Sampling and Aliasing
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ECTE906 – Advanced Signals & Systems
“Introductory Notes”
Graduate Coursework Programs
Module 02 (Review):
Part 1
- Sinusoids, Phase/Time-Shift
Parviz Doulai
Informatics/SECTE/2012
Main Source: The subject textbook/CD: J H McClellan, as well as;
http://users.ece.gatech.edu/mcclella/SPFirst/LectureSlides/SPFirstLectureSlides.html
Main Text: Signal Processing First, J. H. McClellan, R.W. Schafer & M.A. Yoder
From Last Week:
Analogue Signals
From
Last
Week:
Analogue
Signals
T
yp
icall
y
re
p
resented as volta
g
e or
Analogue Signal:
Af ti fti th t
yp y p g
current as a function of time.
We can use an oscilloscope to look
at a signal as a function of time
A
f
unc
ti
on o
f
ti
me
th
a
t
has a continuous range
of values “w(t)” .
at
a
signal
as
a
function
of
time
.
In general, we denote a signal (or a
waveform) by w(t).
Examples of signals:
Sinusoidal (periodic)
square wave (periodic)
Speech (aperiodic)
Pressure (aperiodic)
Pressure
(aperiodic)
ECTE906 – Introductory Notes: Graduate Coursework Programs – Signals and Systems - 2009
Page 2
Analog and Digital Signal Waveforms
From Last Week:
Analog
and
Digital
Signal
Waveforms
A f i l t f th l f th i l ti
A
wave
f
orm
i
s a p
l
o
t
o
f
th
e va
l
ue o
f
th
e s
i
gna
l
over
ti
me
Vertical axis represents the signal value or amplitude
Hi tl i tti
H
or
i
zon
t
a
l
ax
i
s represen
t
s
ti
me
The analog signal waveform changes smoothly over time
The digital signal waveform changes more suddenly
ECTE906 – Introductory Notes: Graduate Coursework Programs – Signals and Systems - 2009
Page 3
FLtWk
Discrete Time and Continuous Time Signals
F
rom
L
as
t
W
ee
k
:
Discrete
Time
and
Continuous
Time
Signals
ECTE906 – Introductory Notes: Graduate Coursework Programs – Signals and Systems - 2009
Page 4
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