Scilab/C4/DigitalSignalProcessing/English
Title of script: Signal processing Using Scilab
Author: Manas
Keywords: Video tutorial, Signal



Slide 1  Dear Friends,
Welcome to the spoken tutorial on “Signal Processing using Scilab” 
Slide 2 Learning Objective Slide  In this tutorial, using Scilab, I will show you how to

Slide 3System Requirement slide  To record this tutorial, I am using Ubuntu 11.04 as the operating system with Scilab 5.3.3 version 
Slide 4 Prerequisite slide  Before practicing this tutorial, a learner should have a basic knowledge of Scilab.
To know the basics of Scilab, please refer to the series of basic level spoken tutorials in Scilab....

Slide 7  In this tutorial, I will describe about 3 basic Signals.
Let me start with “Plotting continuous and discrete sine wave” 
Switch to the Scilab Console Window and type:
t = 0:0.1:2*%pi; x = sin(t); plot2d(t,x) 
Let us switch to the Scilab Console Window.
Here type:
x equal to sin of t semicolon plot 2D into bracket t comma x

Display the plot generated  This is a continous sine wave

On the console window type:
plot2d3('gnn',t,x)

Let us discuss the discrete sine wave.

Display the plot generated  This is discrete sine wave. 
Switch to Slide 7: and display 2^{nd} and 3^{rd} point of Slide 7  Let us now discuss about Plotting step function and
plotting ramp function. 
Open scilab editor.
Open the file signal.sce 
I have already written the code to generate step and ramp signal in the file called signals.sce.

Display the plot generated  Step and Ramp signal is displayed in this plot. 
Slide 8  Now let us learn how to perform different operations to analyse signals.

Swtich to Scilab console and type: x=[1,2 ,3,4]
Then type: h=[1,1,1] and then type

Let us switch to the Scilab Console window and type
x equals to within square braccket one comma two comma three comma four

Display the output generated  An output can be seen here. 
Now let us learn Discrete fourier transform for a discrete sequence by using the inbuilt command dft().  
On the Scilab console window, type: x=[1,2,3,4]

On the console window here type x equals to within square bracket one comma two comma three comma four

Display the output:
 2. + 2.i  2.  9.797D16i  2.  2.i 
The output appears as this
 2. + 2.i  2.  9.797D16i  2.  2.i 
Now I will show you how to calculate inverse discrete fourier transform. This can be done by using the same inbuilt command dft().  
On the Scilab console window:[x]=dft(xf,1)  On the Scilab console window type:
squareBracket x equals to dft within bracket xf comma 1

Display the output: 1.
2. + 5.551D17i 3.  1.225D16i 4.  5.551D16i 
This is the output.
1. 2. + 5.551D17i 3.  1.225D16i 4.  5.551D16i

Let us calculate discrete fourier transform using fft()  
Type: x= [1,2,3,4] and press Enter
Type:y = fft(x,1)
10.  2. + 2.i  2.  2.  2.i 
On the console window, type x= square [1,2,3,4] x equals to square bracket one comma two comma three comma four
Press Enter and type y = fft(x,1) y equals to fft within bracket x comma minus one Press Enter and you can see the output as these:

On the Scilab Console window type: y=[10,2+2*%i,2,22*%i] and press Enter

Let us now see how to calculate inverse discrete fourier transform by using fft().
y equals to within square bracket ten comma minus two plus two into percentage i comma minus two comma minus two minus two into percentage i.

Display the output:
x =1. 2. 3. 4. 
The output will be displayed as
x =1. 2. 3. 4. 
Let us now find out the correlation between two vectors.  
Switch to the Scilab console window
Rx1x2=1.25 0.3125 0.25  0.9375 
To do this on the Scilab console window,
Rx1x2=1.25 0.3125 0.25  0.9375 
Let us learn how to sample the given signal  
Open sampling.sce

Let me open sampling.sce where
I have already written the code in sampling.sce

Let us summarise.  
Slide 14  In this tutorial we have learnt 
Display Summary slide  How to Plot sine, step and ramp signal.

Display “About the Spoken Tutorial Project” Slide  Watch the video available at

Display “ Spoken Tutorial Workshops” slide  The Spoken Tutorial Project Team

Display “Acknowledgment”
slide 
Spoken Tutorial Project is a part

Disaplay “Contributors” slide  This script has been contributed
