The main problem is that no IC manufacturers have made spice models available for LVDS. There are IBIS models which I tried to convert into spice models via many softwares, but the spice model it generates is too complicated to be able to import or create a model in Multisim or Orcad/Pspice as it generates many .subckt files. Kindly suggest me if there is any other way to provide LO signals apart from LVDS driver. Thanking you.