The ED102 borrows heavily from the Korg MS-02â„¢ although it was developed independently of Korg Inc. Korg and MS-02 are the trademarks of Korg Inc. Among presently available music synthesizers, there are two different types of control system used for controlling devices such as the VCO (voltage controlled oscillator) and VCF (voltage controlled filter). These two systems been: Hertz/Volt (Hz/V) and Octave/Volt (Oct/V). The graph to the left shows the relationship between the VCO oscillator frequency (pitch) and the control voltage (keyboard output voltage). The straight line on the graph is from a synthesizer in which there is a one octave change for every one volt change in the control voltage (Oct/V). In contrast, the curved line on the graph is the control voltage from a synthesizer in which the VCO frequency is proportional to voltage (Hz/V system). To allow these systems to work together you will need a module like this ED102. The built-in, fully adjustable log amp and anti-log amp ensure complete system flexibility and compatibility between any presently voltage controlled synthesiser. The Hz/V system In the Hz/V system, the VCO oscillator frequency is proportional to the control voltage so that, for example, if the frequency of a VCO increases by 100Hz for every volt applied, then applying 1V, 2V and 3V to this VCO would generate 100Hz, 200Hz and 300Hz respectively. The Oct/V system In the Oct/V system the VCO oscillator frequency changes one octave for every one volt change in the control voltage so that, for example, 1V, 2V and 3V to a VCO would generate 200Hz, 400Hz and 800Hz respectively. Features and Functions Log Amp: This changes a Hz/V type keyboard CV (control voltage) output into an OCT/V type of CV. Use the Log Amp to change the control signal from, say, a Korg or Yamaha synthesiser into a signal you can use with another type of synthesizer. Antilog Amp: This changes an OCT/V type of keyboard CV output into a Hz/V type of CV. Use this Antilog Amp when you want to control, say, a Korg synthesiser by means of a unit that uses the OCT/V system.