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. 28, 1991
Filed:
Jan. 10, 1989
Yasuhito Isoe, Tokyo, JP;
NEC Corporation, , JP;
Abstract
In a satellite communications system, satellite channels are divided into groups of successively adjacent channels which are covered by a range of frequency drifts caused by a satellite transponder and the channels of each group are assigned unique words of different bit patterns. Modulation systems of an earth station are associated respectively with demodulation systems of distant earth station via the respective satellite channels. A unique word is transmitted from each modulation system together with an information signal and received by an associated demodulation system of the distant earth station. A variable frequency carrier is synthesized in the demodulation system to demodulate the received signal to recover the information signal and the unique word. The recovered unique word is used to establish the frame start timing and the variable frequency carrier is controlled in response to the unique word to tune in the demodulation system to the desired satellite channel.