29-02-2012, 03:22 PM
ADAPTIVE SMART ANTENNA
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SWITCH BEAM ANTENNA
This system consists of fixed numbers of predefined configurations that can be accessed.
It detects the signal strength, switch from one beam to another.
Combine the outputs of multiple antennas in such a way as to form finely directional with more selectivity.
ADAPTIVE SMART ANTENNAS
This array antennas are the most advanced smart antennas.
This system uses new variety of multiple antennas and algorithms in order to maximize the strength of the signal being send and received by reducing the effect of interference or noise.
They can effectively locate, track, identify, minimize the interfering signals and increase the signal reception.
This point makes them more versatile and better than switch beam antennas.
ADAPTIVE BEAM FORMING
Adaptive beam forming is a powerful technique of enhancing a signal of interest while suppressing the interference signal and the noise at the output of an array of sensors.
Accomplished by phasing the feed to each element of an array so that signals received or transmitted from all elements will be in phase in a particular direction.
LMS ALGORITHM
Least mean squares algorithms are a class of adaptive filter used to mimic a desired filter by finding the filter coefficients that relate to producing the least mean squares of the error signal.
It requires no direct matrix inversion and memory.
It uses steepest descent method and updates the weight vector.
Calculations are easy to compute and its applicable to real time applications.
