We have an application that requires a remote photodiode. The signal on the photodiode is low frequency analog (500 Hz sawtooth ramp) where linearity and noise on the signal is very important. We now use 2 op amps, one as a current to voltage converter (photodiode pre amp photovoltaic mode) and then a
second op amp for ac coupling the output from the first stage.
This output is used as an input for our ADC on our embedded computer - and then the signal is analyzed.
We have an application where the photodiode wil be remotely operated - up to 1 km from the ADC on our embedded computer.
The ADC has single ended inputs as well as differential.
How do we transmit (without noise pick up and distortion) the sawtooth waveform (+/- 12 VDC max levels) to the ADC?