Delta Modulation in MATLAB

Lab Assignment 04 Delta Modulation Subject: Digital Communication Systems (EEE353) Submitted By: Muhammad Imran FA09-BEE-145 Submitted To: Sir. Asmat Ali Shah Date of Submission: April 02, 2013

LAB REPORT MATLAB Code: clear all close all clc b=0; fc=0.05; n=[0:0.3:20]; delta=0.01; x_n=sin(2*pi*fc*n); for i=1:length(n) t=(x_n(i)-b); y=sign(t); if y==1 y_n(i+1)=x_n(i)+delta; b=y_n(i+1); else y_n(i+1)=x_n(i)-delta; b=y_n(i+1); end end ffttx=fft(x_n); ffttx_a=abs(ffttx); ffty=fft(y_n); ffty_a=abs(ffty); figure(1) plot(fftshift(ffttx_a),'g') hold on plot(fftshift(ffty_a),'b') title('Spectra') xlabel('-----------f--------->') ylabel('-----------X(f)/Y(f)------>') legend('Original Signal','Modulated Signal') figure(2) plot(n,x_n,'g') hold on n1=[0 n]; stairs(n1,y_n,'b') title('Signals') xlabel('-----------t/n--------->') ylabel('-----------x(t)/y[n]------>') legend('Original Signal','Modulated Signal') legend('Original Signal','Modulated Signal')

Results: Spectra 35 Original Signal Modulated Signal

30

-----------X(f)/Y(f)------>

25

20

15

10

5

0

0

10

20

30 40 -----------f--------->

50

60

70

Signals 1.5 Original Signal Modulated Signal

-----------x(t)/y[n]------>

1

0.5

0

-0.5

-1

-1.5

0

2

4

6

8 10 12 -----------t/n--------->

14

16

18

20