Keysight NFA Series Noise Figure Analyzers Service Guide 493
Functional Tests
Displayed Average Noise Level (DANL)
AMPTD, –70, dBm
AMPTD, Attenuation, Mech Atten, 0, dB
BW, Res BW, 1, kHz
BW, Video BW, 100, Hz
Meas Setup, Avg/Hold, Number, 20, Enter
Trace, Trace Average
Single/Cont until single sweep is selected.
4. Press Restart, then wait for Average/Hold to display 20/20.
5. Press Display, Meas Display, then press Display Line, On.
6. Rotate the knob and set the display line at the average amplitude of the
displayed noise floor by visual inspection.
7. Confirm that the measurement is performed on the analyzer noise floor
and not on a residual response within the displayed 10 kHz span.
8. Enter the value of the display line as the Measured Average Noise Level at
10 MHz column in Table 17-2 on page 492.
9. Normalize the measured value to a 1 Hz BW by adding –30 dB to the
measured value.
10.Enter the normalized value of the displayed average noise level in
Table 17-2 on page 492.
11.The value of the normalized displayed average noise should be less than
the specification value.
12.Change the analyzer center frequency to the next value listed in
Table 17-2 on page 492. Press: FREQ, Center Frequency, [Table 2-1
Value], GHz
13.Repeat step 4 through step 12 to fill in the remainder of Table 17-2 on
page 492 for your analyzer frequency range.
Ignore the residual response if one appears when taking the measurement.
The –30 dB value is added because the formula used to calculate the
value of the noise power in a 1 Hz BW when measured with a 1 kHz BW is:
Normalized Noise = 10 Log (BW 2/BW 1) where BW 2 is the 1 kHz
BW we measure and BW 1 is 1 Hz BW to which we want to
normalize.
Therefore, 10 Log (1000) = 30 dB, so the noise floor will be 30 dB
lower in a 1 Hz BW.
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