VetNik
AVClub Addicted Member
- 1 February 2008
- 1,498
1. για αποφυγή λανθασμένων συμπερασμάτων (και όποιον ενδιαφέρει),
άλλο είναι το asychronous rate conversion σε ένα dac
και άλλο είναι η μεταφορά δεδομένων με USB asychronous mode όπου εάν ισχύει ιδανικά έχουμε: " When connecting a computer source *** DAC operates in "asynchronous" USB mode (NOT to be confused with asynchronous rate conversion), where the *** DAC synchronises the audio by providing a feedback pipe to the computer. The computer is then effectively locked to the audio device, which has a much more accurate clock and much lower jitter."
2. Και περί Ι2S:
"I2S Vs. SPDIF
I2S is the data format produced by CD mechanisms, it consists of 3 wires: a Frame (or Word Clock), a Bit Clock and a data line carrying a stereo pair of data streams. I2S is intended for connections between chips a few centimeters apart, not between separate boxes. The 3 cables MUST be exactly the same length, otherwise the data clocked into the DAC may be corrupted due to cable delays.
I2S is used in this way to avoid the need for a Phase-Locked-Loop (PLL) in the DAC, in the belief that this will reduce the level of jitter. In reality, the clock from the CD mechanism is typically very jittery, but there is no PLL in the system to filter out this jitter!
SPDIF is well established and gives excellent results in a well-designed system."
για το 1 σωστα τα λες.
για το 2 μπερδευτηκες λιγακι. δεν ειναι I2S απο cd σε dac, οπως πχ η spdif που συγκρινει, αλλα εσωτερικη μεταφορα του σηματος που δεν εμπιπτει στην παραπανω θεωρια...