No it's a pulse. Spot stitch is something completely different.

Just as with any pulse you have your pulse width (time on) and frequency controls.
Instead of pulsing amps, you are pulsing volts with MIG between to levels rapidly at a minimum of 20 hz up to 200 hz.
The pulse time on adjusts the time spent in the high voltage part of the pulse verses the low voltage part.

This is designed to pulse rapidly between spray and globular transfer, allowing the voltage to dip briefly down into the globular range long enough to cool off but desposit little if any metal. This in theory allows you to weld out of position with the unit.

The "synergic" mig is preprogrammed with various settings of the pulse width and frequency for any given setting. All it does is take away some of the science behind the pulse and give the operator a preset point of operation. Most of these migs have background menus that allow manual setting of the pulse as well, as in the Miller 350P.