How to plot Message Signal using MATLAB ?? (Quick Question Need Help)
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Hi,
I have an output for a FM transmitter in the form:
y(t) = cos ( 2*pi*t + 2*pi (integral from 0,t of m(tau) dtau ) )
I need to create a message signal of the following:
m_1(t) =
{
1 when cos(t) >= 0
-1 when cos(t) < 0
}
I need to create the message signal above in MATLAB and then find the corresponding FM signal.
However, I am unclear on how to graph the message signal.. Can you please show me how?
Thank you.
采纳的回答
Richard Brown
2012-4-23
First, note that the integral of the message will be zero up to any multiple of 2*pi. The integral will then be a piecewise linear function that only requires evaluating on [0,2*pi). It's straightforward to do this by hand
pp = interp1([0, pi/2, 3*pi/2, 2*pi], [0, pi/2, -pi/2, 0], 'linear', 'pp');
int_m = @(t) ppval(pp, mod(t, 2*pi));
Then a plot of your FM signal will be
fplot(@(t) cos(2*pi*t) + 2*pi*(int_m(t)), [0 20])
更多回答（2 个）
Richard Brown
2012-4-23
m_1 = @(t) 2*(cos(t) >= 0) - 1
t = linspace(0, 100);
stairs(t, m_1(t))
3 个评论
PG
2012-4-23
Richard Brown
2012-4-23
No, don't do that, it will be horrible!! (not wrong, just horrible)
See new answer below
PG
2012-4-23
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