13.07.2015 Views

View File - University of Engineering and Technology, Taxila

View File - University of Engineering and Technology, Taxila

View File - University of Engineering and Technology, Taxila

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

stable over their operating temperature range to maintain the desired rejectioncharacteristics. The functionality <strong>of</strong> these devices (each component block inFig. 2.2), is addressed later in this chapter. A transponder may channel thesatellite capacity both in frequency <strong>and</strong> in power <strong>and</strong> may be accessed by oneor several carriers.In most system applications, one satellite serves many earth stations.With the assistance <strong>of</strong> earth stations, fixed or transportable, satellites areopening a new era for global satellite multiaccess channels’ data transmission<strong>and</strong> broadcast <strong>of</strong> major news events, live, from anywhere in the world.Commercial <strong>and</strong> operational needs dictate the design <strong>and</strong> complexity <strong>of</strong>satellites. The most common expected satellite attributes include the following:1. Improved coverage areas <strong>and</strong> quality services, <strong>and</strong> frequencyreuseability2. Compatibility <strong>of</strong> satellite system with other systems <strong>and</strong> exp<strong>and</strong>ability<strong>of</strong> current system that enhances future operations3. High-gain, multiple hopping beam antenna systems that permitsmaller-aperture earth stations4. Increased capacity requirements that allow several G=sec communicationbetween users5. Competitive pricingFIGURE 2.2Basic transponder arrangement.Copyright © 2002 by Marcel Dekker, Inc. All Rights Reserved.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!