dc

10. Tutorial class sheets
UNIT-1
SAMPLING:
Sampling Theorem for strictly band - limited signals
1.a signal which is limited to W
f W , can becompletely
n
described by g(
) .
2W
n
2.The signal can becompletely recovered from g(
)
2W
Nyquist rate 2W
Nyquist interval 1
2W
When the signal is not band - limited (under sampling)
aliasing occurs.To avoid aliasing, we may limit the
signal bandwidth or have higher sampling rate.
FromTable
g( t)
n
1
G(
f )
T
m
g
G
or G
s
( t)
s m
f G(
f
( f )
( f )
f
mf
n
s
m
s
s
( f
s
G(
f
s
m
T
f G(
f ) f
s
mf
or we may apply Fourier Transform on(3.1)
( t nT )
A6.3 we have
)
)
g(
nT )exp( j2
nf T )
s
s
m
m
0
)
G(
f
s
mf
s
)
(3.2)
(3.3)
(3.5)
to obtain