DĆ4
W
R
+ e
*j
2p
R
" $( #$ *+
$ * &)
% * (
%#&+* )
FFT
mag
(k) + A(k)
2
) B(k)
2
Ǹ
FFT
phase
(k) + acrtan
ǒ
B(k)
A(k)
Ǔ
-(
(" &(* %
# $(/ &(* %
#$ *+ $ &) %( $* , ('+$ ) ( )( $ " $(
$*(&%"* %$ ) +) *% .&$ * &%) * , ('+$ ) *% "" * $* (
(%( "$*
#$ *+ % * ('+$/ )&*(+# $ ") ) ,$ )
FFT
magdB
(k) + 20log(FFT
mag
(k))
-( * &% $* ) $ ) * ) $ -, % &!
- ,) # $*% W
)"* - $%- $ +$* %$ ) &&" *% * * #0%# $ -,0
%(# %( * ) %#&+* - $%- $ +$* %$) ( )
%""%-)
H *$+"(
+
*
+
H ( $+"(
x(n) +
R
2
|
n + 0
(2 * 2
n
R
),
R * 1
|
n +
R
2
(2 * 2
n
R
)
H $$ $
x(n) +
R * 1
|
n + 0
0.5(1 * cos
(
2p
n
R
)
)
H ## $
x(n) +
R * 1
|
n + 0
0.54 * 0.46(1 * cos(2p
n
R
))