U
niversity of
S
outhern
C
alifornia
USC Viterbi School of Engineering
Ming Hsieh Department of Electrical Engineering
EE 541: Homework #07
Fall, 2010
Due: 11/16/2010
Choma
Problem #31:
A particular type of multiloop feedback amplifier is designed to deliver a
driving point input impedance,
Z
in
(s)
, that is identical to the Thévenin equivalent resistance,
R
,
of the signal source,
V
s
.
Although the design achieves
Z
in
(s) = R
at low signal frequencies, the
input impedance degrades at high signal frequencies in accordance with the model shown in
Figure (P31a).
Note therein that
Z
in
(s)
matches the signal source resistance at low frequencies
but degrades toward zero at high frequencies.
Compensate for this input impedance response by
introducing an appropriate impedance,
Z(s)
, in series with the signal source and the input port, as
suggested in Figure (P31b). It is to be understood that the objective of
Z(s)
is to ensure that the
indicated impedance,
Z
t
(s)
, is identical to
R
for all signal frequencies.
The
Z(s)
adopted for this
compensation scheme should exploit interconnections of only passive, lumped elements.
Show
a schematic diagram of
Z(s)
, with all element values thereof expressed in terms of model resis
tances
R
1
and
R
and capacitances
C
1
and
C
2
.
R
1
Z (s)
in
R
C
2
V
i
C
1
R
V
s
+
−
(a).
R
1
Z (s)
in
R
C
2
V
i
C
1
R
V
s
+
−
(b).
Z(s)
Z (s)
t
V
t
Figure (P31)
(a).
Design the network shown in Figure (P24b) if
R = 50
Ω
,
C
1
= 20 fF
,
C
2
= 3 fF
, and
R
1
=
75
.
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 '06
 Choma
 Amplifier, Frequency, Input impedance, Impedance matching, Electrical parameters, Output impedance, signal source

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