Multiple access (MA) schemes are used to simultaneously share available bandwidth in communication systems. In conventional MA applications a finite and contiguous amount of spectrum which is designated for a particular service is allocated to multiple users. Therefore, the use of designated radio spectrum is unconstrained and can be utilized in many ways to achieve maximum efficiency. Time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA) are the three major MA techniques. In ....etc

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A High Data Rate Frequency Hopping Modulation Scheme
Theme:ECE/Digital Communications

Submited By:
Hemanth Patnala
R.V.Seshu Kumar
Sir C.R.R. College Of Engineering,
Eluru-534002
ABSTRACT
There is a need to select the 'first step up' modulation scheme for higher data rate frequency hopping systems. This is seen as one step in a longer journey where considerably higher data rates are used. In order to make this progression viable, the first step should be taken with a well proven modulation scheme. An ....etc

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A Technique for Orthogonal Frequency Division Multiplexing
Frequency Offset Correction

Abstract:
The Orthogonal Frequency Division Multiplexing (OFDM) is a Multi Carrier Modulation technique employing Frequency Division Multiplexing of orthogonal subcarriers. It is also sometimes called as discrete multitone modulation (DMT). It is better than CDMA in high bit rate and Broadband Communications .It is a multi carrier technique, which is very sensitive to Frequency Offset between transmitter and receiver. Th ....etc

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Definition

RF light sources follow the same principles of converting electrical power into visible radiation as conventional gas discharge lamps. The fundamental difference between RF lamps and conventional lamps is that RF lamps operate without electrodes .the presence of electrodes in conventional florescent and High Intensity Discharge lamps has put many restrictions on lamp design and performance and is a major factor limiting lamp life.

Recent progress in semiconductor power switching electronics, which is revolutionizing many facto ....etc

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A Surveillance Robot with Hopping Capabilities for Home Security


Abstract —
Most traditional home robots have always had problems with stairs, doorsills and other
obstacles that humans cross with ease in cluttered indoor environments. This paper
presents the development and characterization of a surveillance robot with hopping
capabilities for home security. The proposed robot can leap over obstacles. It can also roll
freely on flat floors and change its directions by the two-wheeled differential drive
system. It adop ....etc

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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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Power frequency magnetic fields as high as 15,000,000 milligauss are commonly found internally in equipment such as power transformers, motors and generators .Although these fields are almost contained within the equipment ,some leakage will occur. This paper concentrates on magnetic fields in the range of zero to several hundred milligauss. This level of magnetic field may be experienced by the general public as a result of operation of electrical equipment, current carrying lines, house wiring, electrical appliances, lighting equipment or an ....etc

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Multiple access (MA) schemes are used to simultaneously share available bandwidth in communication systems. In conventional MA applications a finite and contiguous amount of spectrum which is designated for a particular service is allocated to multiple users. Therefore, the use of designated radio spectrum is unconstrained and can be utilized in many ways to achieve maximum efficiency. Time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA) are the three major MA techniques. In r ....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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After years of research and development, radio frequency light sources are just now becoming a mainstream lighting option. RF light sources follow the same principles of converting electrical power into visible radiation as conventional gas discharge lamps. The fundamental difference between RF lamps is that RF lamps operate without electrodes .There are three practical ways to energize RF light sources, though there are more ways to create RF plasmas. These three ways correspond to different types of interaction of electroma ....etc

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