What makes a Digital Interconnect

The 75 ohms refers to what is called "characteristic impedance", which has relevance only to frequencies that are much higher than analog audio signals (such as frequency components that are present in digital signals, video signals, and radio signals). It cannot be measured without special purpose test equipment that can deal with those high frequencies.

To a close approximation it is equal to (the square root of (inductance per unit length divided by capacitance per unit length)).

In the specs you've listed, Cp represents capacitance, the p denoting that it appears as a parallel capacitance between the center pin and ground. Ls denotes the inductance, the s indicating that it appears in series, along the length of the wire.

I have no idea why the series inductance for the ground shield appears to be specified as equal to the series inductance for the center conductor. I would expect the inductance across the shield connection to be far less.

Also, 56pf and either 1.6uH or 3.2uH (which would be the total round-trip series inductance if the center conductor and the ground conductor/shield were each 1.6uH) do not come close to equalling a 75 ohm characteristic impedance. 56pf and 1.6uH compute to a characteristic impedance of 169 ohms, while 56pf and 3.2uH compute to 239 ohms.

Re your question about bandwidth, 1GHz is a vastly higher frequency than a cable terminated with rca connectors would ever be used for, and probably just represents the frequency range over which the cable itself (apart from the connectors) can supposedly be used, without unreasonable signal loss. Although the spec is meaningless without cable length and attenuation for that frequency also being specified.

Regards,
-- Al

Al,
Something tells me you have more than a passing fancy with audio gear, lol.

What engineering school did you attend :)

Howard

What engineering school did you attend?

Columbia (BSEE); RPI (MSEE). However, my engineering career (now retired) was in defense electronics, not audio.

Best regards,
-- Al

Actually, despite having at least 3 ICs specifically designed for digital , I use a standard IC for carrying the data between transport and DAC. I find it does a better job in MY SYSTEM. I see some of the Digital cables are specified at 110 Ohms instead of 75 and some makers say the 1.5 M is the proper length. Al , I will leave the technical details up to you, my attitude toward them is the same as Charles Lamb's toward matters concerning Space and Time: "Nothing puzzles me more than such questions and yet nothing bothers me less as I never think about them". Seriously, I have tried a variety of dedicated digital ICs as well as standard ones and never found 2 who were indistinguishable. Possibly if I had tried freebies or really cheap ones this would have happened. Unless you want to do some serious research don't worry too much about the specs., just hook it up and see what it sounds like.