I am trying to measure the noise figure of an active DUT that should have a gain of around -30 dB and a noise figure of 30-40 dB.
I have trouble getting accurate results from the methods I have tried. I have an E4440A and have tried using the Noise Figure measurement personality with a 346C Noise Source. I have also tried the using a low noise figure amp after the DUT to boost the noise floor and calculated the noise figure using the noise floor of the combination and the gain of the low noise amp and DUT. From what I have read I have too much loss and/or too much noise to get a good repeatable measurement.
I also have read about cold-source measurements but this seems daunting to do manually on potentially several hundred units a month.
Anyone have suggestions on how I can get a good repeatable measurement without too much difficulty?
I have trouble getting accurate results from the methods I have tried. I have an E4440A and have tried using the Noise Figure measurement personality with a 346C Noise Source. I have also tried the using a low noise figure amp after the DUT to boost the noise floor and calculated the noise figure using the noise floor of the combination and the gain of the low noise amp and DUT. From what I have read I have too much loss and/or too much noise to get a good repeatable measurement.
I also have read about cold-source measurements but this seems daunting to do manually on potentially several hundred units a month.
Anyone have suggestions on how I can get a good repeatable measurement without too much difficulty?
DUT match may be the issue. I recommend performing this measurement using isolators. That way if you do have a DUT match issue, the isolator will help and your NF measurements will become much more realistic and stable. If the isolators help, you can measure their insertion loss and compensate for that as before DUT loss or after DUT loss. When performing the noise source calibration make sure none of the devices are connected. You want to perform the noise source cal with the noise source connected directly to the RF input of the analyzer.
Regards -
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