This is a strange mixture of a VCO and a switched capacitor filter based on the filter presented by Jan Hall, as presented in Electronotes EN92 P14-15, which was in turn based on an idea in a 1974 issue of Electronic Design on a Biquart (twice the order) filter.
If you are after something different, this fits the bill. After all, how many filters have a sync input?

STATUS: built

Soundsample:
Bi-N-Tic used as VCO with MFOS 12db LP controlled by ADSR...