jeremya
Member of the Trade: Hi-Fi Foundations
- Joined
- Jun 12, 2014
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No worries - we are dealing with a complex situation....
Thank you so much for the detailed tutorial, Rob! Definitely learned a lot there, although I'm still trying to fit the mental model together.
Here's my layman's takeaways from what you wrote... feel free to correct them!
- Despite what Andreas Koch implied, not all PCM (perhaps even not much PCM?) is converted from a 1-bit DSD stream, because n-bit delta-sigma ADCs are more commonly used when PCM is the target.
- "Pure DSD" recordings (which are optimized for that 1-bit stream) still have timing errors due to how long it takes the modulator and the noise shaper to "notice" a rise or a fall in the input voltage (significant enough to warrant the output bit being flipped).
- Errors in DSD are a function of sampling rate (and some other factors), so higher sampling rates (like quad-DSD) are less error-prone, but the fundamental issue with a 1-bit modulation remains.
- multi-bit PCM sourced from an n-bit delta-sigma ADC process has both the headroom to deal with a wider range of input values and the ability to be dithered effectively, which a 1-bit DSD signal lacks. This affords your process the ability to reconstruct the original analog input with much greater fidelity from PCM than from DSD, as there are fewer timing errors 'baked in' to the bits.
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