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Old 11 October 2016, 12:59   #21
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Join Date: Jun 2010
Location: PL
Posts: 1,546
Originally Posted by meynaf View Post
I real life you get a little more than 14 bits, in fact. You should really have a look at how the calibration works.

I will be glad to read description (technical) but i think you are not electronics engineer when you said that 8 bit DAC may have over 14 bit accuracy (it can be done but then it must be 8 bit DAC made internally with over 14 bit accuracy which is usually not the case for technology in mid of 80's previous century).

Check popular DAC in those time (70's design i believe used in Paula prototyping stage) DAC08 - depends on version (grade) linearity was between +-0.1 to +-0.39%, +-0.1 means approx 0.2% linearity i.e. around 9 bit linearity - this is for best case scenario, now imagine 4 DAC like this in cheap non analogue process (as we know CBM/CSG was specialized in digital IC not analogue one) - well i would say it is highly doubtful that CBM/CSG will do expensive laser trimming for every 4 Paula DAC and in real life scenario Paula DAC linearity is more close to+-.39% or even more non-linearity and it is not possible to stack two 8 bit nonlinear DAC and expect higher linearity (unless nonlinearities in both DAC will compensate but this imply differential topology and lot of hassle at the output stage)
Gain from so called 14 bit is that every added bit reduce quantization noise by 6.0206dB and 10 - 12 dB is easily perceivable (for most of people 11 - 12 bit will sound unperceivable same as 16 bit, add to this power supply noise where in Amiga overall power plane analogue design is far from CD standard).

Last edited by pandy71; 11 October 2016 at 14:01.
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