Generation of Sinusoidal signal through filtering 

AIM : To generate the sinusoidal signal using filter.

EQUIPMENTS:  

Operating System - Windows XP

Constructor - Simulator

Software - CCStudio 3 & MATLAB 7.5

PROGRAME:

clear all

close all

echo on

t0=.2; % signal duration

ts=0.001; % sampling interval

fc=250; % carrier frequency

fs=1/ts; % sampling frequency

t=[-t0/2:ts:t0/2]; % time vector

kf=100; % deviation constant

m=cos(2*pi*10*t); % the message signal

int_m(1)=0;

for i=1:length(t)-1 % integral of m

 int_m(i+1)=int_m(i)+m(i)*ts;

 echo off ;

end

echo on ;

u=cos(2*pi*fc*t+2*pi*kf*int_m); % modulated signal

%now lets filter the signal

[z,p] = butter(1,2*50/fs,'low');

filter_out = filter(50,[1 50],u); %this damn filter doesn't work!

subplot(2,1,1);

plot(t,u);

hold on;

plot(t,m,'r');

subplot(2,1,2);

plot(t,filter_out);

hold on;

plot(t,m,'r')

RESULT:  The sinusoidal signal is generated from  filter response for    given values .  

VIVA QUESTIONS:

1. What is the special about minimum phase filter?
2.  In signal processing, why we are much more interested in orthogonal transform?
3.  How is the non-periodic nature of the input signal handled?
4.  If a have two vectors how will i check the orthogonality of those vectors?