>Nyquist says, you need to filter at less than half the sample
>frequency before you sample the signal.
>  
>
Not exactly,
he said sample frequency should be at least half the bandwidth.
So e.g. if you know (apriori) that your frequency is between 1000 and 
1100 Hz,
it's enough to sample with 200 Hz.

Stef

>  
>
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