Hi All,
I am controlling the tune voltage of an oscillator with a 16-bit PWM DAC out from Arduino (from the Lars DIY GPSDO project).
My oscillator needs a smaller tuning range than 0-5V, probably 1-3V or less would be fine. The current tune voltage is about 2.1V. I figured I can wire the DAC out to a 10k trimpot (simulated R1-R4) and use the center tap to the tune pin to increase effective DAC resolution.
Is there an equally easy way to improve noise and temperature stability? I was wondering if a 2.5V voltage reference could be easily used. I probably won't consider anything too complex, including op amps, etc.