we're trying to provide input to a microcontroller from an rc reciever that outputs a PWM signal, but we're having a lot of trouble with intereference. if we just turn on the reciever's power supply, the servos start trembling to the random signals the reciever picks up and if we connect the servos or reciever to the microcontroller supply, the output waveform seems stable, but unless we actually turn on the transmitter (rc control) the servos keep trembling and moving unpredictably. sometimes this goes on even with the transmitter on.
we've been told we need decoupling capacitors but we tried 0,3μF capacitors between every power and ground we could find in the circuit, including the transmitter, servos and micrcontroller and yet nothing changed at all. we positioned the transmitter away from the microcontroller breadboard, which reduced idle interference, but once we connect even the white control wires of the servos or the blind reciever channel (we've sliced a connector cable up so it can connect to the microcontroller) the power supply of the microcontroller ruins everything, including the input signal it reads (causing it to output a totally random PWM, which is not what we programmed it for - it seems to be doing its job ok though, because under other conditions it samples signals fine).
how can we get rid of all the interference and get clean PWM signals everywhere?