f/v converter

[Jonas Karlsson]

Hello!
I am thinking about building a frequency to voltage converter and use it to control the synthesizer i'm building. The f/v converter should use a squarewave (from my D110) at the input and create one voltage that is proportional to the frequency, and one that is proportional to the amplitude. 

Is this a good idea? This way I don't have to build (or buy) a MIDI to CV converter. 

The v/f part is easy to design, but the problem with it is that the output of it is exponential, so I have to build an exp. to lin. converter. Is there an easy way to do this?

I really would appreciate any comments and ideas on this subject.

Jonas Karlsson