Good Evening..
I’ve got my QA403 Configured in Balanced/Differential Mode Via BNC to XLR cables. Right now I simply have the output (balanced) connected to the input (balanced). My question how to I get the same reading. I have the generator set at (IE +4DbU) When select the Gain In DB it reads 6.01. I can’t seem to figure out how to get a calibrated reading. It always seems to be off.
Hi @skipburrows, you are seeing the gain reported as 6 dB because you are connected in balanced mode. In balanced mode, the signal is twice that reported, because you are taking the complementary outputs and feeding them into the ADC.
Because there’s not a single-ended output on the QA403, the actual output level depends on how you have connected to the output. And so, if you are connected to the output balanced, you should right click on the dBV button:
And set your external output gain to 6.02 dB
And then, your generator settings will match the balanced output levels, and your gain calcs will be correctly reported too.
If then if you want to make an unbalanced measurement, you need to go back and change the external output gain to 0 dB.
