variable center frequency bandpass filter

Dan Dobbins

Other Parts Discussed in Thread: LMF100

Hello, I need a bandpass filter design that has a voltage controlled variable center frequency from about 40Hz to about 10,000Hz with a high Q. Does such a filter exist? If it can't be voltage controlled then could it be controlled with just one pot?

I had thought to use the LMF100 switched capacitor filter but I need it with through hole pins and could only find it as a surface mount.

I need 3 of these filters so I hope to find an IC or a simple circuit to use.

Thanks!

over 11 years ago

0 Don Dapkus over 11 years ago

TI__Guru**** 189401 points

Hi, Dan,

If you like the LMF100, you could use an interface board like this to convert it to a DIP-style package.

-d2

0 Dan Dobbins over 11 years ago in reply to Don Dapkus

Prodigy 20 points

Thanks Don, I might try that. Are there easily adjustable bandpass filters other than switched capacitor? I'm trying to model the first 4 formants of the human voice. I suppose very wide band notch filters would work also but it seems like the circuit would be harder to tune that way.

0 Don Dapkus over 11 years ago in reply to Dan Dobbins

TI__Guru**** 189401 points

Hi, Dan,

Unfortunately, I'm not that familiar with doing this type of processing in the analog domain. You might try posting a question in op amp forum to see if anyone there has better suggestions on how to accomplish what you're trying to do.

-d2

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variable center frequency bandpass filter