Keysight Technologies N9322C, User Manual

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Functions and Measurements
Making Distortion Measurements
56
Third-Order Intermodulation Distortion
Two- tone, third- order intermodulation distortion is a
common specification in communication systems. When two
signals are present in a non- linear system, they may interact
and create third- order intermodulation distortion (TOI)
products that are located close to the original signals.
System components such as amplifiers and mixers contribute
to the generation of these distortion products.
This example will test a device for third- order
intermodulation through the use of markers. Two sources
are used, one set to 300 MHz and the other to 301 MHz.
1
Connect the equipment as shown in figure below. This
combination of signal generators, low pass filters, and
directional coupler (used as a combiner) results in a
two- tone source with very low intermodulation distortion.
Although the distortion from this setup may be better than
the specified performance of the analyzer, it is useful for
determining the TOI performance of the source/analyzer
combination. After the performance of the source/analyzer
combination has been verified, the device- under- test (DUT)
(for example, an amplifier) would be inserted between the
directional coupler output and the analyzer input.
Frequency
Enter
7 MOD
On/ Off
RF
4
1
0
2
9
6
3
On/ Off
Amplitude FM
Utility
LF Out
Preset
Local
AM I/ Q
File
Trigger Pulse M
·
Sweep
8
FUNCTIONS
LF OUT RF OUT 50
Remote
Standby
On
N9310A RF Signal Generator 9 kHz - 3.0 GHz
5
REVERSE PWR
4W MAX 30VDC
Frequency
Enter
7 MOD
On/ Off
RF
4
1
0
2
9
6
3
On/ Off
Amplitude FM
Utility
LF Out
Preset
Local
AM I/ Q
File
Trigger Pulse M
·
Sweep
8
FUNCTIONS
LF OUT RF OUT 50
Remote
Standby
On
N9310A RF Signal Generator 9 kHz - 3.0 GHz
5
REVERSE PWR
4W MAX 30VDC
Remote
Standby
On TG SOURCE CAL OU T
50M Hz 10dBm
7
·
4
1
0
2
5
8 9
6
3 Back
Enter
M arker
Peak
Search
M arker
Auto
Tune
Det/
Display
File/
Print
BW /
Avg
View /
Trace
Meas
MODE
Sw eep/
Trig
Local
Save
N9320A SPECTRUM ANALYZER 9 kHz - 3.0 GHz
PROBE POWER
RF IN 50
50V DC M AX
30dBm 1W M AX
CAT Ⅱ
Signal Generator Signal Generator
Spectrum Analyzer
Directional Coupler
RF OUT
RF IN
300 MHz LOW
PASS FILTER
300 MHz LOW
PASS FILTER