Dan :

I have had time finally to check your suggestion, and you are
completely right : reducing the amplitude of the signal
entering the 567 to less than 2 V, the pll locks the input signal
and I get the tone decoding signal (0V when the signal is caught).

Now I must check the consistency of the signal, that is, if I
can use it to measure distances.

Thanks for your help !

Joan

Dan Larson wrote :
>
>  Last time I used an LM567, I had problems when the signal to be
>  decoded had too much amplitude. Whenever my signal (70Khz from
>  an amplfied PIN diode receiving an IR signal) got over 400mV P-P
>  in amplitude, the decoder started going crazy. Only by reducing
>  the signal to less than 400mV or so did it behave. This then necessitated
>  adding a signal clamp or AGC stage before the LM567, but by then
>  I gave up and went with an IR receiver module instead because the
>  circuit components were going to take up too much space.
>
>  In your case, I would try reducing the amplitude of the signal
>  fed into the LM567.
>

--------------------------------------------------------------
     Joan Ilari                 e-mail : joan@ilari.org
     Barcelona                   www   : www.ilari.org
     Spain                      Voice  : +34 93 431 96 39

"I've seen things you people wouldn't believe. Attack ships on
 fire off the shoulder of Orion. I watched C-beams glitter in
 the dark near the Tannhauser gate. All those moments will be
 lost in time, like tears in rain. Time to die..."
                                               -Blade Runner-
---------------------------------------------------------------

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