I designed a bandpass filter with the TI filter designer tool but I initially designed with a gain of 40 dB. However, I'd like to reduce the gain to 20dB but I'm having issues doing trying to figure out which resistors to change for the gain ratio. It's supposedly a Sallen-Key Topology. My electronics knowledge is very basic and I'm mainly trying to design a pre-amplifier for a hydrophone to be passed on to an ADC but the gain on my output suffers from two issues:
- Amplitude of the AC signal is 7.8V pp but my ADC can only take up 3.3V.
- ADC is also unipolar but I have negative voltages in my signal for this I'm thinking of using a summing amplifier.
Can I adjust the gain by changing resistor values, or is it a bit more complicated than that?