Posted here before that I dont think discs warp ! Ill add "usually"
Check your pads are not binding and that they are evenly worn, it could be a sign of sticking pads, they drag on the discs and deposit a layer of material that can cause juddering, but its usually makes the steering wheel wobble not the brake pedal to pulse.
My cure for my juddering brakes, and they were bad, was new pads, clean the calipers properly, then on an empty road do at least three hard stops from 50mph to zero, it cleans all the crud of the discs.
As has been said before, pads and discs are dirt cheap.
Mark