Re: [Autopilot] how to amplify the PPM signal

[Achim W. <awa...@gm...>]

(Second attempt to send this mail. The mail I sent on Friday seemingly has
not reached the list, maybe due to server problems. Please ignore if you
receive this the second time.)

> Got 2 options for you.
> 
...
> 2. If it's not the above, then you have a 'normal' analog output 
> (Rload = inside RX circuit), then you have to use a voltage-comparator 
> LM311.
> These are used to convert a non-TTL signal to the common TTL levels of 
> 0 - 5 Volts.

I take option 2 ;-). It looks like the RX uses op-amps internally to process
the signal and at some point the "raw" signal is put out for further use. So
I have to do the same that is done internally to amplify the signal as input
for the 4017 decade counter.

> 
> P.S. It may help to draw us the PPM output circuit, will explain a 
> lot.
> 
> Regards
> Coert

I understand you would like to see the RX intern circuit. I am not yet able
to draw a schema but took pictures of the RX. You can see the signal and
circuit on my home page at http://www.voidpointer.de/tmp/ppm.html. It has a
TA 75339F in it which is similar to the LM 339 D according to internet
research. If so, then using a LM 339 externally should give me the desired
result. The local electronics store might have either the LM 311 or the 339
and give me some hints about the circuit.

Thank you for the quick answer, Achim.