Also called a Lissajous. Used to determine the phase of microphone set-ups, an X/Y function shows phase patterns on an oscilloscope. A mixer’s left output channel is connected to the X (vertical) input on the scope; the right output channel is connected to the Y (horizontal) input. If these two channels are panned center and are in- phase, they will show up on the scope as a diagonal line that moves up and to the right. If they are out-of-phase, the diagonal line will move down and to the right.