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. 01, 2001
Filed:
Jan. 13, 1999
Hiroki Tsuda, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
In a mobile satellite communications system comprising an earth station (,), a mobile station (,) with a mobile antenna (,), and a communication satellite (,) for mediating communications between the earth station and the mobile station, the earth station comprises a carrier frequency variation detecting device (,) for detecting a received carrier frequency due to a doppler effect to produce a frequency variation detected signal. Although an earth signal processing circuit (,) transmits a burst carrier signal or a maintaining burst signal to the mobile station when an information signal such as a speech signal to be transmitted is not supplied thereto, the earth signal processing circuit extends a burst transmission duration for the maintaining burst signal in response to the frequency variation detected signal and it results in making the mobile station easily carry out antenna tracking control. In addition, the earth signal processing circuit continuously transmits the carrier signal when a received frame synchronization is pulled out.