I don't have a sensor to mesure the position, but when i put closely my ear I can listening some shake, like a heart beat, and when i use the osciloscope I can see the variation of the duty cicle of the PWM period. I think that 1 degree isn't imporant, but I need that the servo stays in the same position to control the position of something, if it moves i can check correctly the thing that i am observing.
Thanks for help!