Hi, all
I am now using the PXA N9030A to do IP3 measurement. (combined with two SGs, power combiner, attenuator,etc)
Before measuring my DUT, I adjust the input attenuator of N9030A (mechanical attenuator). IMD signal level should be decreasing, noise level should be increasing, with the increase of input attenuator. However, my result is like the following:
input ATT(dB) IMD lvl (dBm)
0 121.7
2 124.4
4 130.4
6 128.4
8 126.1
10 135.3
12 140
14 134.4
16 126.6
18 126.9
20 126.7
At the same time, when do the same measurement using the old model PSA E4440A, IMD and noise floor do increase and decrease with input ATT being increased.
Setting,
both analyzers are in
RBW=1Hz,
span=100Hz,
measuring frequency is around 400MHz.
Any comments are welcome. Thank you very much!
Yours,
Yiliu
Edited by: wangyiliu on Apr 22, 2013 9:16 AM
I am now using the PXA N9030A to do IP3 measurement. (combined with two SGs, power combiner, attenuator,etc)
Before measuring my DUT, I adjust the input attenuator of N9030A (mechanical attenuator). IMD signal level should be decreasing, noise level should be increasing, with the increase of input attenuator. However, my result is like the following:
input ATT(dB) IMD lvl (dBm)
0 121.7
2 124.4
4 130.4
6 128.4
8 126.1
10 135.3
12 140
14 134.4
16 126.6
18 126.9
20 126.7
At the same time, when do the same measurement using the old model PSA E4440A, IMD and noise floor do increase and decrease with input ATT being increased.
Setting,
both analyzers are in
RBW=1Hz,
span=100Hz,
measuring frequency is around 400MHz.
Any comments are welcome. Thank you very much!
Yours,
Yiliu
Edited by: wangyiliu on Apr 22, 2013 9:16 AM
The PXA is implemented with third-order distortion nulling: an active circuit recreates and cancels out the third-order products. At some frequencies, the circuit can add undesired signals of significance at some attenuation settings. Nevertheless, you should still be able to realize better performance with less uncertainty than PSA, provided you select a sufficient amount of attenuation. There is a password-protected setting under the service menu (available to our service centers) for which it is possible to turn off Intermod Nulling to observe the difference in performance caused by IM Nulling. For more information contact your local Agilent call center.
Thank you -