How to pull up the amplitude of the HRS / PPM signal from a Futaba RX? [Archive]

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micke_b

Sep 28, 2009, 03:23 PM

Hi, Im trying to read of the PPM / HRS signal from a Futaba RX. But the amplitude of the signal is only 0.5 volts? Is this correct? How can I pull it up? 5 volt amplitude vould be great. :confused:

feegie park

Sep 29, 2009, 08:25 AM

0.5 on a scope?

If it was a 0.5 rectangular waveform and to a connector,it is likely to be open collector,needing an external pull up.
If that works,feeding a digital transistor(or bipolar NPN & two integral 47k's) with additional pull up would make an acceptable D.C. interface lead.

Next time,stick on a 220k to any sensible voltage and retest before contemplating anything else.:rolleyes: