I traced it in case anyone wants a schematic (also plz help verify just in case).
I also took the bandpass example Moritz provided as an invitation to add a switch to alternate LP/BP (S1) and make it a single circuit.
I was thinking about adding a LPF to a microcontroller project, but that means 5V single supply. Any chance I can make this circuit work with a virtual ground (Vref = V/2 with two resistors as voltage dividers) and, where should I replace GND with Vref in this one?
Im thinking R6, R11, IC2D and IC1C non inverting inputs.
Am I missing something?
Would it even work?
Do I need D1, D2 and D3 working with a single 5V rail and a 5V PWM from the microcontroller as the CV?
I also swapped TL074 for the LM324 as it already works in single supply.
Thanks!
PS: The FREQ pot goes from +V to -V, not +V to GND, sorry.