78 N9069C Noise Figure Measurement Guide
Measurement Related Tasks and Concepts
Setting the Signal Analyzer to Make a Measurement
Using Loss Compensation
You can configure the noise figure measurement application to compensate for
losses due to cabling and connectors, and those due to temperature effects
that occur in the measurement setup. These can be between the Noise Source
and the DUT (
Before DUT
), or between the DUT and the analyzer input
(
After DUT
), or both. Loss compensation can be set either by specifying a
single, fixed loss value, which gets applied at all frequencies, or using various
loss values, specified in a table, applied across the frequency span. In the table
mode, linearly interpolated values are used between each table entry.
Any device that causes loss will also generate excess noise, and this excess
noise is proportional to the absolute temperature of the device causing the
loss. You can compensate for this extra noise by specifying the temperature of
the device causing the loss. This temperature dependent compensation is
applied at all frequencies.
Examples where Loss Compensation is applied
This is important in cases such as:
— Amplifiers with waveguide input, where a lossy waveguide-to-coax adapter
is needed.
— Transistors, where input and output tuners are required.
— Non-50
Ω
converters (such as TV tuners and amplifiers) where matching
pads or transformers are required.
— Compensation for fixed attenuators used to improve SWR.
— Double sideband measurement modification (of receivers and mixers) to
approximate single sideband results.
5.
Press
Select Highlighted Source as DUT LO
.
6.
On the Select dialog, press
Ext LO Setup
.
7.
Press
DUT LO Setup
.
.
8.
In the
LO Settings
area of the dialog,
set the
parameters such as LO Power, Min Freq and Max Freq as
needed
:
The LO frequency in
MEAS SETUP
,
DUT
Setup & Calibration...
should be set within
the range of Min Freq and Max Freq values.
Step
Notes
Summary of Contents for CXA N9000B
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