Arny Krueger wrote:
"Chris Hornbeck" wrote in message


On Tue, 16 Nov 2004 22:09:24 -0500, "Arny Krueger"
wrote:


It may be advantageous
to dither that; ie, sometimes shift in a 1 instead.

Exactly. The problem is that the binary represenation of an analog
voltage is rarely exact. There is almost always quantization error.
When you double the data by means of simple shifting, you also
double the quantization error.

OK, but how about in a theoretical, ideal case that's properly
dithered and has no quantization error. Does a shift cause any
quantization error?


The shift does not add or subtract quantization error. Instead, it
multiplies the error that is already there. As was pointed out, the SNR does
not change, but the noise level increases.

Given that the final playback level will presumably be unchanged, the
only practical effect of the shift is that subsequent processing MAY be
more precise due to the newly available low-order bits. Whether that
actually happens depends on the algorithms used.