Is there a good way to convert a square wave between 50hz and 5khz to a reasonably neat sine wave?
If you first convert the square wave to a triangle wave, check out this link......
www.analogzone.com/den7.pdf
Here is another approach....... http://mypeoplepc.com/members/scottnoanh/sitebuildercontent/sitebuilderfiles/th_sine_shape.jpg