This is my quadrature generator for use in phasing SSB radio.
It's two PCB's concept of Stefan DL5MGD http://www.dl5mgd.de/dds/AD9951.htm and built by Krzysztof SQ8Z.
My work is Atmel AVR ATMega32 based controller.
Idea is simple, the two AD9951's have one clock source and receive same frequency settings in same time.
Only the "data" wire is split which gives me the ability to initialize them separately. One goes with SINe function and other with COSine (Control Function Register 1 of AD9951 and 0x00001000 bit)
In current software (below - WinAVR C project) there's only frequency selection, but I plan to use two pots on ADC inputs of ATmega to control precise phase and amplitude of DDS.
Schematics not included (was to simple - wasn't drawn), but pinout is in main source file. Of course You can always write me an email for it.
Below there is an output of DDS. Amplitude difference it's not by DDSes but my oscilloscope. SQ8Z made them well, altough they have problem with final amplifier that is generating even harmonics, 2f is only 11db below main peak! You can even see it on oscilloscope.