Re: sample rate

[Bill Fox <billyfox@soundscapes.us>]

Tom Combs wrote:

> I thought the Nyquist theorem is all about reconstructing a signal 
> once sampled.  A signal is not reconstructed by simply "connecting the 
> dots", it is reconstructed by passing it through a low pass filter.  
> If you pass a sawtooth, triangle, square, or any other variety of 
> periodic signal with frequency f through a low pass filter whose 
> passband is perfectly flat up until frequency f, and then perfectly 0 
> beyond f, then what comes out is a pure sine wave of frequency f - 
> that's because squares, triangles and whatnot all contain harmonics in 
> addition to the pure sine wave that dictates its fundamental frequency.
>  
> A signal sampled at twice the Nyquist frequency can be perfectly 
> reconstructed in a world of perfect filters and perfect sampling devices.

Right on!

Cheers,

Bill