Gating simply turns the output signal on and off for preset durations, which is adjustable in the Spooky2 settings. One example would be 4Hz (four times a second), which is the default setting. The rate (speed) of the Gate is half the Refresh Rate, which is adjustable in the Advanced menu. Therefore 8 entered as the Refresh Rate will produce a 4Hz Gate.
Some rifers feel that pathogens can become too accustomed to frequencies and then adapt in ways to overcome the effect of the signal. With the Gate pulsing on and off, the theory is that this signal variance prevents this from happening.