EECS0712 Adaptive Signal Processing 2 Introduction to Adaptive Signal Processing (II) Assoc. Prof. Dr. Peerapol Yuvapoositanon Dept. of Electronic Engineering EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712 Assoc. Prof. Dr. P.Yuvapoositanon ASP2-1
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EECS0712 Adaptive Signal Processing
2
Introduction to Adaptive Signal Processing (II)
Assoc. Prof. Dr. Peerapol Yuvapoositanon
Dept. of Electronic Engineering
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-1
Content
• Digital Filters
• Overview of Adaptive Signal Processing Applications
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-2
Digital Filters
• Digital Filters is a digital device adjusting frequency and magnitude
• There are two types of Finite Impulse Response (FIR) and Infinite Impulse Response (IIR)
– FIR has no feedback
– IIR has feedback
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-3
• An FIR filter has no feedback
Finite Impulse Response (FIR)
DelayDelay
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-4
Infinite Impulse Response (IIR)
• An IIR filter has feedback
FeedbackFeedback
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-5
Transfer Function I
• Transfer function= A ratio of z-transform
• Z-Transform
z -Transform
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-6
Transfer Function
• Transfer function
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Assoc. Prof. Dr. P.Yuvapoositanon ASP2-7
Use z-Transform to find Frequency Response
• Replace z with ,
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-8
Frequency Response from Poles and Zeros
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-9
Zk= Zeros
Pk= Poles
Magni tude of
response at omega
Example
Example for Frequency Response
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-10
Example for Frequency Response
• Put together
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-11
To Summarise…
The coefficients of a Digital Filter determine the desired
frequency response.
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-12
Overview of Adaptive
Signal Processing
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-13
Why we need adaptive?
• Because environment is always changing.
• System needs to be adaptable.
• In electrical engineering, the environment is systems defined by transfer function.
EECS0712 Adaptive Signal Processing http://embedsigproc.wordpress.com/eecs0712
Assoc. Prof. Dr. P.Yuvapoositanon ASP2-14
Multipath in Wireless Communications
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Assoc. Prof. Dr. P.Yuvapoositanon ASP2-15
• Signal from transmitter may reach receiver with multipath signals
Multipath
Channel Equalisation
11 00 11 00
11 00 11..33
..66
Without multipath
With multipath
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