[ebarker]

Get a pencil and paper and draw these waveforms:

Standard PWM waveforms, for simplicities sake, set the period to 1 ms
a) a 50% duty cycle square wave - this is the 'neutral' position, it is called square because it looks square
b) 90% on/ 10% off wave,
c) 10% on/ 90% off wave,


RC PWM waveforms.
If I remember right, the pulses can come as infrequently as 20 ms.
The width of the pulse varies between 1 to 2 ms, 1.5 ms being neutral.

So if you draw a nominal neutral RC PWM wave form, it could (but doesn't have to look exactly like this) look like a repeating waveform that is 1.5 ms on, 18.5 ms off. ( I may have my on/off logic sense inverted here so just flip it over)

That is WAY different than the neutral 50% square wave in (a) above.


Ed

PS - I just went and looked at the links for the waveform. If you read the paragraph above the waveforms it talks about the 20 ms. THe graph doesn't have the interpulse interval marked out. THe graph is a little misleading because it looks square'ish, but I can assure you that it isn't. Ask around and see if you can find someone with an oscilloscope and see if you can get them to help you 'see' these signals. Seeing is believing.



famous saying in engineering is "all you gotta do is......" then you run into reality.