convert Step/Dir signal from mach3 AKZ250 board (z axis or A axis ) to PWM

yes i agree with you guys on the timings of mach3, but the stepper motor doesn't know anything about synchronization.
when you tell it to turn, it turns. i want to increase the intensity of the laser in the same time i get the turn command.

i can control the increment and decrement in arduino to have a good intensity modulation.

i could be saying nonsense .

what do you suggest as alternative?!

i am sure there is workaround.

what about this post that i just found :

http://www.machsupport.com/forum/index.php/topic,12444.0.html