simply circuit is this correct?
please tell me your answer. thank you readed my writes.
Hello Song,
Active filters which are comprised of resistors, capacitors and op amps are available with different typologies. Some invert the applied signal from input to output, and others that don't.
An active filter topology that is a non-inverting filter is the Sallen-Key (SK) filter, while an inverting filter topology is the Multiple-Feedback (MFB) filter. Both of these typologies are available with TI's Webench Filter Designer software. That software can be used to synthesize low-pass, high-pass, band-pass and band-reject filters. Also, there are other filter typologies involving multiple op amps such as the universal active filter (UAF) that may be set up as either an inverting, or non-inverting filter. That typology is not included in the Webench Filter Designer selections, but is covered in many filter handbooks.
Here is a TI resource that provides in-depth information regarding the Sallen-Key active filter:
Even if a filter typology does invert, two filter sections can be cascaded, one after the other. The net result is two inversion is the equivalent of a non-inversion.
If you would like to to experiment with the Webench Filter Designer software here is a link:
Regards, Thomas
PA - Linear Applications Engineering
