Effective DANL Functional Test

This test applies to the following models:

• N9038A Option NFE
• N9038B Option NFE

• N9048B Option NF2

For MXE N9038A and N9038B, this test is called Effective DANL Option NFE. For PXE N9048B, this test is called Effective DANL.

Option NFE/NF2 provides noise corrections which will allow the EMI receiver to measure signals close to the noise. The corrections will essentially compensate for the known conversion loss of the EMI receiver RF front-end.

The noise floor improvement is inferred from amplitude measurements made on a signal close to the noise floor. The test is actually three measurements that are performed at each test frequency. The choice of test frequency was center of the band offset by 100 MHz times Pi. This frequency offset was done to avoid measuring residuals.

Measurement 1 (M1) — This is a DANL measurement made in a 300 kHz resolution bandwidth. The goal of this measurement is to baseline the noise of the DUT. The test signal amplitude will be placed approximately 5 dB above the measured noise floor.

Measurement 2 (M2) — The test signal amplitude is calculated from the DANL measurement. This step measures the amplitude of the test signal in the 30 Hz resolution bandwidth. The 30 Hz resolution bandwidth will provide a 40 dB improvement in SNR. The goal of this measurement is to baseline the true amplitude of the test signal.

Measurement 3 (M3) — The resolution bandwidth is set to 300 kHz and the amplitude of the signal (plus noise) is measured with the noise corrections set to On. The 300 kHz resolution bandwidth causes the SNR to be around 5 dB. The amplitude difference relative to the M2 measurement is the noise contribution.

The "effective noise, Neff" can be calculated from the results of these three measurements:

M1 = Uncorrected Noise (in watts) = N

M2 = Amplitude of signal with high SNR (in watts) = A

M3 = Amplitude of signal with low SNR (in watts) = A + Neff

Neff = A – (A + Neff)

Neff = M2 – M3

Let’s state this as a ratio because then we can easily calculate the relative improvement in terms of dB:

Noise Improvement (Linear) = Neff/N = (M2-M3)/M1

Noise Improvement (dB) = 10 x LOG(Neff/N) = 10 x LOG [(M2-M3)/M1]

The Effective DANL can be calculated by the following equation:

Effective DANL (dBm/Hz) = Uncorrected Noise (300 kHz RBW) + Noise Improvement (dB) + 1 Hz RBW Normalization

Effective DANL (dBm/Hz) = 10 x LOG(M1/.001) + 10 x LOG [(M2-M3)/M1] + 10 x LOG (300000)

Where: 10 x LOG (30000) normalizes the result to a 1 Hz resolution bandwidth.

For Option NFE, refer to the Effective DANL Adjustment.

For N9048B PXE

If the Effective DANL test should fail, Option NF2 requires a manual noise floor characterization. To do this,

• For PXE without WF1, press System > Alignments > Advanced > Characterize Noise Floor

• For PXE with WF1, press System > Alignments > Advanced >Characterize EMI Receiver Noise Floor

Click here for troubleshooting.

Required Test Equipment

Test Equipment	Model Number1
Microwave Signal Generator #1	PSG Models (see equipment list)
BNC Cable	8120-1840
Cable, 3.5 mm coaxial For Options 503, 508 and 526	11500E
Cable, 2.4 mm coaxial For Option 544	8120-6164
Adapter, 3.5 mm (f) to 3.5 mm (f) Required for Options 503/508/526 when using a 3.5 mm source. For Option C35	83059B
Adapter, Type-N (m) to 3.5 mm (f) For Options 503, 508 and 526	1250-1744
Adapter, Type-N (m) to 2.4 mm (f) For Option 544	11903D
Adapter, 2.4 mm (f) to 2.4 mm (f) For Option 544	11900B
Adapter, 2.4 mm (f) to 3.5 mm (f) Required for Options 503/508/526 when using a 2.4 mm source.	11901B

Refer to the main Required Equipment table for a list of alternative models.

Connection Setups

Effective DANL Test Setup (RF Input 1)