I'm trying to come up with a filter or converter that takes a square wave input and outputs something closer to a sign wave (varying between ~1.9kHz and 2.1kHz). It can have some distortion, but I'm trying to eliminate the sharp leading and trailing edge. One option I'm pursuing is a bandpass filter (2 caps and 2 resistors), which looks to give a reasonable output, but still not quite as smooth as I'd like. I've also considered using a counter feeding a bank of resistors, but finding a method for it to start counting up with it hits 0 and down when it hits the high value might be more difficult.
Originally, I had used a wein-bridge oscillator with op-amps to make the sine wave, but due to the environment, EMI was a problem and it damped out the oscillations (even with ferrite beads and modest shielding). So I'd like to avoid using op-amps (since they are apparently sensitive to EMI) if possible.
Thanks in advance! Dave