I have seen many spectrum analyzers with the warning on the RF input port: “!!! Avoid electrostatic discharge and DC voltage !!!”.
Out of precaution I always connected my signal source with a DC block but now I find the DC block filters my signal too much.
The signal comes from a line driver, there should generally be no DC voltage but I can’t completely guarantee that.
Since I have seen this multiple times I assume that this is something generic.
I understand that excessive ESD might be bad ... but DC voltage?
Does anyone know the reason for it and how seriously to take the DC voltage?
I mean, some amount of DC voltage (uVs) may always present.
Am I too over cautious? Is it safe to have a low DC voltage, say +/-1V on the signal?