Definition
Multi Carrier Modulation is a technique for data transmission by dividing a high ?]bit rate data stream is several parallel low bit ]rate data streams and using these low bit rate data streams to modulate several carriers. Multi Carrier Transmission has a lot of useful properties such as delay spread tolerance and spectrum efficiency that encourage their use in untethered broadband communications. OFDM is a multi carrier modulation technique with densely spaced sub carriers that has gained a lot of popularity among the broadband com ....etc

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Real Time Operating Systems for Networked Embedded Systems


Fire Alarm System

Problem
Hundreds of sensors, each fitted with Low Range Wireless
Sensor information to be logged in a server & appropriate action initiated
Possible Solution
Collaborative Action
Routing
Dynamic – Sensors/controllers may go down
Auto Configurable – No/easy human intervention.
Less Collision/Link Clogging
Less no of intermediate nodes
Fast Response Time
Secure

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Introduction
Reducing interference in a cellular system is the most effective approach to increasing radio capacity and transmission data rate in the wireless environment. Therefore, reducing interference is a difficult and important challenge in wireless communications.

In every two-way communication system it is necessary to use separate channels to transmit information in each direction. This is called duplexing. Currently there exist only two duplexing technologies in wireless communications, Frequency division duplexing (FDD) and time ....etc

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In a WDM system, each of the wavelengths is launched into the fiber, and the signals are demultiplexed at the receiving end. Like TDM, the resulting capacity is an aggregate of the input signals, but WDM carries each input signal independently of the others. This means that each channel has its own dedicated bandwidth; all signals arrive at the same time, rather than being broken up and carried in time slots. The difference between WDM and dense wavelength division multiplexing (DWDM) is fundamentally than does WDM, and therefore has a greater ....etc

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ABSTRACT

This paper presents a new design and implementation of HDD (Hard Disk Drive) embedded DSR (Digital Satellite Receiver). The digital broadcasting technology enables multimedia access via broadcasting system. The amount of digital data to be processed is increased as compared to the previous broadcasting environment. In this paperâ„¢ a method is proposed to provide storage ability of a DSR to cope with these changes. Efficient digital data storage and management technology is also discussed. The real data recording and playing b ....etc

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This paper deals with the twin concepts of optical networking and dense wavelength division multiplexing. The paper talks about the various optical network architectures and the various components of an all-optical network like Optical Amplifiers, Optical Add/Drop Multiplexers, Optical Splitters etc. Important optical networking concepts like wavelength routing and wavelength conversion are explained in detail. Finally this paper deals with industry related issues like the gap between research and the industry, current and projected market for ....etc

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Frequency Division Multiple Access Used for AMPS and TACS, the two key analog systems and their variants, this system gives each conversation its own unique radio channel. Division of a radio frequency into several channels by splitting the frequency band into distinct segments, which are assigned to various callers. This allows a single base station to serve many callers. For example, a typical AMPS network will have 832 channels spaced approximately 30 kilohertz apart. - Frequency Division Multiple Access, digital transmission technology that ....etc

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SUBMITTED BY
Trupty Acharya


ABSTRACT
This is the era of revolutions in electronics design and it has been improving by the continuous advancement in the technology and computer science in the last three decades. The electronics industries are growing rapidly due to the development in integrated circuits (ICs). Although the use of high performance computing, telecommunication devices, computers are increasing rapidly, they are not easily portable. This age is for portable gadgets which serve all types of comm ....etc

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TDMA, or Time Division Multiple Access was one of the first cell phone digital standards available in the United States. It was the first successor to the original AMPS analog service that was popular throughout the country, and was in popular service from the early-mid 1990's up until roughly 2003 when the last of the TDMA carriers, Cingular and AT&T, switched to the GSM digital standard.

TDMA was a significant leap over the analog wireless service that was in place at the time, and it's chief benefit for carriers was that it used the avail ....etc

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