The SLEW-13 is a slew generator which smoothes out the transitions of an incoming signal.
The rate knob changes the transition time from instant to 10 seconds per volt.
Slew Generator output.
The SLEW-13 is typically used by connecting a 1v/oct signal into the input socket and connecting an oscillator to the output socket. This effect creates the portamento or glide pitch effect available on most synthesizers.