Originally Posted by Drake22
About jitter. So are you implying that if I send a same digital sinewave, one through spdif, and one through coaxial, I will get different analog output? No I won't. It will be same analog output, hence the sound will also be the same. It's gotta be an insane jitter to corrupt the signal. Perhaps usb 1.0 or 1.1 dac could cause it but that is obsolete anyway. If you receive different analog outputs from coax and spdif that would just mean that the DAC is defective.
Again noise. No effect on the sound you confirmed that, thank you. Performance? Your sata bus of your harddrive gets the same noise. What kind of noise it has to be to corrupt the data?
- Coaxial is a particular methode of transmitting spdif, so is optical. What do you want to say exactly ?
- It is mathematically proven that jitter, as small as it is, will corrupt the analog signal. Did you even read the first paper I linked ? Jitter as low as 150ps can be reliably measured in practice by analysing the analog output of a DAC. The question is how much jitter (and of which type, signal correlated or not) is needed to have an audible effect. To get an accurate analog signal, you need the correct samples values at the DAC input AND those values must be fed at the correct timing.
- You realize that most USB DAC on the market are still using USB 1.1 receivers from TI, don't you ?
- Don't put words in my mouth. Noise will not corrupt data but it will surimpose itself on the output signal and corrupt the analog signal. Example: depending on which PC I connect my usb DAC to (desktop, laptop on batteries, etc), I can get the noise floor (at the analog output) varying by as much as 6dB. With sensitive headphones, that can get pretty audible.
- SATA has error correction and works only with purely digital devices. It doesn't care much about noise. However, you have to realize that USB receivers, SPDIF receivers and DAC are real time, mixed-signal devices. They are nothing like SATA. You put noise on the spdif receiver supply and the (analog) PLL performance is reduced which in turn reduce the accuracy of the system clock it's producing. You put noise on the DAC supply pins and you'll find part of it on the analog output. It's not a matter of corrupted data.
You could read those too: