I am interested in characterising my lab equipment by testing the hmc661lc4b in dual rank configuration and compare the datasheet linearity with what I measure. I am especially interested in characterising this at higher sample rate >10GHz. I wish to achieve this by cascading 2 of the Hittite eval boards consisting the HMC661LC4B and provide them with 180 degree out of phase differential clocks. To get a good output, it is of utmost importance to align the 180 degree clocks properly. I am currently using a combination of a Balun and a phase delay unit to get the 2 clocks 180 degree out of phase. However, this does not seem to be giving be an accurate alignment of the clocks. Can you please suggest a better method for the clock alignment? Or is there a component that I should be particulary using to align my clocks?