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Thread: PXA noise figure measurement - swept RF and Swep LO on up converter?


Permlink Replies: 4 - Pages: 1 - Last Post: Jul 26, 2012 1:31 PM Last Post By: Dr_joel Threads: [ Previous | Next ]
midam

Posts: 21
Registered: 04/17/11
PXA noise figure measurement - swept RF and Swep LO on up converter?
Posted: Jun 12, 2012 5:57 PM
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Hi,
I'm currently playing around with our new PXAs especially with noise figure measurement mode.
Traditionaly, we measured our up converter noise figure to plot Noise figure vs. RF (of course this is output frequency of DUT. It will be IF in PXA speak.)
When I tried to do same measurement with PXA, I noticed that DUT set up in PXA does not allow to sweep LO and RF (IF in PXA speak) at the same time. I wonder if there is any reason for that or it is something that can be implemented in the future via firmware upgrade.
Thanks.
tabbott


Posts: 1,483
Registered: 07/24/09
Re: PXA noise figure measurement - swept RF and Swep LO on up converter?
Posted: Jun 19, 2012 4:31 PM   in response to: midam in response to: midam
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Hi -

We need more information.

When you say “Traditionally we measured our upconverter noise figure…” What instrument did you use to traditionally do this? How did you set up this instrument?

For the PXA measurement, in the N9069A Noise Figure mode, I would suspect you would do something like:
Mode Setup
DUT Setup
On the setup screen, in the DUT field, use pull down and select Upconv.
In the LO Freq Mode: select Swept
Freq Mode: should be Swept
Now you can set the start and stop frequencies of the RF and Start and Stop frequencies of the LO.

I don’t understand what you mean by “(IF in PXA speak)”.

Regards -
midam

Posts: 21
Registered: 04/17/11
Re: PXA noise figure measurement - swept RF and Swep LO on up converter?
Posted: Jun 25, 2012 6:07 PM   in response to: tabbott in response to: tabbott
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Hi Tabbott,

It would have been better if I could explain clearer. The simplfied version of question would be,

Why PXA cannot sweep both LO and DUT output frequency at the same time while fixing DUT input frequency when it is in upconverter noise figure measurement mode?

I copy and pasted some paragraphs from one of the PXA app note to explain what I was meaning by 'PXA speak'.

‘Downconverter’ means that the output frequency, (IF) is lower than the input, (RF).
‘Upconverter’ means that the output frequency, (IF) is higher than the input (RF).
NOTE This is the convention used in this analyzer. Some engineering terms use reversed terms for upconverters


Thanks
tabbott


Posts: 1,483
Registered: 07/24/09
Re: PXA noise figure measurement - swept RF and Swep LO on up converter?
Posted: Jul 10, 2012 10:13 AM   in response to: midam in response to: midam
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Hi -

At this time the Noise Figure application only supports measuring a fixed IF when the DUT is set to upconverter.
The DUT LO can be swept, but the application does not tune the spectrum analyzer to allow a “swept” IF measurement.

Due to your feedback, we will consider such an enhancement in the future.

Thanks for explaining how you would like to perform your measurement.

Regards -
Dr_joel


Posts: 2,731
Registered: 12/01/05
Re: PXA noise figure measurement - swept RF and Swep LO on up converter?
Posted: Jul 26, 2012 1:31 PM   in response to: tabbott in response to: tabbott
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Just FYI: PNA-X supports NF measurements for up or down converters with swept or fixed Inputs, Outputs, or LOs.

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