Agilent Technologies E1401-90493 37. Displayed Average Noise Level: Agilent E4404B and E4405B

316 Chapter 2

Performance Verification Tests

37. Displayed Average Noise Level: Agilent E4404B and E4405B

37. Displayed Average Noise Level: Agilent

This performance test measures the displayed average noise level

(DANL) within the frequency range specified. The analyzer input is

terminated in its characteristic impedance. If the analyzer is also

equipped with a tracking generator (Option 1DN), the tracking

generator is also terminated in its characteristic impedance and set for

maximum leveled output power.

The test tunes the analyzer frequency across the band and uses the

marker to locate the frequency with the highest response. It then reads

the average noise in zero span using the minimum resolution

bandwidth (RBW) specified for the analyzer. Analyzers having Option

1DN (Tracking Generator) installed are tested in a 1 kHz RBW.

Analyzers having Option 1DR (Narrow Bandwidths) installed have a

minimum RBW of 100 Hz or 10 Hz. Even though analyzers having

Option 1D5 (High Stability Frequency Reference) and firmware

revision A.08.00 or later installed have a minimum RBW of 1 Hz, DANL

for these analyzers is specified and tested with a 10 Hz RBW.

To reduce measurement uncertainty due to input attenuator switching

and resolution bandwidth switching, a reference level offset is added.

The 50 MHz alignment signal is used as the amplitude reference for

determining the amount of offset required. The offset is removed at the

end of the test by pressing instrument preset.

The related adjustment for this procedure is “Frequency Response.”

Equipment Required

Termination, 50 Ω, Type-N (m) (2 required for Option 1DN)

Cable, BNC

Adapter, Type-N (m) to BNC (f)

Procedure

1. Connect the AMPTD REF OUT to the 50 Ω Input using a BNC cable

and adapter as shown in Figure 2-55.