I have a photodetector with differential outputs that are each 50-ohm terminated. When I connect one output to the oscilloscope to look at the signal, I see a higher signal amplitude with higher channel impedance on the oscilloscope. According to my very basic understanding, maximum power transfer should occur when the impedance is matched. Could you help me understand what is happening here?
The pictures are taken from my scope, and you can see the amplitude of the signal when the termination is 1-Mohm is more than double what I get when the termination is 50-ohm. The cable connection to is as follows:
PD --> 50-ohm SMA --> SMA-BNC adapter --> 50-ohm BNC --> Scope