MusicMiK who has brought us these excellent videos on his synthesizer DIY projects wrote in to let us know that he has created a page on the exponential converter. You can find that page and more here."The nature often has a logarithmic or exponential behaviour, this also applies to the human reception of volume levels and frequencies. So for the human ear, musical intervals like octaves feel like linear, but in fact are exponential. One octave is the double frequency, two octaves are four times the frequency and so on. As it is easier to handle the control of pitch in a linear way (for example using a resistor divider chain in the keyboard to convert a constant current flowing through the resistors to a linear voltage depending on the key pressed), there must be something to convert the linear control to the exponential output, like the frequency of a VCO.
This is the job of the exponential converter, which is a term commonly used in electronic music instruments, whereas the term used in other technical areas usually is antilog amplifier, as it does the opposite of a logarithmic amplifier."
