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Hi,

I've come across an interesting conundrum.  I'm using the tone() function to, of course, generate a tone.  I've also made a 2nd order Sallen-Key filter to clean up the harmonics a bit and get a bit closer to a sinusoidal wave.  I've tested the filter against a square wave generator and it seemed to do the trick very well, however when I hook the filter up to the arduino tone generator, the filter output still remains a square.  The cutoff freq is set to about 50 Hz and the testing frequency is 200 Hz.  All Caps are 0.22 uF and Resistors are 15k.  Am I missing a key piece of knowledge in the arduino's tone generation?
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Post your circuit.
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Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
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Ah I figured it out, the arduino output was saturating the op amp.  How embarassing...
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