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Question or 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

Introduction

A discrete-time system is anything that takes a discrete-time signal as input and generates a discrete-time signal asoutput. A more general behavioral view of systems is anything that imposes constraints on a set of signals. The concept of a system is very general. It may be used to model the response of an audio equalizer or theperformance of the US economy.

In electrical engineering, continuous-time signals are usually processed by electrical circuits described by differential equations.For example, any circuit of resistors, capacitors and inductors can be analyzed using mesh analysis to yield a system of differentialequations. The voltages and currents in the circuit may then be computedby solving the equations.

The processing of discrete-time signals is performed by discrete-time systems.Similar to the continuous-time case, we may represent a discrete-time system either by a set ofdifference equations or by a block diagram of its implementation. For example, consider the following difference equation.

y ( n ) = y ( n - 1 ) + x ( n ) + x ( n - 1 ) + x ( n - 2 )

This equation represents a discrete-time system . It operates on the input signal x ( n ) to produce the output signal y ( n ) . This system may also be defined by a system diagram as in [link] .

Diagram of a discrete-time system. (D = unit delay)

Mathematically, we use the notation y = S [ x ] to denote a discrete-time system S with input signal x ( n ) and output signal y ( n ) . Notice that the input and output to the system are the completesignals for all time n . This is important since the output at a particular timecan be a function of past, present and future values of x ( n ) .

It is usually quite straightforward to write a computer program to implement a discrete-time system from its difference equation.In fact, programmable computers are one of the easiest and most cost effective ways of implementingdiscrete-time systems.

While equation [link] is an example of a linear time-invariant system, other discrete-time systems may be nonlinear and/or time varying.In order to understand discrete-time systems, it is important to first understand their classificationinto categories of linear/nonlinear, time-invariant/time-varying, causal/noncausal, memoryless/with-memory, and stable/unstable.Then it is possible to study the properties of restricted classes of systems, such as discrete-time systems which are linear, time-invariantand stable.

Background exercises

Submit these background exercises with the lab report.

Example discrete-time systems

Discrete-time digital systems are often used in place of analog processing systems.Common examples are the replacement of photographs with digital images, and conventional NTSC TV with directbroadcast digital TV. These digital systems can provide higher quality and/orlower cost through the use of standardized, high-volume digital processors.

Questions & Answers

how can chip be made from sand
Eke Reply
are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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
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