Using an FFT is probably counter productive. One cycle of 400 Hz is 2.5 ms so your 5 ms "tone" comprises just two cycles! It's computationally much easier to time "zero" crossings (with a modest amount of hysteresis) and that is likely to work pretty well for fairly clean signals. By the time you have to start digging into the noise to retrieve the signal things get a whole lot trickier.

Note that a 5 ms dot time represents 240 words per minute. More achievable speeds are less than 1/10th of that. For test purposes around 5 words per minute with a Farnsworth speed of around 12 wpm is fairly typical.

DWIM is Perl's answer to Gödel

In reply to Re^2: Morse code via sound card input by GrandFather
in thread Morse code via sound card input by aristotle73

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