12

|

2 Fundamentals of Information, Signal and System Theory

hold on

plot(th,csh)

% continuous representation

% Amplitude modulation

am = (1+is).*cs;

amh = (1+ish).*csh;

subplot(7,1,3)

plot(t,Ac.*(1+is),'r')

hold on

stem(t,am)

% discrete representation

plot(th,amh)

% continuous representation

% Frequency modulation

mi = 16;

fm = sin(2*pi*fc*t+(mi.*is));

fmh = sin(2*pi*fc*th+(mi.*ish));

subplot(7,1,4);

stem(t,fm);

% discrete representation

hold on

plot(th,fmh)

% continuous representation

% Pulse amplitude modulation

subplot(7,1,5)

plot(t,Ac.*(1+is),'r')

hold on

bar(t,am)

% discrete representation

plot(th,amh)

% continuous representation

% Pulse position modulation

subplot(7,1,6);

ppm = modulate(is,fc,fs,'ppm');

tp = 1:length(ppm);

tp = 10*tp./N./length(is);

% appropriate time base

bar(tp,ppm, 2);

% discrete representation

axis([0 5 0 1.1])

% Pulse width modulation

subplot(7,1,7);

pwm = modulate(is,fc,fs,'pwm');

bar(tp,pwm,1);

% discrete representation

axis([0 5 0 1.1])