<< Chapter < Page Chapter >> Page >

Question and comments

Questions or comments concerning this laboratory should be directedto Prof. Charles A. Bouman, School of Electrical and Computer Engineering, Purdue University, West Lafayette IN 47907;(765) 494-0340; bouman@ecn.purdue.edu


The purpose of this lab is to illustrate the properties of continuous and discrete-time signals using digital computersand the Matlab software environment. A continuous-time signal takes on a value at every pointin time, whereas a discrete-time signal is only defined at integer values of the “time” variable.However, while discrete-time signals can be easily stored and processed on a computer,it is impossible to store the values of a continuous-time signal for all points along a segment of the real line.In later labs, we will see that digital computers are actuallyrestricted to the storage of quantized discrete-time signals. Such signals are appropriately known as digital signals.

How then do we process continuous-time signals? In this lab, we will show that continuous-time signalsmay be processed by first approximating them by discrete-time signals using a process knownas sampling. We will see that proper selectionof the spacing between samples is crucial for an efficient and accurate approximationof a continuous-time signal. Excessively close spacing will lead to too much data,whereas excessively distant spacing will lead to a poor approximation of the continuous-time signal.Sampling will be an important topic in future labs, but for now we will use sampling to approximatelycompute some simple attributes of both real and synthetic signals.

Be sure to read the guidelines for the written reports.

Matlab review

Practically all lab tasks in the ECE438 lab will be performed using Matlab. Matlab (MATrix LABoratory) is a technical computing environmentfor numerical analysis, matrix computation, signal processing, and graphics.In this section, we will review some of its basic functions. For a short tutorial and some Matlab examples click here .

Starting matlab and getting help

You can start Matlab (version 7.0) on your workstation by typing the command


in a command window. After starting up, you will get a Matlab window.To get help on any specific command, such as “plot”, you can type the following

help plot

in the “Command Window” portion of the Matlab window. You can do a keyword search for commands related to a topic by using thefollowing.

lookfor topic

You can get an interactive help window using the function


or by following the Help menu near the top of the window.

Matrices and operations

Every element in Matlab is a matrix. So, for example, the Matlab command

a = [ 1 2 3 ]

creates a matrix named “ a ” with dimensions of 1 × 3 . The variable “ a ” is stored in what is called the Matlab workspace. The operation

b = a .'

stores the transpose of “ a ” into the vector “ b ”. In this case, “ b ” is a 3 × 1 vector.

Since each element in Matlab is a matrix, the operation

c = a * b

computes the matrix product of “ a ” and “ b ” to generate a scalarvalue for “ c ” of 14 = 1 * 1 + 2 * 2 + 3 * 3 .

Questions & Answers

what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
Privacy Information Security Software Version 1.1a
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Purdue digital signal processing labs (ece 438). OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col10593/1.4
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Purdue digital signal processing labs (ece 438)' conversation and receive update notifications?