The Logic Off Topic list

Dennis Gunn <dennisg@...> wrote:

>Once about 9 years ago on the DAW I remember writing about how the
>digital wave form for a sine wave up around say 19.k looks like a
>broken spiral staircase and how I find it hard to believe that any
>amount of filtering is going to turn that into a clean sine wave.

Nine years is a long time in the history of DAWs...

It is entirely feasible to digitally filter a square wave to produce a
sinewave within the practical limits of a digital systems parameters,
which is effectively what is going on in what you describe above.
In any case, why is it hard to believe? Isn't filtering one of
the cornerstones of sound processing? Was Fourier wrong??

The problem lies in allowing >> nyquist frequencies to get to the
the output, as for example would happen in an unfiltered saw or
square oscillator at even modest frequencies with a less than ideal
filter at the converter stage. Better filter implementaions,
Greater sample rates and higher bit depths allwork to minimise this
problem...

>A
>lot of peaple called me ignorant for being decieved by the look of
>data but Nothing I have seen or heard since has ever convinced me I
>was wrong.

Though I don't entirely disagree with you, from what I have learned of
you on this list I don't find that statement a complete surprise.

S.