how can I bulid a simple FSK demodulator with 1Mbps at least?

Answer 1

Here is a basic circuit (it's the last article of the group, at the bottom of the pdf file):
http://www.edn.com/contents/images/101101di.pdf

All you have to do to get it to run at 1 Mbps is change the inverter from that little NL27WZ14 to a 74AHC14, and change the values of the feedback components to make it oscillate faster (i.e. C2 = 100 pF).


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