AW: making LP filters into HP

[Christopher List]

>>             I guess what I'm really wondering is do state-variable
>>   models have to be designed from the ground up as state variable or can
>>   you "enhance" any LP filter to get a high pass response <<with>>
>>   adjustable Q?

> You can also get a HP response by switching each stage from
> LP to HP: For HP, use the capacitor of each stage as input.

Could you elaborate a little on this? What do you mean "as input"?

> By tapping a common 4pole LP after the 1st, 2nd or 3rd stage
> you get 6dB/12dB/18dB LP filter.

Yes, I've been playing with this, it is nice!

- Thanks,
Chris