RE: Difference between FM and PCM
A PPM system can refresh the data every 20 milliseconds or less, depending on the number of channels being transmitted and the time of the pulses. My system in 9 channel mode with all channels at centre 1.5ms is refreshing every 18 - 19 ms or thereabouts. In 12 channel mode it refreshes approx every 20ms if all channels are at centre. Compare that to the Futaba 9Z which is 8 proportional channels and a 1-bit channel, at 28.5ms. It is only the new 14MZ that gets PCM down into PPM times.
H