Hi, I'm designing my own DDS board and using the AD9910 board as a reference.
I don't understand what R67 and R68 are needed for. Could I get some info?
Resistors R67 and R68 are used to connect the SYNC_OUTs of the AD9910 to its SYNC_INs. That is, the evaluation board is set as the master when used in synchronizing multiple devices as shown in this application note.