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unsuitable for a musical instrument. So, instead we invented our own unique, patented circuit in which the
keyboard voltage (which is the VCO control voltage) itself doubles for each one octave increase in pitch.
EG control is also simplified in the Korg system.
For the trigger signal (also called a "gate" signal) that is used to start EG operation, Korg uses a simple
switch and 2p phone plug connection instead of the special plugs and switches needed for the "
of system.
The "
" type of system used by Korg also makes it easy to use microcomputers to control the
synthesizer.
Specific differences between the two systems
The graph in Figure 1 below 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. In other words, a one volt
rise in voltage produces a one octave rise in pitch (OCT/V system).
In contrast, the curved line on the graph is the control voltage from the keyboard of a Korg or Yamaha
synthesizer in which VCO frequency is proportional to voltage (Hz/V system). Note that the voltage
doubles for each octave rise in pitch. The difference between the trigger (gate) signals of the two systems
is clearest if you think of the trigger as a switch. In the lower diagram below is shown the Korg system (
) of switching on EG operation (initiating operation), and the means by which the other system (
) accomplishes the same thing. In the (
switch to the EG. In the (
required.
- logarithmic versus linear cv systems
- trigger types
3) Features and Functions
- guide to 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 a Korg or Yamaha synthesizer 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 a Korg synthesizer by means of a unit that uses the OCT/V system.
Adding Amp:
This can be used for mixing control voltage signals or sound signals.
When not plugged into an outlet, the adding amp operates as if -5V and +5V inputs were connected to its
two channels. Therefore, depending on how you set up your equipment, you can also use the adding
amp as a voltage supply, or to shift a control voltage to a higher or lower value, and so forth.
) system, only two lines are needed to connect the
) system, either three lines, or the addition of a battery to the switch is
" type
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