Do ESCs expect PWM or PPM signals?

Hey there

I am a bit confused about whether ESCs expect PWM or PPM signals. I have read multiple times that they expect PPM signals but I wonder how that's possible because PPM signals are always of the same width but I send signals of different widths depending on the speed I want. So is it PWM signals that the ESCs are expecting?

ESCs, in common with servos, expect a PWM signal

The confusion arises because RC systems send multiple servo signals in a stream of PPM data

If one servo only for every Arduino out you must use pwm with 20mSec period and from 1 to 2 mSec of positive pulse duration, if use radio transmitter the old stream RC ppm protocol provides for the transmission in sequence, always in the period of 20mSec up to 8 impulses to drive 8 servos, it will be the receiver that will separate the 8 impulses from the stream and send each impulse to its corresponding servo