I've seen this and similar diagrams used over and over again by a lot of people who should now better. This kind of diagram can be interpreted two ways
(a) the diagram maker has no idea how sampling works
(b) the diagram maker made it to illustrate a pathological case to make quantization noise obvious, that is, the diagram shows fs=infty with a four level / two bit ADC with no dithering
In any case, it has nothing to do with how digitizing audio works.
> It is true that the amplitude dimension (only) is quantized to (typically, 16 or 24) bits, which you could detect with a very good oscilloscope.
Nope, normal scopes work with 8 bits ADCs and manage 10 to 12 bits in ERES and similar modes (... they don't really get to 10 or 12 bit SFDR though ...). Some special scopes have 16 bit ADCs, but you'd still be hard pressed to detect the difference.
Also, while again a "counterintuitive result" in a certain sense, the dynamic range of a 16 bit audio signal is greater than 96 dB, that is you can encode and actually discern noises below -96 dbFS. This is because the 96 dB figure assumes a white dithering signal, which is not used.
Of course, all that doesn't really matter with pop music. Who needs >100 dB SNR and DNR if the piece you are encoding only has 10 dB DNR anyway?!
I've seen this and similar diagrams used over and over again by a lot of people who should now better. This kind of diagram can be interpreted two ways
(a) the diagram maker has no idea how sampling works (b) the diagram maker made it to illustrate a pathological case to make quantization noise obvious, that is, the diagram shows fs=infty with a four level / two bit ADC with no dithering
In any case, it has nothing to do with how digitizing audio works.
> It is true that the amplitude dimension (only) is quantized to (typically, 16 or 24) bits, which you could detect with a very good oscilloscope.
Nope, normal scopes work with 8 bits ADCs and manage 10 to 12 bits in ERES and similar modes (... they don't really get to 10 or 12 bit SFDR though ...). Some special scopes have 16 bit ADCs, but you'd still be hard pressed to detect the difference.
Also, while again a "counterintuitive result" in a certain sense, the dynamic range of a 16 bit audio signal is greater than 96 dB, that is you can encode and actually discern noises below -96 dbFS. This is because the 96 dB figure assumes a white dithering signal, which is not used.
Of course, all that doesn't really matter with pop music. Who needs >100 dB SNR and DNR if the piece you are encoding only has 10 dB DNR anyway?!