Back in 1978, I designed and built my first VCO's that were even close to being half way decent. I had very little to go on. The internet was as far as I was concerned at least, non existant, never even heard of electronotes, Hal Chamberlins book was still a few years off, did not know any body else that was doing the same thing. It was an "ok" design. Had I known a few things back then, it could have probably actually been pretty good. I still have them. When I have the time, I am going to rework one and see if I can improve it. Don't ask me why I came up with that flip flop comparator. I can barely remember designing it, let alone the reason for it. The bigest problem the design had was that despite the temperature controlled 3046, there was still enough scale drift to be obnoxious. For those who are interested, here is the PDF file (redrawn recently from old sketches). By the way, save all of your doodles. 20 years from now, you will be glad you did. I was.