is it true that it just transmits the pulses? So how do the 3-channels work?
Could you upload an image of the measured signal, using an oscilloscope etc.?
Just dug out my notes made 10 years ago.
For sake of accuracy, the control signals are 'off' periods in the RF carrier coming from the transmitter.
The receiver converts these gaps into pulses. My transmitter was 4 channel. It broadcast an ANNOUNCE pulse followed by 4 more pulses. 50 frames per second.
The receiver breaks up the pulse train. It must handle as many channels as the transmitter sends (or maybe the receiver will simply ignore any leftover pulses).
It distributes a pulse to each servo. The width of the pulse tells the servo where to move to.
One channel is usually dedicated to motor throttle. Look for a stick on the transmitter that stays where you put it (rather than return to center like the others). The receiver sends this signal to the motor.
Each servo acts independently. Each servo's range of action must be properly adjusted for the aircraft to fly properly.
There are transmitters that 'mix' the stick inputs according to what kind of aircraft you're controlling. (V-tail, etc.)
It's up to the pilot on the ground to work the sticks right. To control an aircraft automatically will require a very intelligently programmed microcontroller.