TSH350_07 STMICROELECTRONICS [STMicroelectronics], TSH350_07 Datasheet - Page 16

• Manufacturer Part Number: TSH350_07
• Description: 550MHz low noise current feedback amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Intermodulation distortion product
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Intermodulation distortion product
The non-ideal output of the amplifier can be described by the following series:
where the input is V
the amplitude of the harmonics of the output signal V
A one-frequency (one-tone) input signal contributes to harmonic distortion. A two-tone input
signal contributes to harmonic distortion and to the intermodulation product.
The study of the intermodulation and distortion for a two-tone input signal is the first step in
characterizing the driving capability of multi-tone input signals.
In this case:
then:
From this expression, we can extract the distortion terms, and the intermodulation terms
from a single sine wave:
●
●
The intermodulation product of the driver is measured by using the driver as a mixer in a
summing amplifier configuration (see
external mixing device is avoided.
Figure 33. Inverting summing amplifier (using evaluation board SO8_S_MULTI)
second order intermodulation terms IM2 by the frequencies (
amplitude of C2A
third order intermodulation terms IM3 by the frequencies (2
and (
V
out
=
1
C
0
2
+
) with an amplitude of (3/4)C3A
C
1
in
A
=Asin t, C
sin
2
V
V
V
V
in2
in2
in1
in1
V
1
t
out
+
V
A
in
=
sin
0
=
C
is the DC component, C
R
R
R
R
0
A
2
1
1
2
2
+
t
sin
C
Figure
R
R
+
1
C
V
1
t
2
in
+
A
+
A
33). In this way, the non-linearity problem of an
sin
C
sin
+
+
_
_
2
3
V
1
2
2
t
R
R
in
t
+
fb
fb
+
A
out
sin
+
.
1
C
2
(V
n
t
V
in
2
n
) is the fundamental and C
in
+
V
V
C
1
out
out
-
n
1
100
100
-
2
A
), (2
2
sin
) and (
1
1 2
t
+
A
), (
1 2
sin
) with an
1
2
+2
TSH350
t
n
2
n
)
is