Noise – Part 4
To summarize and simplify, something like the following happens. A PCM data stream is fed to the DAC input through the I2S connector, oversampling is added, dithering, and then the stream is sent to a noise shaping decoder. At the end, a one-bit stream is formed, it passes through an analog low-pass filter, where the final audio signal that we hear is already obtained.
A multi-bit DAC is more complex: in addition to the above, it also uses DEM technology.
WWW
If you want to understand the details, please read the materials in the links, there is information not only about sigma-delta-DAC, but also about sigma-delta-ADC.
Article on delta-sigma modulation on microsin.net
Notes from E. I. Vologdin’s lecture on sigma-delta modulation
Modern digital-to-analog converters are complex devices. But the use of these technologies is necessary to artificially expand the dynamic range, and they are generally used to overcome the limitations of CDDA and MP3 formats. If the recordings were originally published in high resolution PCM (192 × 24), or better in DSD format, then there would not be as many technologies and complex digital transformations. In the case of DSD, interference with the quantized signal is not necessary at all, at least during playback.
Conclution
The development of recording and playback in the digital age has been challenging and arduous. With the invention of the compact disc, analog audio practically ceased to exist in just a couple of decades. Good or bad: everyone decides for themselves, but I would like the possibility to choose to remain. If it is not between digital and analog, at least how and with what quality to listen to your favorite music. Unfortunately, now there is hardly any other option. Few people are releasing high definition music these days, aside from crawler enthusiasts. The only fault for this is the recording studios, who decided to limit themselves to a single format: CDDA.
All that’s left is to sympathize with the musicians! How much effort and time they put into creating music, but their work isn’t even preserved in decent quality. The solution would be to record on the master tape or at least on DSD. But the recording studios will not waste extra effort, because they are satisfied with the current situation (PDM).
