nyquist theorem

[iamallthings]

today, i learned about something called the "Nyquist Theorem", which states:

"if a function x(t) contains no frequencies higher than B hertz, it is completely determined by giving its ordinates at a series of points spaced 1/(2B) seconds apart."

if i'm to understand Nyquist's Theorem correctly, what this means for you is that, in the process of digital recording, the sample rate must be TWICE the HIGHEST audio frequency to be converted, or: any frequency whose value is higher than your sample rate multiplied by two will NOT be captured to the digital recorder.

science!

Nyquist Theorem

[RandoRando]

ive heard any sample rate higher than 44khz or whatever the standard is, is kind of overkill as most common stereos dont go above (x) hz, or am i reading it wrong..

[slothrop]

today, i learned about something called the "Nyquist Theorem", which states:

"if a function x(t) contains no frequencies higher than B hertz, it is completely determined by giving its ordinates at a series of points spaced 1/(2B) seconds apart."

if i'm to understand Nyquist's Theorem correctly, what this means for you is that, in the process of digital recording, the sample rate must be TWICE the HIGHEST audio frequency to be converted, or: any frequency whose value is higher than your sample rate multiplied by two will NOT be captured to the digital recorder.

More to the point, it must be twice the highest audio frequency that you NEED to capture. There might be all sorts of stuff going on above that, but if only bats can hear it, it doesn't matter.

Perfect hearing for a human tops out at approx 22kHz, so if all you're going to do with something is record it and play it back, then 44kHz will capture everything that you can actually hear.

[-[2]DAY_-]

wel of course... heh when u think about it thats very straightforward. If u'r tryna capture vibrations that are faster than twice ur samplerate, the recorder wouldn't b fast enough to hear the wavecycle