Thanks to all who helped me understand One final question would a 50MHz 8 digit with accuracy of +/- 1Hz possible or would +/- 10Hz be more realalistic I am not including the normal +/- one count and clock accuracy If anyone wants to help me explore these possibilites I have all the required hardware to test and verify the software, (HCD Research frequency standard, AF and RF Marconi signal generators. with digital syncroniser and various accurate frequency counters) It's writing the program that's above me So if anyone wants to write the software contact me by private email Peter Cousens email: peter@cousens.her.forthnet.gr phone: + 3081 324450, 380534 snailmail: Folia, Agia Fotini, Karteros, Heraklion Crete, Greece.