Andrew Hobgood wrote:
> > I just suddenly remembered something about digital sound data - the MSB is a sign
> > bit. If you imagine a sine wave being fed into a system that chopped the MSB, i
> > would turn into an 'm' shape..... and it still wouldn't clip.
>
> Are you sure? That format of the data depends entirely on the platform
> on which you're doing the data transfer... most computers (in PC PCM format)
> use signed word (16 bit) storage... though, some use unsigned word...
>
> *pondering*
Minidisc uses 16bit signed audio data as input. Well that's what comes out of the
S/PDIF anyway so I assume it must be part of the standard.
> ahck. my head is broken. I can't figure out whether or not that'd make a
> difference. =P
>
> Although... if it is using signed word, and the sign bit gets dropped, if its
> using two's complement, it'll screw up the two's-complement conversion, and
> possibly throw off the data stream.
Just tried it using assembler.... the wave you end up with is really wierd looking. The
sine wave starts off ok until the point where it goes negative - it then appears as a U
shape at the top of the graph. You and up with something a bit like this (cue the poor
ASCII art)....
__ nununununu __ where the underline represents 0....
Sounds very strange too almost like a pulsing square wave.. very harsh...- it it was
"clipping" this way you would really notice it.
If the data was unsigned, you get a really odd wave that looks like this....
//\\//\\//\\//\\//\\
Sounds like everything is in a wierd echo tube.... strange.... might try and make a
circuit to do this for the electric guitar, it's phreaky but cool....
--
Magic
Location : Portsmouth, England, UK
Homepage : http://www.mattnet.freeserve.co.uk
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"Creativity is more a birthright than an acquisition, and the power of sound is wisdom
and understanding applied to the power of vibration."
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