[sdiy] Digital audio demo on Youtube

[cs80 at therogoffs.com]

I’ve read about the affects of ZOH using standard sample/hold DAC outputs but what’s the alternative?  In mathematical theory, the DAC output should be zero-width pulses whose area equal the sample value.  Do you have pointers to articles / part specs on DACs that try and approach this?

There’s also DSD, but that’s a whole other can of worms and I assume that isn’t what you were talking about.

 David

On Feb 18, 2014, at 11:16 AM, rburnett at richieburnett.co.uk wrote:

> Monty's statement and Achim's reply are true.  The stair-steps are an artifact of the DAC designer's choice to use zero-order hold in their DAC.  The stair steps are not part of the digital sampled signal, they are the result of a design decision, just like the alternative options of linear interpolation, sinc interpolation, etc...
> 
> Zero-order hold distorts the wave shape, does very little to remove the high-frequency sampling images from the output, and also causes significant attenuation of the treble frequencies in the audio.  That's why consumer and professional audio DACs no longer use ZOH today.
> 
> -Richie,
> 
> 
> 
> On 2014-02-18 17:18, MTG wrote:
>> I don't think this guy does any favours at 8:00 when he says that
>> Wikipedia is confusing, "the stair-steps aren't really there". All the
>> (non-1-bit) dacs I see in these old synths generate pretty visible
>> stair steps... plus I'm sure there are lots of "control" dacs on the
>> planet so we shouldn't just assume every DAC is on a PC motherboard
>> (for instance).
> 
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