Display Scale Fidelity Performance Test

This test verifies the scale fidelity (linearity) of the EMI receiver 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 DUT'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 –85 dBm

The EMI receiver 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 DUT and recorded as the reference.  The DUT input power is then varied between –11 dBm and –75 dBm (–21 dBm to –85 dBm at the mixer) by switching the external attenuator.

Part 2 —  Input Mixer level of –35 dBm to –16 dBm

The EMI receiver 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 26 dB. The resulting –25 dBm signal is measured by the DUT and recorded as the reference. The input power is then varied between the –25 dBm and –6 dBm (–35 dBm to –16 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

Model Number1

Microwave Signal Generator #1

PSG Models
(see equipment list)

Attenuator, 10 dB Fixed

8491A Option 010, H33

Attenuator, 6 dB Fixed

8491A Option 006, H33 

Attenuator, 3 dB Fixed

8491A Option 003, H33

Attenuator, 10 dB Step

8496G Option 001, H50 

Attenuator, 1 dB Step

8494G Option 001, H50 

Attenuator Driver

11713B

Attenuator Interconnect Kit

11716A 

Cable, Type-N

  • 2 required

11500C 

Cable, BNC

8120-1840 

Viking Cable (attenuator control)

8120-2703

Adapter, 3.5 mm (f) to Type-N (f)

  • For 3.5 mm source

1250-1745

Adapter, 2.4 mm (f) to Type-N (f)

  • For 2.4 mm source
  • For Option 544

11903B
  1. Refer to the main Required Equipment table for a list of alternative models.

Connection Setups

Display Scale Fidelity Test Setup, Part 1

 

Display Scale Fidelity Test Setup, Part 2