- #1
kidd
- 15
- 0
The question is like this:
a.The amplitude modulation(AM)waveform in time and frequency domain.
fm=20HZ,fc=500HZ,Vm=1V,Vc=1V,t=0:0.00001:0.09999
a.The frequency modulation(FM)waveform in time and frequency domain.
fm=250HZ,fc=5KHZ,Vm=1V,Vc=1V,m=10,t=0:0.00001:0.09999
Then my program is like this:
% setting
fm=20;
fc=500;
vm=1;
vc=1;
interval=0.001;
% x-axis:Time(second)
t=0:0.00001:0.09999;
f=0:1:9999;
% y-axis:Voltage(volt)
wc=2*pi*fc;
wm=2*pi*fm;
V1=vc+vm*sin(wm*t);
V2=-(vc+vm*sin(wm*t));
Vm=vm*sin(wm*t);
Vc=vc*sin(wc*t);
Vam=(1+sin(wm*t)).*(sin(wc*t));
Vf=abs(fft(Vam,10000))/10000;
% Plot figure in time domain
figure;
plot(t,Vam);
hold on;
plot(t,V1,'r'),plot(t,V2,'r');
title('AM waveform time-domain');
xlabel('time'), ylabel('amplitude');
grid on;
% Plot figure in frequency domain
figure;
plot(f*10,Vf);
axis([(fc-2*fm) (fc+2*fm) 0 0.6]);
title('AM waveform frequency-domain');
xlabel('frequency'), ylabel('amplitude');
grid on;
%Plot modulating signal
figure;
plot(t,Vm);
title('AM modulating signal');
xlabel('time'), ylabel('amplitude');
grid on;
%Plot carrier signal
figure;
plot(t, Vc);
title('AM carrier signal');
xlabel('time'), ylabel('amplitude');
grid on;
clear;
Is it correct?It is AM program.If it is wrong can u help me correct it?
% setting
vc=1;
vm=1;
fm=250;
fc=5000;
m=10;
% x-axis:Time(second)
t=0:0.00001:0.09999;
f=0:10:99990;
% y-axis:Voltage(volt)
wc=2*pi*fc;
wm=2*pi*fm;
sc_t=vc*cos(wc*t);
sm_t=vm*cos(wm*t);
kf=1000;
s_fm=vc*cos((wc*t)+10*sin(wm*t));
vf=abs(fft(s_fm,10^4))/5000;
% Plot figure in time domain
figure;
plot(t,s_fm);
hold on;
plot(t,sm_t,'r');
axis([0 0.01 -1.5 1.5]);
xlabel('time(second)'),ylabel('amplitude');
title('FM time-domain');
grid on;
% Plot figure in frequency domain
figure;
plot(f,vf);
axis([ 0 10^4 0 0.4]);
xlabel('frequency'), ylabel('amplitude');
title('FM frequency-domain');
grid on;
%Plot modulating signal
figure;
plot(t,sm_t);
axis([0 0.1 -1.5 1.5]);
title('FM modulating signal');
This is FM.
And can let me know what can i get discussion and conclution from this two program?I not very sure i understand what is it doing...
a.The amplitude modulation(AM)waveform in time and frequency domain.
fm=20HZ,fc=500HZ,Vm=1V,Vc=1V,t=0:0.00001:0.09999
a.The frequency modulation(FM)waveform in time and frequency domain.
fm=250HZ,fc=5KHZ,Vm=1V,Vc=1V,m=10,t=0:0.00001:0.09999
Then my program is like this:
% setting
fm=20;
fc=500;
vm=1;
vc=1;
interval=0.001;
% x-axis:Time(second)
t=0:0.00001:0.09999;
f=0:1:9999;
% y-axis:Voltage(volt)
wc=2*pi*fc;
wm=2*pi*fm;
V1=vc+vm*sin(wm*t);
V2=-(vc+vm*sin(wm*t));
Vm=vm*sin(wm*t);
Vc=vc*sin(wc*t);
Vam=(1+sin(wm*t)).*(sin(wc*t));
Vf=abs(fft(Vam,10000))/10000;
% Plot figure in time domain
figure;
plot(t,Vam);
hold on;
plot(t,V1,'r'),plot(t,V2,'r');
title('AM waveform time-domain');
xlabel('time'), ylabel('amplitude');
grid on;
% Plot figure in frequency domain
figure;
plot(f*10,Vf);
axis([(fc-2*fm) (fc+2*fm) 0 0.6]);
title('AM waveform frequency-domain');
xlabel('frequency'), ylabel('amplitude');
grid on;
%Plot modulating signal
figure;
plot(t,Vm);
title('AM modulating signal');
xlabel('time'), ylabel('amplitude');
grid on;
%Plot carrier signal
figure;
plot(t, Vc);
title('AM carrier signal');
xlabel('time'), ylabel('amplitude');
grid on;
clear;
Is it correct?It is AM program.If it is wrong can u help me correct it?
% setting
vc=1;
vm=1;
fm=250;
fc=5000;
m=10;
% x-axis:Time(second)
t=0:0.00001:0.09999;
f=0:10:99990;
% y-axis:Voltage(volt)
wc=2*pi*fc;
wm=2*pi*fm;
sc_t=vc*cos(wc*t);
sm_t=vm*cos(wm*t);
kf=1000;
s_fm=vc*cos((wc*t)+10*sin(wm*t));
vf=abs(fft(s_fm,10^4))/5000;
% Plot figure in time domain
figure;
plot(t,s_fm);
hold on;
plot(t,sm_t,'r');
axis([0 0.01 -1.5 1.5]);
xlabel('time(second)'),ylabel('amplitude');
title('FM time-domain');
grid on;
% Plot figure in frequency domain
figure;
plot(f,vf);
axis([ 0 10^4 0 0.4]);
xlabel('frequency'), ylabel('amplitude');
title('FM frequency-domain');
grid on;
%Plot modulating signal
figure;
plot(t,sm_t);
axis([0 0.1 -1.5 1.5]);
title('FM modulating signal');
This is FM.
And can let me know what can i get discussion and conclution from this two program?I not very sure i understand what is it doing...