An introduction
Adaptive Filter
Review by : Dhendy Zaki R
What is an Adaptive Filter?
An Adaptive filter is a signal Filter
Processing with input-output structure
signal relationship which has iterative
change parameter that adjust using
adaptive algorithm in one time instant to
the next.
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The adaptive algorithm used to update
the parameter values of the system can
take on a myriad of forms and is often
derived as a form of optimization
procedure that minimizes an error
criterion that is useful for the task at
hand. Derivation of least mean square
(LMS) algorithm most popular method
for adjusting coeficient of an adaptive
filter
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An Adaptive filter realized as a set of
program instruction running on
arithmatical processing device such
as a microprocessor, a DSP chip,
logic operations implemented on field
programmable gate array and VLSI
integrated circuit
Adaptive Filtering Problem
xn) = input signal
d(n) = desire signal
y(n) = output signal
e(n) = error signal
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Adaptive Filtering Problem
The error signal is fed into a procedure which
alters or adapts the parameters of the filter
from time n to time n+1 in a well-defined
manner. This process of adaptation is
represented by the oblique arrow that pierces
the adaptive filter block in the figure.
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Adaptive Filtering Problem
As the time index n is incremented, it is hoped
that the output of the adaptive filter becomes a
better and better match to the desired
response signal through this adaptation
process, such that the magnitude of e(n)
decreases over time
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Adaptive Filtering Problem
In the adaptive filtering task, adaptation refers
to the method by which the parameters of the
system are changed from time index n to time
index (n). The number and types of parameters
within
this
system
depend
on
the
computational structure chosen for the system
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Thank you
Reference :
Douglas, S.C. “Introduction to Adaptive Filters” Digital Signal
Processing Handbook Ed. Vijay K. Madisetti and Douglas B.
Williams Boca Raton: CRC Press LLC, 1999
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