[matlab] matlab simulation modulation system FM system

Catalog

1、FM System

2、 wave form

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1、FM System

clear all;
close all;
clc;
Kf = 5; % FM index 
fc = 10; % Carrier center frequency 
dt = 0.001;
T = 10;
t = 0:dt:T;
% Generate baseband signal 
fm = 1;
%mt = cos(2*pi*fm*t) + 1.5*sin(2*pi*0.3*fm*t);
mt = cos(2*pi*fm*t);
%FM  modulation 
A = sqrt(2);
%mt  Integral function of 
%mti = 1/2/pi/fm*sin(2*pi*fm*t) -3/4/pi/0.3/fm*cos(2*pi*0.3*fm*t);
mti = (1/(2*pi*fm))*sin(2*pi*fm*t) ;
st = A*cos(2*pi*fc*t + 2*pi*Kf*mti);
figure;
subplot(3,1,1); plot(t,st,'b-');
hold on; plot(t,mt,'r:');
xlabel('t (s)'); title('FM  FM signal ');
grid on;
%FM  Power spectrum of modulated signal 
[f sf] &