This is another great David Dixon filter design. It is a very clean and precise filter that also doubles as an excellent sine VCO.
It responds very well to FM and the small size makes it a nice choice for smaller system.
low pass (LPF) 2-pole, high pass (HPF) 2-pole and bandpass outputs (BPF) 1-pole.
FM1 input acts as 1V/Oct when full CW. Tracks very well over 4+ octaves
FM2 input has a bipolar attenuator
At full Q you get very low distortion sinewaves with a range of 2Hz to 20Khz