stage without phase adjusters, signal quality measurement circuits or switching controllers. Moreover, the error rate performance is equivalent to that of post detection equal gain combining diversity schemes, which require plural complete receiving systems.