ABSTRACT
Satellite crosslinks generally require narrower bandwidths for increased power concentration. We can increase the power concentration by increasing the cross page link frequency with the same size antenna. But the source technology and the modulation hardware required at these higher frequency bands are still in the development stage. Use of optical frequencies will help to overcome this problem with the availability of feasible light sources and the existence of eff ....etc

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Basic of Communication




A radio communication system send signals by radio
Types of radio communication systems deployed depend on technology, standards, regulations, radio spectrum allocation, user requirements, service positioning, and investment.
The radio equipment involved in communication systems includes a transmitter and a receiver, each having an antenna and appropriate terminal equipment such as a microphone at the transmitter and a loudspeaker at the reciever in the case of a voice-communication sy ....etc

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Introduction

-communications system
is a collection of individual communications networks, transmission systems, relay stations, tributary stations, and data terminal equipment (DTE) usually capable of interconnection and interoperation to form an integrated whole.
....etc

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CHAPTER 1
INTRODUCTION

Communication links between space crafts is an important element of space infrastructure, particularly where such links allow a major reduction in the number of earth stations needed to service the system. An example of an inter orbit page link for relaying data from LEO space craft to ground is shown in the figure below



Interorbit page link for relating data from LEO spacecraft to ground

Fig. 1
Inter orbit page link for relaying data from LEO space craft to ground.


The above figure represents a ....etc

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BASIC INSTRUMENTATION MEASURING DEVICES AND BASIC PID CONTROL


INTRODUCTION
Instrumentation is the art of measuring the value of some plant parameter,
pressure, flow, level or temperature to name a few and supplying a signal
that is proportional to the measured parameter. The output signals are
standard signal and can then be processed by other equipment to provide
indication, alarms or automatic control. There are a number of standard
signals; however, t ....etc

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The beginning of new millenium sees an important milestone in military aviation communication with the introduction of the first Super-High-Frequency (SHF) airborne satellite communication (Satcom) terminals, which are due to enter service on Nimrod maritime reconnaissance aircraft (MRA4). Satcom terminals using the Ultra-High-Frequency (UHF) band have been fitted to larger aircrafts for a number of years. Although relatively simple to install and comparatively inexpensive, UHF satcoms(240-270 & 290-320 MHz bands) suffers from very limited capa ....etc

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ABSTRACT
This paper outlines some of the techniques being developed to provide affordable, reliable satellite communications suitable for a wide range of military aircraft, from agile platforms such as jets and helicopters to surveillance, tanker and transport aircraft. It also gives an overview of airborne SHF (Super High Frequency) and also EHF (Extremely High Frequency) satcom techniques. Although presently used UHF (Ultra High Frequency) satellite communication are relatively simple to install and comparatively inexpensive, suffer from ....etc

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Definition

The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.

The SILEX GEO terminal is capable of receiving data modulated on to ....etc

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Definition

The European Space Agency (ESA) has programmes underway to place Satellites carrying optical terminals in GEO orbit within the next decade. The first is the ARTEMIS technology demonstration satellite which carries both microwave and SILEX (Semiconductor Laser Intro satellite Link Experiment) optical interorbit communications terminal. SILEX employs direct detection and GaAIAs diode laser technology; the optical antenna is a 25cm diameter reflecting telescope.

The SILEX GEO terminal is capable of receiving data modulated on to ....etc

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Abstract
LEO is Low Earth Orbit satellite.It circulates on a lower orbit in a shorter period . Additionally LEO systems try to ensure a high elevation for every spot of the earth to provide a highquality communication page link . The networks will play an important role in the evolving information infrastructure . It provides communication with shorter endto- end delays and e_ciency frequency usages . Some problems need to be solved before LEO satellite system can be successfully deployed . One of these problems is handover management . Even ....etc

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