Watch the video for an brief explanation of marker pulse in incremental encoders.
Incremental encoders output a square wave when the shaft is turned. There may be several output channels, as shown in the video. The Z channel (also called the marker channel) emits 1 pulse per rotation.
This “marker pulse” may be a certain number of degrees of the electrical cycle or a certain number of degrees of the revolution of the shaft. The reason for the different widths of the marker is so that it’s easier for the controller to pick up the pulse.
This pulse is used a reference or home position in rotation or revolution of the shaft.