Adaptive Systems1
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Transcript of Adaptive Systems1
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To make suitable to requirements or conditions
Adjust or modify fittingly
To adjust oneself to different conditions, environments
Definition
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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.
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Application
Communications
Radar
Sonar
Seismology
Mechanical design
Navigation systems
Biomedical electronics
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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.
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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
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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
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Applications of Closed-loop adaptation
Adaptive
ProcessorDelay
ds
xy
+
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Prediction
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Adaptive
Processor
Plant
ds
x y
+
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System Identification
Cont..
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Adaptive
ProcessorChannel
ds
xy
+
-
+
+
Noise
Delay
Cont..
Equalization / Deconvolution / inverse filtering /
inverse modeling
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Adaptive
Processor
ds+n
x y
+
-n
Cont..
Interference canceling
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k
z-1
dk=2 cos(2k/N)
w0 w1
yk=w0xk+ w1xk-1
xk= sin(2k/N)
Cont..
Linear Filter / Linear combiner
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900
LMS
Algorithm
Reference
input
DelayW1
W2
+
+
+
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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
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1
2
3
4
Refe
ren
ce i
np
uts
Abdominal lead (Primary input)
Cont..
+
_Output
CANCELING THE MATERNAL ECG IN FETAL ELECTROCARDIOGRAPHY
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Cont..
HybridAdaptive
filter
Delay
Adaptive
filter Hybrid
Long-distance system with adaptive-echo suppressors
Delay+
+
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Hybrid Echo
Suppressor
Delay
Delay
Echo
SuppressorHybrid
Relay
Relay
Long-distance system with echo suppressors
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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
+
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Fast Fourier
Transform
Weight values