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17
PRODUCT SPECIFICATION
RC4200
The maximum and minimum values for I
1
and I
2
lead to:
For a dynamic range of N, where
)
A min.
)
These equations combine to yield:
V
(max.)
5
N
–
(
)
50
m
A
O
= K R
R
=
Example 1
V
Y
= Asin
w
t 2.5V
£
A
£
10V, therefore N = 4
0V
£
V
M
£
10V, therefore V
X
(max.) = 10V
K = 1, therefore V
0
= V
M
sin
w
t
Example 2
V
Y
= Asin
w
t 3
£
A
£
6, therefore N = 2
0V
£
V
M
£
8V, therefore V
X
(max.) = 8V
K = 0.2, therefore V
0
= 0.2 V
M
sinwt
so:
R
1
= 53.3K, R
2
= 40K
R
a
= 60K and R
0
= 7.11K
I
1
(max.)
V
max.
(
R
1
)
------------------------
V
max.
(
R
a
)
------------------------
+
250
m
A
=
=
I
1
(min.)
V
min.
(
R
a
)
-----------------------
50
m
A V
M
min.
(
)
0
=
=
=
I
2
(max.)
R
2
)
A max.
V
max.
(
R
a
)
------------------------
+
250
m
A
=
=
I
2
(min.)
V
min.
(
R
a
)
-----------------------
50
m
A
=
=
N
A max.
5,
<
=
R
1
--------------------------------, R2
N
–
)
50
m
A
5
(
-----A(max.)
=
R
a
------------------ and R
50
m
A
R
a
-------------,
R
1
V
(max.)
50
m
A
50
m
A
50
m
A
KR
R
2
R
a
-----------------------
50
m
A
50
m
A
50
m
A
--10V
200K
=
=
=
R
1
A(max.)
--10V
200K
=
=
=
R
a
A(min.)
-2.5V
50K
=
=
=
R
O
-------------
1---------------------------------
200K
′
50K
800K
=
=
=
Figure 16. Amplitude Modulator with A.G.C.
65-1866
RC4200
Multiplier
V
S
M
Y
O
S
R1
100
-V
R
+V
S
-V
3
6
4
5
8
7
1
2
V
30K
1/4
RC4156
10K
R*
30K
470
R1
S
-V
S
+V
R2
R1 R
a
R
a
R
a
A
30K
100
m
0.1 F
m
0.1 F
S
-V
S
+V
R2 R
a
m
0.1 F
1/4
RC4156
1/4
RC4156
R3
R2
R3
30K
30K
R3
30K
1/2 R3
15K
1N914
1N914
10K
10K
=
SIN
w
t
R
a
R
a
V =
V sin
t
C1
R3 47K
p
2
V = 2
p
w
t
*R1 R2 R
a
R
O