Use the uncertainty calculator we can get uncertainty curves, one of these curves is the 'dynamic accuracy' curve. I want to know what this curve indicates , and how can we get it.

Thanks a lot!

Thanks a lot!

Use the uncertainty calculator we can get uncertainty curves, one of these curves is the 'dynamic accuracy' curve. I want to know what this curve indicates , and how can we get it.

Thanks a lot!

Thanks a lot!

- Thanks very much for your detailed explanation.

Now, I see what "dynamic accuracy" is, but I still don't know how we measure the dynamic accuracy, in another word, how to get the "dynamic accuracy curve" for a specific VNA?

For millimeter network analyzer, for example, E8363B+N5260A+millimeter model, what's its dynamic accuracy?

Can I find the specification somewhere?

Afsi,

Thanks for a good overall explaination. I have just one clarification. Noise is not included as part of the dynamic accuracy specification in the sense that if you change your average factor or IF bandwidth the dynamic accuracy curve will not change. Since dynamic accuracy is a specification that is tested the noise effects of the verification test are reflected in the curve (as well as the other measurement uncertainties of the verification test). The net result is that the dynamic accuracy should be thought of as a specification that includes the linearity and compression but not the noise. The uncertainty calculator includes dynamic accuracy and combines it with the other error terms--including noise--to provide estimates for measurement uncertainty.

â€œDynamic accuracy is a measure of the receiverâ€™s performance as a function of the incident power level (relative linearity) and has an effect on the uncertainty of a gain measurement. This is because the receiver detects a different power level between calibration and measurement.

The effects of dynamic accuracy on a gain measurement are negligible as long as the network analyzer is operating below the specified 0.1 dB compression level.

The dynamic accuracy chart, as you've seen, is of measurement uncertainty versus power level. So if you tested an amplifier with 30 dB of gain, calibrated at an input power level of -40 dBm, you're adding less than 0.1 (~0.07) dB of measurement uncertainty to the gain measurement due to dynamic accuracy. As you can see on the chart, if you calibrate at -40 dBm input power, the lowest point in the graph occurs at -40 dBm. If you calibrate at -20 dBm, the lowest point is at -20 dBm.

The left side of the curve (higher-power levels) is dominated by compression. The right side by noise. The key is to manage your input/calibration power level such that you operate in the "relatively flat part" of the curve and avoid the two ends.

Remember that on many network analyzers, you can avoid compression (of the internal samplers or mixers) by utilizing the internal receiver attenuators. If your analyzer doesn't have internal receiver attenuators, you can add them externally. Just pay attention to where you add the external attenuators.

Iâ€™ve also attached an old 8510 paper on measurement uncertainty. Please note that the values in the 8510 paper refer to the 8510, and not the new PNAs.

Afsi