I think you'll have to find a way to synchronize the startup ('reset')of all
the DDS's. If you don't, they'll all start clocking at different times. The
output doesn't come for some number of clock cycles later, depending on
what's loaded into the counters. Because of this, you'll have "phase lock"
but not "phase coincidence". Synchronizing DDS's is described by Analog
Devices in an appp-note on generating quadrature signals using 2 DDS chips.

Joe
W3JDR


wrote in message
oups.com...
Well actually, the project I had in mind was to take the 60 khz WWVB
signal and use diode harmonic multipliers to create a clock in the
gigahertz range. I would then use this clock as the input to a DDS
system. I could use the GPS to calculate lightspeed delay between
the VFO and the WWVB to determine compensating phase lag.

This could be good for synchronizing the transmit and receive ends of a
digital communication, improving the signal to noise ratio.

The Eternal Squire