Input Attenuation Switching Uncertainty Performance Test

This test measures the step accuracy of the PSA input attenuator at 50 MHz. A signal source is connected to the PSA through the 10 dB and 1 dB precision step attenuators. The PSA input attenuator is varied from 0 dB to 70 dB while the external attenuator is switched from 70 dB to 0 dB. The step loss of the external attenuator is characterized to ± .03 dB. Therefore the PSA Input Attenuator Switching Uncertainty can be calculated through RF substitution. The PSA mixer level is maintained at a constant level, thus eliminating scale fidelity error. Fixed attenuators are placed in the signal path in order to maintain a consistent match between the step attenuators and the PSA.

If the PSA is outfitted with Option B7J (Digital Demod Hardware), the test is performed once again on the internal Electronic Attenuator

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 Equipment Calibration Data section in the N7800A 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 Number

Signal Source

PSG Models
(see equipment list)

1 dB Step Attenuator

8494G Option 001, H50

10 dB Step Attenuator

8496G Option 001, H50

Attenuator Driver

11713E

Attenuator Interconnect Kit

11716A 

6 dB Fixed Attenuator

8491A Option 006, H33 

10 dB Fixed Attenuator

8491A Option 010, H33

BNC Cable

8120-2582 

Type-N Cable

11500C 

Type-N (f) to 3.5 mm (f) adapter
(for E4440A/43A/45A Option BAB)

1250-1745

2.4 mm (f) to Type-N (f) adapter
(for E4446A/47A/48A)

11903B  

Connection Setup