Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
This is a single transformer with a center tapped winding on one side. The four ports are the center tap to ground, the end of the windings to ground, and the other winding. You can observe that by symmetry, the coupling between the untapped winding and the center tap of the other winding is zero.