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PNA-X - +30dBm compression limit

Question asked by mirek on Oct 22, 2010
Latest reply on Oct 28, 2010 by Dr_joel
I have some problem with high power amplifier measurement on PNA-X.
The problem is that the Pout Compression stop exactly at +30dBm, were the expected P1dB is around 35dBm. I know that PNA-X have function to set the power limits, however my limit are set to +100dBm and the system stop at +30dBm .

At +30dBm from my DUT, I should not have more then +10dBm to Port 2 (I have 20dB high power safety attenuator after DUT).
It looks like the system does not recognize what is the real power applied to the B receiver.

Where are the receiver safety limit set on PNA-X and how I can change them?

By the way the limits setting form are kind of confusing. It looks like it setting only sources limits. We need separate sources limit and receiver’s limits. Source limit define safety limit for DUT. Receiver limits should define safety limits for each of the receiver (reference, reflection and thru measure receiver).

Can the Agilent implement scalar compression measurement on PNA-X?
When you perform high power compression over wide band, it is not simple to find suitable coupler that can operate at high power. Simpler approach is to put high power safety attenuator, and calibrate out the loss. Such attenuator probably will provide much better marching load then any coupler. Proper real (not virtual) load matching is one most important characteristic during compression measurement.  

There should be option for vector calibration for full forward calibration (source reflection and thru). In such case high attenuation can be used on input port.

I think that, the full two port cal combine with very high attenuation (20 or 30dB) that I used do not look like particularly valid approach for measurement.

I also have couple question to usage of vector calibration function and measurement during compression measurement:
1. Does input reflection is measured during power sweep iteration?
2. Does output reflection is measured during power sweep iteration?
(I think it called hot reflection measurement with reverse signal with small frequency offset).
2. Does the power correction value are applied base on measured reflection during power sweep?