4/17/08
test:
3 problems
1 sampling
1 like #3
1 like #4
bring calc

f(t)=sinc(200pi*t)
p(t)=sum<n=<inf>>(del(t-nT))
T=1/200 seconds
F(w)=rect(w/400pi) -> BW=100Hz -> nyquist rate =fn=200Hz -> sampling rate=fs=200Hz
if sampled signal was passed through ideal low pass filter 
H(w)=rect(w/400pi)
Y(w)=H(w)Fs(w)
Fs(w) = sampled signal
see (Fig1)
problem number 3, the chart with arrows n shit (Fig2)
problem number 4, DT low pass bandwidth filter with warping (Fig3)