what is the major difference between digital coaxial cable ( for DVD output) and normal RCA cable?

Question

If I connect an ordinary audio/video calbe to DVD coaxial output, does it really cause big loss to signal? What is the frequency range of "digital audio signal"? Is it higer or wider than video signal?

Answer 1

Analog audio cable is better if it has high shielding and low capacitance (to prevent high frequency rolloff).

With Digital Coax it is most important (along with coaxial construction) to maintain a 75 ohm impedence and low signal loss.

While 75 ohm coax works well for both analog and digital audio connections, simple RCA stereo cables when used for a digital coax connection are subject to electrical interference and will allow rounding of the digital squarewave signal over distance due to impedence mismatch ... so while they will work in a pinch, should not be used at more than short distance.

See Blujeancables.com for good info on what makes for a top quality cable for either use.

Answer 2

You can use a Video cable. This is what the people who wrote the SPDIF specification had in mind.

Video cables are all made with "75 ohm coax". This matches the impedence of the coaxial-digital connectors.

AND: Many L/R audio cables are also made with 75 ohm coax, but many of them only use 50 ohm coax and ... un-known RCA plugs.

These cables will actually work. They do not cause "loss of signal" - but the mis-match causes a reflection in the cable that messes up some signals. Your audio will cut out every few minutes or every few seconds if you use the wrong cable.

So try to use a video cable with yellow RCA plugs and you should be fine.

Answer 3

A digital signal requires more bandwidth than an analog signal. Impedance is very important when considering a cable for a digital application. This distance is also very important due to the cliff effect. If you're going 3 to 6 feet then you will be fine with what you have. Anything longer you should use coax RG59 or RG6. Either will do just fine. Most people use RG6 but RG59 will work just as well. I get my cables made from www.cablesnbulbs.com

They custom make them to length, cheap and they look good.