would anyone know how to add a dds function generator to this jacobs ladder circuit?

http://www.edaboard.com/thread268393.html

would an optocoupler be required?

this is the freq generator I have

http://www.ebay.com/itm/new-DDS-Function-Signal-Generator-Module-Sine-Square-Sawtooth-Triangle-Wave-9V-/330917638551

still no progress on how to add it to jacobs ladder circuit, but on oscilliscope the waveforms look good
it goes up to 8mhz but no sweep function