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To make suitable to requirements or conditions
Adjust or modify fittingly
To adjust oneself to different conditions, environments
Definition
Characteristics
Self optimize to nonstationary environment
Programmed by a training process
Self-designing
They can extrapolate the model behavior to deal withnew situations after training.
Repair themselves
Nonlinear systems with time varying parameters.
More complex & difficult to analyze than nonadaptivesystems but offer the possibility of substantial increasedsystem performance when input signal characteristicsare unknown or time varying.
Application
Communications
Radar
Sonar
Seismology
Mechanical design
Navigation systems
Biomedical electronics
Classification
Open-loop adaptation Make measurements of input or environmental characteristics
Apply these information to some formula / computational algorithm
Use results to set adjustments of the adaptive system
Closed-loop adaptation Automatic experimentation with the adjustments and knowledge of
their outcome in order to optimize a measured system
performance.
Called performance feedback process.
Open-loop adaptation
Output
signalOther
data
Output
signal
Input data
Signal
processor
Display
Concept
Signal processor
Adaptive
algorithm
Input data
Other
data
Equivalent System
Processor
Closed-loop adaptation
Other
data
Output
signal
Input
data
Performance
Calculation
Performance
Display
Concept
Processor
Processor
Adaptive
algorithm
Performance
Calculation
Input data
Other
data
Output
signal
Equivalent
Applications of Closed-loop adaptation
Adaptive
ProcessorDelay
ds
xy
+
-
Prediction
Adaptive
Processor
Plant
ds
x y
+
-
System Identification
Cont..
Adaptive
ProcessorChannel
ds
xy
+
-
+
+
Noise
Delay
Cont..
Equalization / Deconvolution / inverse filtering /
inverse modeling
Adaptive
Processor
ds+n
x y
+
-n
Cont..
Interference canceling
k
z-1
dk=2 cos(2k/N)
w0 w1
yk=w0xk+ w1xk-1
xk= sin(2k/N)
Cont..
Linear Filter / Linear combiner
900
LMS
Algorithm
Reference
input
DelayW1
W2
+
+
+
-
To 60 Hz
wall outlet
60 Hz
interference
ECG
preamplifier
Primary input
To ECG
recorder
Adaptive noise canceller Cont..
Canceling 60-Hz interference in electrocardiography
1
2
3
4
Refe
ren
ce i
np
uts
Abdominal lead (Primary input)
Cont..
+
_Output
CANCELING THE MATERNAL ECG IN FETAL ELECTROCARDIOGRAPHY
Cont..
HybridAdaptive
filter
Delay
Adaptive
filter Hybrid
Long-distance system with adaptive-echo suppressors
Delay+
+
-
-
Hybrid Echo
Suppressor
Delay
Delay
Echo
SuppressorHybrid
Relay
Relay
Long-distance system with echo suppressors
Cont..
Adaptive
Filterz
Delay
Broadband
interference
Periodic
signal
Primary input
Reference input
Periodic
signal
Active noise canceller
Adaptive noise canceller as self-tuning filter
+
-
Cont..
Adaptive
Filterz
Delay
Input
Filter transfer
function
Adaptive line enhancer
+
-
Fast Fourier
Transform
Weight values