Difference between revisions of "Scilab/C4/Digital-Signal-Processing/English"

Welcome to the spoken tutorial on “Signal Processing using Scilab”

Generate different kinds of signals , and

Perform different operations to analyse signals.

To know the basics of Scilab, please refer to the basic level spoken tutorials of Scilab....

....which is available on our website www.spoken-tutorial.org

• Plotting continuous and discrete sine wave.
• Plotting step function.
• Plotting ramp function.

Let me start with “Plotting continuous and discrete sine wave”

t = 0:0.1:2*%pi;

x = sin(t);

plot2d(t,x)

Here type:

t equal to zero colon zero point one colon two multiplied by precentage pi semicolon.

x equal to sin of t semicolon plot 2D into bracket t comma x

and press Enter key on your keyboard.

plot2d3('gnn',t,x)

On the console window type: plot two d into bracket within invertes comma gnn then comma t comma x and press Enter on your keyboard.

plotting ramp function.

Open the file signal.sce

Let us open this file signal.sce using scilab editor.

Let us execute this code.

Click on the “Execute” button in the Menu bar

Let us see how to perform Convolution between two signals.

Then type:

h=[1,1,1]

and then type

Type: convol(x,h) and press Enter

x equals to into braccket one comma two comma three comma

four

Then type h equals to into bracket one comma one comma one

Now let us apply the convoltion by typing convol opening bracket x comma h closing bracket

and press Enter on your keyboard.

Type: [xf]=dft(x,-1);

Then

Type inside bracket xf equals to dft into bracket x comma minus 1

Where x is the input vector

and flag value is -1 for DFT.

Let us press Enter

10.

- 2. + 2.i

- 2. - 9.797D-16i

- 2. - 2.i

10.

- 2. + 2.i

- 2. - 9.797D-16i

- 2. - 2.i

Bracket x equals to dft into bracket xf comma 1

Here the flag value is 1 for idft.

2. + 5.551D-17i

3. - 1.225D-16i

4. - 5.551D-16i

1.

2. + 5.551D-17i

3. - 1.225D-16i

4. - 5.551D-16i

Type:y = fft(x,-1)

Display the output:

10. - 2. + 2.i - 2. - 2. - 2.i

Press Enter and type y = fft(x,-1) y equals to fft into bracket x comma minus one

Press Enter and you can see the output as

10. - 2. + 2.i - 2. - 2. - 2.i

Type: x = fft(y,1)

and Press Enter

On the Scilab console window type

y equals to into bracket ten comma minus two plus two into percentage i comma minus two comma minus two plus minus two into percentage i.

and Press Enter

Type x = fft(y,1) x equals to fft into bracket y comma 1

and Press Enter

x =1. 2. 3. 4.

x =1. 2. 3. 4.

Type: x1=[1,2,3,4] and Press Enter

Type: x2=[1,3,1,5] and press Enter

Type Rx1x2 = corr(x1,x2,4)

The output will be displayed as

Rx1x2=1.25 0.3125 0.25 - 0.9375

Type x one equals to into braccket one comma two comma three comma fourand press Enter

Type x2 equals to into braccket one comma three comma one comma five and press Enter

Type Are x one x two equals to corr into bracket x one comma x two comma four and press Enter

The output will be displayed as

Rx1x2=1.25 0.3125 0.25 - 0.9375

Click on “Execute” button

Display the output.

I have already written the code in sampling.sce

Here click on the “Execute”button.

A plot is displayed.

To perform Linear convolution by convol().

To perform DFT and IDFT by dft().

To perform FFT by fft().

To find out the Correlation by corr().

To do the sampling

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