[Date Prev][Date Next]   [Thread Prev][Thread Next]   [Date Index][Thread Index][Author Index]

Re:sample rate

>Bell Labs researcher Harry Nyquist develops Sampling Theory. It 
>states provides that if a signal is sampled at twice its nominal 
>highest frequency, the samples will contain all of the information 
>in the original signal.

Which is clearly not true :-)
There's no way to keep the phase information for a signal sampled
at only twice it's frequency.
Only the amplitude.

Or, alternatively, as Jon explained,
a 22050Hz signal is only captured by 44100Hz sampling if the sampling
happens to occur at the peaks and troughs of the signal, and not
at the zero crossing points.

I've never seen that in a text book, which causes me some concern,
but it's very obvious.

I guess that the Nyquist Theorum is misquoted somewhat here
(and generally).

andy butler