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Debugging tone decoder(567) for FSK needed

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Member level 4
Jul 31, 2009
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567 tone decoder

I have been using LMC567 foe FSK demodulation.
Is it feasible enough.
An FSK modulated wave is applied to pin 3 as i/p. R and C are selected to the freq. value which is the same value of the freq. of the modulated signal when the digital precedor(counterpart) of it had a low.
thus I will get a low when the freq is detected and when not (where the digitally high equivalent of freq is as the i/p) i'll get a high as the LMC o/p.
Thus the original signal is traced or demodulated.

To start with, simply decting the freq and gettin respective o/p, I did connections the following way.
pin 1 and 2 connected to ground via a 1nF capacitor.
pin 3 as input.
pin 4 as +Vcc
pin 5 had a 10K resister then connected to pin 6
pin 6 had the other end of 10K resistor and a capacitor of 0.1uF going to grnd.
pin 7 Grnd.
pin 8 O/p, A pull up resistor of 10K, Across measurment going to CRO

Now thr RC combination gives me Center freq-Fo=903 Hz

And 1kHz comes in its detectable pass band.

When to its i/p I give other than 1KHz I get High output (5V)
But when i give to its i/p 1kHz, I get a high freq Square wave in o/p.(On CRO)

What should be the i/p as in- square wave/sine/triangular wave???
When the i/p lies in its passband freq of adjusted center freq. What should I expect as a output. Should it be low level voltage, or when i'm gettin a high freq square signal is proper.

PLZ PLZ Guide and help.. In V much need.... Want to submit the project quickly.

Take care

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