RHF350 STMICROELECTRONICS [STMicroelectronics], RHF350 Datasheet - Page 14

• Manufacturer Part Number: RHF350
• Description: Rad-hard 550 MHz low noise operational amplifier
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Intermodulation distortion product
5
14/23
Intermodulation distortion product
The non-ideal output of the amplifier can be described by the following series of equations.
Equation 8
Where the input is V
is 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:
Equation 9
then:
Equation 10
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 (
external mixing device is avoided.
Second-order intermodulation terms IM2 by the frequencies (
an amplitude of C2A
Third-order intermodulation terms IM3 by the frequencies ( 2
(
V
out
1
+ 2
=
C
2
0
) and (
+
C
1
in
A
1
sin
= Asin t , C
2
V
1
.
2
t
out
) with an amplitude of (3/4)C3A
+
V
A
in
Doc ID 15604 Rev 4
=
sin
=
C
0
0
is the DC component, C
A
2
Figure 27
+
t
sin
C
+
1
C
V
1
t
2
in
+
A
+
A
sin
). In this way, the non-linearity problem of an
C
sin
2
V
1
2
2
t
in
t
+
+
A
sin
out
+
C
.
2
n
1
t
3
V
( V
.
2
n
in
in
+
) is the fundamental and C
C
1
n
1
-
A
-
sin
2
), ( 2
2
) and (
1
t
+
1
A
sin
1
2
),
2
RHF350
t
2
) with
n
n