Keysight NFA X-Series Getting Started and Troubleshooting Guide 21
Quick Start
Using the U7227-Series USB Preamplifiers in Noise Figure Measurements
Using the U7227-Series USB Preamplifiers in Noise Figure
Measurements
The U7227-Series USB Preamplifiers turn the overall X-Series noise figure
analyzers into better noise figure analyzers by reducing instrument noise
figure. Reducing instrument noise figure is necessary when the device under
test (DUT) is lossy or has low gain. This is because the instrument noise figure
contributes more to the final measurement uncertainty when the gain of the
DUT is low.
shows how the measurement uncertainty of a typical
noise figure measurement depends on the DUT gain and instrument noise
figure. The data is derived using the Uncertainty Calculator in the N9069C
noise figure measurement application. It can be seen that the measurement
uncertainty increases when the DUT gain is low and instrument noise figure is
high. In optimal noise figure measurements, these regions should be avoided.
Therefore adding preamplifier correction data is not necessary.
Figure 1-1
3-D Plot of Measurement Uncertainty versus DUT Gain and Instrument Noise
Figure (DUT Noise Figure: 3 dB)
This section first introduces how to connect the U7227-Series USB
Preamplifier to the signal analyzer and then provides a rough guide about
using the USB preamplifier and the internal preamplifier inside the signal
analyzer.
“Initial Connection to the Signal Analyzer” on page 22
“Guide for Using U7227-Series USB Preamplifier and the Internal Preamplifier
Summary of Contents for NFA X-Series
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