I am trying to create a phase sweeper at 31.4KHz(and constant 5V) for a small antenna array that consists 2 antennas. If I can create 2 signals with a frequency difference < 1Hz it's okay too(It will be nearly same) as long as I can control that difference because I need to change phase at a constant velocity which I can change. It's okay too if you can tell me how to do it with arduino or LPC1769(I have one) or with a PIC(I can always buy one!). I tried to do it with arduino and created phase shifts with resolution of 5 degrees. But unfortunately the maximum frequency I got was 172Hz! My last resource would probably be making a rc phase shift oscillator with an opamp which has 18 RC stages. But then I need to control it from arduino so it'll be a very big and complex circuit. Thanks!