OK this is a bit of a silly question. (But what the heck better than thawing tundra.)
I want to split an error signal into HF and LF parts. I've wired this up as an RC filter, taking DC (LF) from the cap., and using an instrument amp to read the voltage across the resistor.
Error in----+---. | | R +--> Instrument R -->High Freq out. R +--> Amp.(Ground ref.) | | +---+ +---Opamp buffer--> DC out | C C C | GND
R = 300 to 10 k ohm. (300 is about most the opamp driving it can supply.) C = 2.2 uF. (About 10 Hz cross-over frequency at the low end.)
Is there anything wrong with this approach?
George H.