I am looking for ideas for an easily freqeuncy variable lowpass filter, ie adjustable with a single pot. Want to maintain a constant 6 db/oct rollof as the frequncy is adjusted.
One way that could work I think is a simple RL voltage divider where the L is a gyrator circuit. Effectively this is identical to using the standard graphic EQ circuit, remove the C of the "RLC string", and set for full cut. Although I guess this is actually a very deep shelving EQ, but would work for my purposes.
A state variable filter takes a dual gang pot to vary frequency (IIRC?) but that is a possibility.
Any other simple ways to do this? Switching capacitor size in an integrator circuit is another option, but that is not continuously variable.
One way that could work I think is a simple RL voltage divider where the L is a gyrator circuit. Effectively this is identical to using the standard graphic EQ circuit, remove the C of the "RLC string", and set for full cut. Although I guess this is actually a very deep shelving EQ, but would work for my purposes.
A state variable filter takes a dual gang pot to vary frequency (IIRC?) but that is a possibility.
Any other simple ways to do this? Switching capacitor size in an integrator circuit is another option, but that is not continuously variable.