subsea hydraulic emitter..digital control?

My company produces a hydraulic transducer for subsea low frequency high power signalling applications. It is in essence two opposed pistons in a bass drum shaped housing driven by a linear servovalve powered by a variable displacement hydraulic pump. The pistons push out the centers of the drum sides, which retract on their own due to their own stiffness and ambient pressure. The design is all analog, and we would like to modernize it with digital circuitry to knock down the electronic noise. We would also like to add some telemetry features, such as a hours of operation logger, oil quality monitor, and heat sensors.

This system does not need to exert a known force or position or velocity, but rather needs to amplify/convert a complex signal into strong low frequency vibrations. What sort of digital motion control system(s) would be of benefit to a system like this?

The motion controller can generate sine waves multiple sine waves. It has a programming language call structured text that is kind of like Pascal and common in PLC controls.
position(t):=Amplitude1sin(2PIFrequency1t)+Amplitude2sin(2PIFrequency2t)+Amplitude3sin(2PIFrequency3t)+…+offset

It would be good to know the nature of the waves or signal being generated. The RMC has been used in other wave making applications where many wave forms were superimposed to generate the resulting wave. This may be handy for increasing the band width.

The RMC also has a sine wave function that simply generates sinusoidal motion. Normally this function is used for test systems as it makes sweeping frequencies smoothly either linearly or logarithmically very easy. This would be good if you are simply trying to detect two frequencies. The same function also allows one to change the amplitude smoothly on-the-fly but I can’t see how AM would be useful.

Finally we have cam tables that can be updated on-the-fly so that just about any arbitrary signal can be generated.