3-4 Displayed Average Noise Level (DANL) Chapter 3 — Spectrum Analyzer Verification
3-6 PN: 10580-00324 Rev. N S412E MM
3-4 Displayed Average Noise Level (DANL)
The following test is used to verify the Displayed Average Noise Level (DANL) of the spectrum analyzer in the
S412E. This test is performed using the RMS detection mode.
Equipment Required
• 50 Ohm Termination, Anritsu Model 28N50-2
Procedure
1. Connect the 50 Ohm Termination to the RF In connector of the S412E.
2. Press the On/Off key to turn on the S412E.
3. Press the Shift key and then the Mode (9) key. Use the rotary knob to highlight Spectrum Analyzer and
then press the Enter key to switch to Spectrum Analyzer mode.
4. Preset the S412E by pressing the Shift key, then the Preset (1) key, then the Preset button on the
touchscreen.
5. Press the Amplitude submenu button.
6. Touch the Detection submenu button and then the RMS/AVG submenu button.
DANL Test with Preamp Off
7. Touch the Amplitude button on the touchscreen main menu and set the Reference Level to –20 dBm.
8. Touch the Atten Lvl submenu button and set to 0dB.
9. Make sure that the Pre Amp On/Off submenu button is in the Off position. If the preamp is on, then touch
the Pre Amp On/Off submenu button to turn it off.
10. Touch the Freq main menu button and set the Start Freq to 10 MHz.
11. Set the Stop Freq to 1.6 GHz.
12. Touch the BW main menu button and set the RBW to 100 kHz.
13. Touch the VBW submenu button and set to 1kHz.
14.
Wait until one sweep is completed.
15. Touch the Marker main menu button and then the Peak Search submenu button.
16. Record the Marker 1 amplitude reading into the 100 kHz RBW Measured Value column in Table A-5,
“Spectrum Analyzer DANL with Preamp Off” on page A-3.
17. Repeat Step 10 through Step 16 for other frequency settings in Table A-5, if Option 6 is installed.
18. For each measured 100 kHz RBW value in Table A-5, normalize it to 10 Hz RBW value by subtracting
40 dB from the 100 kHz RBW measured value.
For example, if the marker shows a value of –100 dBm at 100 kHz RBW, the calculated value at
10 Hz RBW is –140 dBm (–100 dBm – 40 dB = –140 dBm).
19. Enter the calculated values into the 10 Hz RBW Calculated Value column in Table A-5.
20. Verify that the calculated value is less than or equal to the value in the Specification column in
Table A-5.
Note Before continuing, allow a 30 minute warm up period for the internal circuitry to stabilize.
Note
The noise floor consists of totally random signals whereas a spur is a fixed spike of varying amplitude
that is always visible.
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