I've been designing & prototyping a GPSDO for some time as a learning tool. I'm designing it in modules to be interconnected and trying to avoid ground loop issues since there will be multiple connections per board.
So I'm wrapping up the OCXO module now. It consists of a big
IsoTemp 134-10 sine wave oscillator, a
KO4BB isolation amplifier, and a
MiniCircuits RF splitter to send one copy of the signal off to the distribution amplifier and another copy off to the control board (squarer, PLL, etc.).
My question is whether I should keep the 1:1 transformers I added to each of the splitter outputs to ensure the two downstream modules don't get a different ground potential on the signal since everything will share power grounds. Or does it even matter? The distribution amp is a single ended input with the shield connected to the chassis/system ground. But the squarer on the PLL board has a transformer input. I have enough gain in the isolation amp to overcome the transformer losses, but are the 1:1 outputs just silly?
(Please pardon the ugly board; I haven't cleaned up the silk screen yet.)