[Bill Noble[_2_]]

"Steven Sullivan" wrote in message
...
Sonnova wrote:
On Fri, 21 Nov 2008 06:15:19 -0800, Steven Sullivan wrote
(in article ):

Kalman Rubinson wrote:
photograph.


If it takes up 3/4 of a spectrum, then that only means that the scale
of
the 'spectrum' has been absurdly expanded to ~100kHz.

Well, of course. Koschnike's point was that 192 KHz sampling has response
out
to 96KHz (half the sampling frequency). so, obviously, the DC-22KHz would
be
roughly 1/4 of a spectrum that goes to 100KHz.

Sorry, but what is the 'point' of making a point like that? All it is, is
an
entirely predictable confirmation of Shannon/Nyquist: your 'response'
will extend out
to just less than half of whatever your sample rate is. No one with a clue
would ever *expect* to see anything in spectral view beyond what the
Nyquist limit of 'response' dictates. So OF COURSE any spectral content
visible beyond 22 in 192 kHz-sampled audio, will be absent in a 44kHz
sampled version.


This shows that the LP faithfully preserves the HF content of the
master, while the CD does not.

snip-------

sounds like someone has a fundamental misunderstanding of sampled data
theory

if you are sampling a sine wave (or square wave) at a single frequency, so
long as your sample rate is 2X or greater than the fundamental, you will not
get ALIASING of the fundamental. This says nothing about distortion of
phase or waveform. If phase information is important, a significantly higher
sampling rate is needed - 10X is much more typical. A control system for a
large airplane, for example, had a roll off at 4 Hz - we found it necessary
to sample the input data at 60 hz to prevent phase induced instability.
That's 15X the maximum passband frequency.

I see no reason why this kind of effect does not apply at audio frequencies
as well.