The Laboratory Exercise questions given to the students based on real time signal analysis case

1. EX.NO-1:SAMPLING AND ALIASING EFFECTS
January 28,
2016
Dr.C.Muniraj | EEE-KSRCT
Problem Ex2.1
A single phase inverter with filter supply the three different frequency (25Hz,35Hz,50Hz)output
voltage waveform to single phase induction motor for the speed control operations. Generate
the discrete voltage waveform for the above different frequency by the sampling frequency of
15 Hz, 50Hz, 100Hz, 200Hz. write your comments on aliasing effects.
sample progrmme
% sampling and aliasing effects
clear all
close all
clc
% lest assume signal having three frequency values
f1=50;%Hz
f2=100;%Hz
f3=200;%Hz
% Let assume the different sampling frequecy values
Fm1=100;%Hz(F<2fm)
Fm2=200;%Hz (Fm=fm)
Fm3=400; %Hz(Fm=2fm)
Fm4=800; %Hz(Fm>2fm)
% volage equation for sampling freqency Fm1
T=[0:1/Fm2:0.04];
Vm=1;
V1=Vm*sin(2*pi*f1*T);
V2=Vm*sin(2*pi*f2*T);
V3=Vm*sin(2*pi*f3*T);
% plot the voltage waveforms
figure(1)
plot(T,V1,'-or');
hold on
plot(T,V2,'-ko');
hold on
plot(T,V3,'-g*');
legend ('50Hz','100Hz','200Hz')
xlabel('samples')
ylabel('magnitude')