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Author Topic: Default PPM polarity?  (Read 1934 times)

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Offline pheasant_plucker

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Default PPM polarity?
« on: January 10, 2017, 13:12:05 PM »
I have a DJT module fitted to my X12s for my V8FR receivers.
What polarity PPM do I need to set when I bind them?

Gerry
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Offline Phil_G

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Re: Default PPM polarity?
« Reply #1 on: January 10, 2017, 14:25:53 PM »
Either Gerry, Frsky modules are all edge-change triggered so the polarity doesnt matter at all.
On the emulation encoders I used to invert the PPM for JR style modules but theres no point, it makes no difference to a Frsky module.  The PPM pulse width is also non-critical (unlike Spektrum for example where it has to be 400uS)
Cheers
Phil

« Last Edit: January 10, 2017, 15:06:33 PM by Phil_G »

Offline pheasant_plucker

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Re: Default PPM polarity?
« Reply #2 on: January 10, 2017, 14:57:28 PM »
Thanks Phil, So your saying the receivers aren't bothered which polarity pulse they get?

GErry
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Offline Phil_G

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Re: Default PPM polarity?
« Reply #3 on: January 10, 2017, 15:04:42 PM »
The receivers dont see the PPM at all Gerry. PPM is just a means of conveying stick positions to the RF module input - from then on its all digital, ie packetised data, there is no PPM transmitted,
Thats why CPPM has the 'C',  to look at on a scope its an identical signal, but CPPM is 'combined' from channel data inside the receiver, not passed on from the transmitter in any way as it would be with a 35mhz set.
Cheers
Phil
« Last Edit: January 10, 2017, 15:09:17 PM by Phil_G »

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