Hello, Thanks to all for your replies and suggesting especially Brooke, Bruce and Pete.
I am already using the Stanford technique with the 1 kHz output. That's how I get 2 x 10E-12/sec accuracy. Using this technique, the accuracy should be 7.9 uHz at 10 MHz (7.9E-13). But I don't reliably achieve this. I reliably get 20 uHz, sometimes 10 uHz and I do have resolution to parts in 10E-13, but the last digit isn't reliable. Brooke do you do better than me here with this technique? I see you publish results with accuracy better than I can achieve, I was wondering how you do it. I think the answer from Bruce identifies my problem. I need to take more care with my measurement techniques If it was easy, people wouldn't charge $20 - 50k for a box that dies it well. Thanks all again Martyn _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.