Stereo bandpass filter


2007-07-01 3:03 pm

I am trying to tune my car and made an adapter cable from the factory knock sensor to a small stereo jack.

I sounds good but i would like to interfere a bandpass filter so i only hear the frequency i am interested in (in this example 6900-7200 Hz).

Can someone help me out here since circuit design is not my field? :)

I would not mind if it would also amplify the signal and gave me earphone output. (if there is a ready cheap solution, let me know).