I know the topic is immensely broad but I dont have the practical knowledge on the following issue:
Let's say I have a very long like 1km BNC cable carrying DC signal around 1V analog voltage signal coming from a transducer. And let's say the BNC goes all the way straight to an ADC with 100 Meg-ohm input impedance at the end. If the measurement should be very accurate, do we need to buffer this signal?
BNC cable even 1km long has very very low resistance comparing to ADC's huge input impedance. Theoretically form this point I would think one wouldn't need a buffer.
But how would that be implemented in practice for 1V DC level and 10mV DC?