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