Digital Signal Processing Reference
In-Depth Information
1.0
0.8
Positive
frequency
Negative
frequency
0.6
0.4
0.2
0
500
1000
1500
2000
(Sample number)
(Frequency, GHz)
0
50
+
/
−
100
−
50
0
(a)
1.0
0.8
0.6
Negative
frequency
Positive
frequency
0.4
0.2
0
500
1000
1500
2000
500
1000
1500
2000
(Sample number)
(b)
Figure 9-23
For Example 9-7: (a) magnitude of the frequency spectrum constructed
by appending the measured positive frequency values of
S
21
and the complex conjugate
to create the negative frequency values; (b) FFT periodic treatment of the sampled data
allows a more intuitive look at the magnitude of the frequency response when windowed
properly.
2.0
1.5
1.0
0.5
0.0
2.75
3.00
3.25
3.50
3.75
4.00
Time, ns
Figure 9-24
Impulse response calculated from the inverse FFT of the
S
21
data shown
in Figure 9-23.
Search WWH ::
Custom Search