492 Keysight NFA Series Noise Figure Analyzers Service Guide
Functional Tests
Displayed Average Noise Level (DANL)
Displayed Average Noise Level (DANL)
Test Limits (with 0 dB input attenuation)
See Table 17-2 for values.
The Displayed Average Noise Level (DANL) of the signal analyzer is measured
across a 10 kHz frequency span at several center frequencies. The analyzer
input is terminated into a 50 Ω load. A test is performed to assure the
measurement is not performed in the presence of a residual response. The
measurement is then averaged, and the result is normalized to a 1 Hz
bandwidth.
Figure 17-1 DANL Test Setup
Procedure
1. Configure the equipment as shown in Figure 17-1
2. Press MODE/MEAS. Select Spectrum Analyzer mode, Swept SA
measurement, Normal view. Press OK. Press Mode Preset on the analyzer.
3. Set up the signal analyzer by pressing:
FREQ, Center Frequency, 10, MHz
Input/Output, Input, RF Coupling, select DC
FREQ, Span, 10, kHz
Table 17-2 DANL Measurement Requirements
Item
Critical Specifications
(for this test)
Recommended
Keysight Model
Termination, 50
Ω Type-N (m)
a
Frequency: 10 MHz to 18 GHz 909A Option 012
Termination, 50
Ω 2.4 mm (f)
b
Frequency: 10 MHz to 50 GHz 85138B
a. For N8973B, 74B, 75B
b. For N8976B