USB cable comparisons

[marce]

5 hours ago, seeteeyou said:

 

 

Maybe signal integrity ain't snake oil after all?

Signal integrity has been an important part of electronics since Oliver Heaviside, he came up with the telegraphers equations, circa 1880..... So its not that new.

[marce]

7 hours ago, Em2016 said:

 

True but on the other hand, as @marce said:

 

"A problem for domestic audio is external connectors, you never know what sort of cable is going to be hung on the end of the device, so you have to design for a generic cable and hope the punters use somthing similar and not some exotic antenna,?"

 

 

I was referring to the handling of EMC issues within the component, specifically conducted immunity. Cables hanging of kit are a possible source of introducing noise into the circuitry, not only can they act as antenna's picking up rf, but also couple to other sources of noise  such as near by mains cables (usually inductive coupling). This affect not just audio but any system. This can also work the other way, with the cable acting as a noise source (radiated emissions) and thus possibly causing problems to nearby equipment. Now imagine a set up where you have several pieces of kit interconnected by various cable, power cables, not just mains, but often these days via wall warts (often the work of the devil) all close together (such as a domestic audio system) and you could have an EMC nightmare, especially if the cables are not to the required specification (such as unshielded USB).

More on EMC testing to save me blabbing on.

https://emcfastpass.com/emc-testing-beginners-guide/emc-immunity-testing/

 

[marce]

Velocity factor tells you how fast the waves propagate through the wire, a VF of 1 means the signal speed is approx 300mm/ns so

VF=1 a 1m interconnect would have a propagation time of 3.33ns... The difference for the cables listed is from 5ns to 3.9ns, even a two m interconnect is not going to be an issue.