Figure 1 shows the periodic rectangular pulses
x(t)
whose period is
T(=(1)/(f_(0)))
. The Fourier series expansion of
x(t)
is given as
x(t)=\sum_(n=-\infty )^(\infty ) D_(n)e^(j2\pi nf_(0)t).
Derive the coefficient
D_(n)
. Let's input the above periodic rectangular pulses
x(t)
into the ideal low-pass filter whose cut-off frequency is
y(t)\tau ->0x(t)x(t)s(t)S(f)s(t)g(t)G(f)g_(s)(t)g(t)f_(s)G_(S)(f)g_(s)(t)G_(S)(f)f=-3Bf=3B