The receiver receives a signal that has a modulated pulse train on a carrier wave. Wait do I have to explain what that is too??? Anyway this pulse train consists of a signal pulse to start the information then a pulse to tell the receiver where each servo is centered at. Then the receiver gets this information and decodes it and then sends it to each servo. This is were clock frequency, decoding and other things can be different. All it takes is a little difference in a RCL cicuit and a pulse can be just a tad later than it's supposed to be, these are very short distances and you will notice on the servo a very tiny change in pulse decoding. You'd have to see all this on an oscilloscope for it to make sense.