You mean a signal expressed as presure?
Just an idea, don't know if it is sensible:
I would use a small volume vessel with a very small hole against the pressure as an analogue of capacitor against voltage. Resistance against flow would be a small pipe.
I would look up the circuitry for integrating, differentiating and filter circuits, and build the analogue.
However it would be much easier and punctual to convert the pressure into voltage, and use the usual signal processing tools.