Graphics Programs Reference
In-Depth Information
Hertz. In practice, this approximation is widely accepted since it accounts for
most of the signal energy.
τ
frequency
∞
∞
f
0
f
0
(
1 τ
⁄
)
f
0
+
(
1 τ
⁄
)
Figure 3.3. Amplitude spectrum for a single pulse, or a
train of non-coherent pulses.
Now consider the coherent gated CW waveform
given by
f
3
()
∞
∑
f
3
()
=
f
2
(
tnT
)
(3.23)
n
=
∞
Clearly
is periodic, where
is the period (recall that
is the
f
3
()
T
f
r
=
1
⁄
T
PRF). Using the complex exponential Fourier series we can rewrite
as
f
3
()
∞
∑
j
2π
nt
T
--------------
f
3
()
=
F
n
e
(3.24)
n
=
∞
where the Fourier series coefficients
are given by
F
n
A
τ
T
n
τπ
T
F
n
=
------
Sinc
---------
(3.25)
It follows that the FT of
is
f
3
()
Search WWH ::
Custom Search