Display Scale Fidelity Performance Test

This test applies to the following models:

This test verifies the scale fidelity (linearity) of the analyzer at 50 MHz by comparing it to an external precision attenuator. As the external attenuation is increased in steps, the change in power level indicated by the analyzer's display-marker is monitored. This test is performed in two parts so the step attenuator uncertainties are minimized.

Part 1 —  Input Mixer level of –21 dBm to –35 dBm

The analyzer input attenuator is set to 10 dB in zero-span mode.  The source is set to +10 dBm and the external composite attenuator is set to 19 dB.  The resulting  –25 dBm signal is measured by the analyzer and recorded as the reference.  The analyzer input power is then varied between –11 dBm and –17 dBm (–21 dBm to –27 dBm at the mixer) by switching the external attenuator.

Part 2 —  Input Mixer level of –35 dBm to –85 dBm

The analyzer input attenuator is set to 10 dB in zero-span mode. The source is set to -10 dBm and the external composite attenuator is set to 19 dB. The resulting -25 dBm signal is measured by the analyzer and recorded as the reference. The input power is then varied between the -25 dBm and -75 dBm (-35 dBm to -85 dBm at the mixer) by switching the external attenuator.

At signals below -85 dBm, noise (not linearity) becomes the dominant error. Noise averaging would increase test times, so these levels are not measured.

 

This test requires step attenuator calibration data to obtain valid results. Make sure you enter the calibration data for the step attenuators that you're using. Please refer to the Enter Equipment Calibration Data section in the TME help for details on how to enter this data. You must enter the data for the following columns to obtain valid results: Attn(dB), Uncert(dB) and ReflSize.

 

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Required Test Equipment

Test Equipment

Recommended

Model Number

Microwave Signal Generator #1

PSG Models
(see equipment list)

1 dB Step Attenuator

8494G Option 001, H50 

10 dB Step Attenuator

8496G Option 001, H50 

Attenuator Driver

11713B

Attenuator Interconnect Kit

11716A 

3 dB Fixed Attenuator

8491A Option 003, H33

6 dB Fixed Attenuator

8491A Option 006, H33

10 dB Fixed Attenuator

8491A Option 010, H33

Type-N Cable
(2 required)

11500C 

BNC Cable

8120-2582 

3.5 mm (f) to Type-N (f) adapter
(for 3.5 mm source)

1250-1745

2.4 mm (f) to Type-N (f) adapter
(for 2.4 mm source)

11903B

Connection Setups

In the following setups, cables are designated as solid lines and direct connections are designated as dashed lines.

Display Scale Fidelity Test Setup, Part 1

 

Display Scale Fidelity Test Setup, Part 2