HP (Hewlett-Packard) 50g ユーザーズマニュアル

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Page 16-42
     
The solution is shown below:
Fourier Transforms
Before presenting the concept of Fourier transforms, we’ll discuss the general 
definition of an integral transform.   In general, an integral transform is a 
transformation that relates a function f(t) to a new function F(s) by an integration 
of the form 
  The function 
κ(s,t) is known as the 
kernel of the transformation.
The use of an integral transform allows us to resolve a function into a given 
spectrum of components.  To understand the concept of a spectrum, consider 
the Fourier series
representing a periodic function with a period T.   This Fourier series can be re-
written as 
 where 
for n =1,2, …   
=
b
a
dt
t
f
t
s
s
F
.
)
(
)
,
(
)
(
κ
(
)
,
sin
cos
)
(
1
0
=
+
+
=
n
n
n
n
n
x
b
x
a
a
t
f
ω
ω
=
+
+
=
1
0
),
cos(
)
(
n
n
n
n
x
A
a
x
f
φ
ϖ
,
tan
,
1
2
2
⎟⎟⎠
⎜⎜⎝
=
+
=
n
n
n
n
n
n
a
b
b
a
A
φ