Re: AM modulation concept
for example, if I have a pulse train, with ζ pulse width, and T = 5*ζ
in Fourier series:
f(t) = Co + ∑ [Cn * cos (nωot + Φn)]
and
Cn = (ζ/T)*A*Sa(n*pi*ζ/T)
where:
Co: DC component
n: number of the harmonic
Φ: phase
ζ: pulse width
T: period of the pulse trains or 1/frequence
Sa: Sample function (sen x)/x
The Amplitud modulation is:
[Eo + K*a(t)]*cos ωct
where:
Eo: Carrier amplitud
K: modulator constant
ωc: carrier frequency
a(t): information signal
Do I have to substitute a(t) by f(t) and make the calculus? How many harmonics do I have to consider for represent the right frequency spectrum and recover the same pulse trains at the demodulator??