But how is that isolated? On its schematic, it’s clear it’s not galvanically isolated.
there is no isolation, it has direct connection between input and output ground
Hello: Unclear your objective:
Isolate scope input 1 M from mains etc?
Pass DC...HF and convert 75 Ohm ><50 Ohm?
The Mini Circuits part is a Zo match with DC bias link eg for cable TV use. The transformer wthin has a LF point determined by the core, area and number of turns.
This should be designated for example as 10 MHz...3 GHz 75><50 Ohm match with DC bias link"
It is NOT a DC-3 GHz device despite the specs!
Suggest to read the Tektronix Circuits Concepts book "Oscilloscope Probe Circuits Concepts" to understand the different scope input and probe options.
https://w140.com/tekwiki/images/6/62/062-1146-00.pdfIf you can define precisely the system freq,min max (eg DC-100 MHz?) and isolation needed the forum can assit you better,
Bon Chance,
Jon