the intiminator rely on inertial state of the valve body to momentarily open up a by-pass circuit to relieve the damping pressure when the wheel hit bump causing the stanchion to move rapidly (relatively speaking, compare to slower chasis movement)
At that rapid movement instant, the intiminator valve lags behind in its movement compare to the rest of the system and as a result expose a in build pressure relief circuit to soften the damping rate for that instant.
It is the lagging reaction of the intiminator which provides the pressure relief.
The spring used in the intiminator determines how much lagging is needed to open up the relief circuit.
If you ever dismantle the intiminator, it becomes a clearer as how it works than words can describe
The above deals with fast fork movement or wheel movement as Ricor likes to call.
In terms slower fork movement or chassis movement, it uses shim to deal to determine the damping.
Racetech emulator uses the increase in damping pressure when a wheel hits a sharp bump to open up a cap to relieve pressure.
RT uses low velocity bypass orifices to control low velocity fork movement.
Since i had the opportunity to test a professionally well setup RT emulator for a rider of a similar weight and similar riding style and my own tuned intiminator, the following observations were made:
1) we both agreed, all else being equal intiminator deals with brake dive a noticeably better.
2) tiny bumps are better absorbed by RT Emulator - although later further tuning close the gap for the intiminator - but i still give it to Emulator
3) mid size bump are about the same at the same given speed
4) big bump is better on the intiminator ( up to the limit of travel), i think - he is silent on that one
5) we each think our own system is slightly better so cant agree on that one
we both have good respect for the other system
At the end of the day, both tool are capable of doing a good job - if it doesnt work for out of the box, it's time to tune it