AnsweredAssumed Answered

Source Power and gain error with DIQ and SMC

Question asked by cgantz2000 on Dec 3, 2015
Latest reply on Dec 7, 2015 by cgantz2000
Using fw 10.20.

I'm coming up with some errors in gain and port power after doing SMC and DIQ cals. The attached .csa and .png files are subsets of what I'm trying to measure, with the settings done manually so my program doesn't come into the picture.

If you look at the png file, windows 1 and 3 were done using one CalAll, window 2 was done using a standard SMC cal wizard. I set port power to -10dBm during the cal and for the measurement, and I have about 15 dB cable loss. The two SMC measurements show IPwr at about -7.2dBm, and gain at about -16dB. I've measured the gain manually with a power meter, and that seems to agree with the -16dB, and the power out also agrees. So the measured power out is about 2.7 dB higher than the set port power.

For the DIQ measurement, the IPwrF1 measurement agrees with the set port power, but the measured power is about -7.3dBm, the same as the SMC measured powers. And the DIQ gain is 2.9dB higher than the SMC gains, about the same error as the SMC power measurements.

This all worked about a week ago, before I moved the test setup. I don't know if there was some obscure setting that was changed, but I haven't been able to find it. Thanks for any help you can give.