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:
Nov. 22, 2005
Filed:
Mar. 27, 2002
Hizuru Nawata, Tokyo, JP;
Hizuru Nawata, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A satellite communication transmission control system includes one central station, a plurality of small aperture terminals, and one communication satellite serving as a repeater for the central and aperture terminals. This system performs communication via a frequency division multiple access communication channel. The central station includes a modulator for transmitting via a common channel a signal for controlling/monitoring the small aperture terminals on the basis of a stable clock signal. Each aperture terminal includes a modulator, transmission frequency converter, antenna/RF device, reception frequency converter, demodulator, and frequency comparator. The modulator modulates communication information. The transmission frequency converter frequency-converts a modulated wave from the modulator into a carrier signal (modulated carrier). The reception frequency converter frequency-converts the modulated carrier. The demodulator demodulates a signal received via the common channel and outputs a reception clock. The frequency comparator detects the frequency error of a local oscillator, and generates a control signal for stopping transmission of the modulated carrier until the frequency error falls within a preset tolerance range.