noise figure measurement

nice new feature.

Any reason why this is not enabled on the SA44B ?

Some observations and suggestions using a BB60C :
– I can store and reuse the ENR table of the noise source. I have not found a way to reuse the measurement from steps 1/4 and 2/4 ( calib of noise source ). I think it is not usefull to store this but there should be a way to reuse it without always reconnecting noise source and DUT.
– measurement mostly come out in the expected range and close to the real value, but there are also values totally out of range.
That is from the noisy environment. I guess it is running to fast or averaging is set to low.
– it would be a great impovement if you implement a feature that switches the sync/trig connector on the backside. The signal could be used to switch the noise source on and off.
– if the noise source can be switched by the analyser the next consequent step would be to have an auto mode ( not only single )
– while I have the ENR table for my noise source I am wondering if it is possible to use a noise source without knowing the ENR

Thanks

Volker

Hi Volker,

Thanks for the feedback.

We have disabled the measurement for the SA44/124 devices due to their lack of hardware image rejection. The wideband noise source aliases in at all points in the measurement affecting the results. We have not determined if we will address this.

We intend to revisit this measurement in the future. Reusing the noise source measurements (step 1/2) is something we plan on adding. We agree that it would be beneficial to not need to perform this step for each measurement.

We have also considered how we would perform more automation with the noise source. The trigger idea is good.

We can review the noisy values you are seeing. With some more testing we might be able to reproduce and deal with these. Can you provide any configuration information for the measurements on which you saw this issue? I will include this in my notes.

Can you clarify your last question?

Thanks again for the feedback. This will be very useful for future development. We are happy this measurement has been useful for you. Hopefully we can make it better in future revisions.

Regards,
Andrew

Hi Andrew,

thanks for the information about the SA44/124.

I played around with the new NF function and compared this with the values I get from an Eaton 2075. I have a HP 346B and a selfmade noise source that are reproducing realistic values. In the frequency range of about 800 to 1000 MHz I am always getting values to high. The rest is really close to what is expected. I will invest some more time next week and have a closer look.

For my last question:
There was a interesting article here

https://www.mwrf.com/technologies/test-measurement-analyzers/article/21845669/measure-noise-without-a-calibrated-source

I have not tried this, but the steps to use this measurement method are very close to yours.

Best,

Volker

Hi Andrew,

I spent a little more time then I wanted. The function is working nicely and is producing results that are close to what the Eaton is measuring. I have seen peeks in NF at about 850MHz, but this is only with one DUT and I have no idea why…

Exporting the complete hot/cold data could probably be also a nice feature.

An application note of how the measurement is done could also be very helpfull. Especially what is done with the input attenuator and the preamp. That also leads to the question what NF the BB60C has. I have not found any informations about this.

One more automation step could be evaluating the optimal RefLevel, but the first one is definately temporary storing the noise source
cal to skip steps 1 and 2 of the four steps when you want to repeat the measurement

Thanks for this feature.

Volker

[Andrew]

Thanks for the follow up information Volker.

Did you see the Spike manual section on Noise Figure? We have the equations we use for the measurement. We will be writing a white paper for this soon.

I agree that measuring the noise source once is the best first step for automation.

NF of the BB60C will vary slightly per device, but is roughly the DANL of the instrument + 174. You can find the DANL specs in the product manual.

• This reply was modified 3 years, 8 months ago by Andrew.

Shame on me, I had a wrong manual.

Compliments to you for intuitive implementing of this feature. I will check again with “4.12.5 Limitations” in mind

Thanks for the improvement in 3.5.13.
Good Job.

[Author]

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