Jeremiah Moore wrote:
> DSD (Direct Stream Digital) was developed by Sony as an archival
> format. It's since become part of the DVD standard, where it is
> called "Super Audio CD" (SACD), though I think only high-end players
> support it. It uses extremely high sample rate (2.822MHz) 1-bit
> sampling (that's 44.1KHz x 64). For those not familiar with 1-bit:
> all that is recorded per sample is whether the analog input is going
> up or down relative to the previous sample. The net effect is to
> eliminate the source of a lot of problems with conventional PCM
> digital recording. In fact, 1-bit converters are pretty normal fare
> in PCM recorders - the 1 bit signal is simply decimated and
> interpolated to 16 (or 24 or whatever) bits at the requisite sample
> frequency.
I'm wondering about the description as specifying only if the input is
going up or down using 1 bit.
Does this mean a steady state cannot be recorded. Or records as a jaggy
up/down thing? Thus introducing noise at the sample rate?
It would seem the minimum choices are up, down, or no change. a bit
still says yes or no to one question only, and the three choices will
take two questions to specify.
And you would certainly be limited to really high frequencies for a
sample rate to get any sort of resolution. To get from one end of the
scale to the other would take at least the number of samples equal to
your increment value per sample. And that assumes the curve you are
describing does not vary. You can only describe a very limited slope
choice for the sine wave as described here. Or else you must use
multiple samples to describe the slope at just one point.
Walt
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