I wrote a bit of VHDL for generating inc/dec pulses from quadrature rotary encoders like the CTS Electrocomponents ones I bought from Digikey for a project I worked on recently. This debounce circuit ...

Experimenting with an HF oscillator, I needed to control the varactor diode voltage in precise increments over a 2V-10V range. A buffered potentiometer was the obvious choice, and connecting two pots ...