FPGA Central

Hi there, i was just playing around with the modulation function o
Matlab

here are the simple commmands I run:

» t = 5;
» t=0:0.01:10;
» y=power(sin(pi*t/(2*T)), 0.5);
» mod = modulate(y, 250, 44100, 'am');
» plot(t, mod)

so I wanted to know what I should choose my sampling frequency to be
right now it is set to 44100, but how do I know this is appropriate? Whe
I plot (t,mod), it seems that it is very dependent on the samplin
frequency. Try my commands out yourself and you will see what I mean,
but can someone explain to me why this is such an issue? I woudl hav
thought that as long as my sampling frequency was greater than 2*fc (wher
fc in this example is set to be 250) then it wouldnt matter if I set m
sampling frequency to be at something much greater than the nyquist rat
like 44100 or 88200 for example; but plotting:

» mod = modulate(y, 250, 44100, 'am');

gives me a much different graph than plotting:

» mod = modulate(y, 250, 88200, 'am');

I just dont understand theoretically, if someone could explain it owuld b
great!
thank you!!!
-L

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oops sorry I did a typo, it should actually be:

» T = 5;
» t=0:0.01:10;
» y=power(sin(pi*t/(2*T)), 0.5);
» mod = modulate(y, 250, 44100, 'am');
» plot(t, mod)


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