Tamas Rudnai wrote :

> erm, strange PWM as the period is at 50Hz
> (around 20ms) but the duty cycle is between 1-2ms.

That is not strange at all, It's a plain standard RC-servo
signal !!

> What you can do basically is that see if the signal
> is in between 1-2ms, that's no problem....

Yes, the "pulse", correct. The timing of the pulse lenght
is what's important. The 20 ms interval is not (as important).

> I do not know why but it seems that 20ms is not
> always kept...

And why do you think that it should ? The function of
the servo is not dependant on the intervall beeing
"exactly" 20 ms. It can probably be 15-25 ms without
a real problem.

> My basic problem is to determine if the signal is so
> bad it has to go to a safe position and wait until
> good signal can be received.

Are you designing a "modell-saver" ?

> Interestingly when I switch off the thransmitter it knows
> trait away that there is no signal so shuts down the
> system after a couple of moments.

What is "it" and "system" ?
The RC-receiver should see that there is no 27 (or 40)
Mhz carrier and stopp producing pulses on it''s servo
connectors. It that what you are saying ?

> It is very interesting to me as I could still see
> strange duty cycles when the transmitter is off.

So the receiver still produces pulses ? Funny...

> Maybe there is a good method for dealing with such a problem,
> but I thought it is very specific, that't why did not want to
> bother you with the details.

What you have descibed *now* seems to be very important
to understand your problem...

Jan-Erik.



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