Spdif coaxial, toslink or aes/ebu ?

[bentoronto]

But isn't the threshold for satisfactory (that is, error-free) digital transmission safety into the non-distorted voltage? If so, all the squiggles at the peak just don't matter.

B.

 

[marce]

Yes and no. These were worst case sims. on a proper layout there would still be ringing but not as extreme due to layout losses. As long as the rising and falling edges are monotonic and any ripple does not go to low to false trigger the data will get through intact. What is of concern is these ripples are excess energy that is not being sunk by the receiver and can cause the silicon to heat up more and extra overall noise. A 75R resistor to 0V solves this and is such a simple addition and improvement to signal integrity far better than trying to build esoteric cables. Don't forget the wavelength of the SPDIF signal is far greater than the average domestic transmission length, so these minor mismatches are not as critical, though the often rather fast rise and fall times of some drivers don,t help the situation.

 

[Speedskater]

SP/DIF is a robust system. For a 44.1 or 48 interconnect, the small difference between a 50 Ohm and a 75 Ohm coax won't matter until the coax length exceeds about 12 to 15 meters.

 

[TNT]

Depends on what you mean by better. S/PDIF-TOSLINK is optical so better for isolation, sounded ok to me but maybe a bit sterile, just not sure jitter was responsible. Actually i cant see how TOSLINK could introduce jitter . Coaxial is great for long runs, sounded fine too but one time i had PC noise issues, optical got around it until i fixed the actual problem. Then i went back to coaxial. AES is the pro version of S/PDIF, not sure if any difference sound wise but it can carry more info (2 channels). You into studio work?

If you derive a clock from the s/pdif, the rise time will govern the jitter. Toslink has much lower bw than a coaxial connection. Very seldom, data is lost on any of them. If you have a buffer on the receive end, Toslink will be superior as there is no way for any electrical interference by galvanic ground, capacitance or inductance coupled, to enter with the s/pdif connection. A slow(er) line always have more jitter than a fast one.

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[marce]

A rise and fall time that is always commensurate with the circuit is best, does SDDIF need sub nanosecond rise and fall times?
I am trying to find a paper showing ow faster rise and fall times effect jitter, but we are talking fast circuits, not low mHz, and are we sure an interface from a few years ago can handle today's fast switching?