BLM CYDONIA DUAL FILTER
BLM7200 DARPA project
Model: Cydonia Bi-phase Stereo VCF
width: 12hp
current: 83mA, -77mA
What does this module do?
The module has two filters, and two OTA-based VCAs. Most of the controls are setup to control both filters with one set of parameter knobs. There is a spread knob that separates the resonance peaks between both filters. You can get cool vocal and nasal filtering with careful adjustment. The filters self resonate. There is a trimmer for each filter which allows you to adjust how much feedback you want.
There is a fancy CMOS based logic control system to select the state variable outputs. DG412 modern analog switch is used internally. This analog switch is made for audio (-5v / +5). There is a 'reset' button to quickly go back to LP flavor.