I have an AD8421 (instrumentation amplifier); it has two pins to connect a resistor Rg that sets the gain --- G = 1 + 9.9k / Rg. For example, a 100 ohms resistor produces a gain G = 1 + (9900 ohms / 100 ohms) = 1 + 99 = 100.
I need the amplifier to have a lower gain at DC; to avoid additional stages or even a passive filter after the output, I wonder if I could use an R-C network where Rg is supposed to go, so that the "gain resistor" varies with frequency. In particular, what about placing the following:
With this, I get a gain of 10 at DC, and 100 at high frequencies, with transition being from approx. 1.6Hz to 16Hz.
Sounds like in theory it should work; is there any reason why it might not work in practice? Any experience out there with this or similar setups?