Coaxial Cables

Discussion in 'Beginners, General Questions' started by ScottJChap, Nov 7, 2003.

  1. ScottJChap

    ScottJChap Auditioning

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    I went to the store today to check prices of A/V cables and saw that coax cables are for both Audio and Video

    I don't know much but that sounds to me like having both audio and vieo going through ONE cable would degrade quality

    what's the deal???
     
  2. Brooks

    Brooks Extra

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    I think you misread the signage. A coaxial cable can be used to transmit video data, OR analog sound data OR digital sound data. But only one source, not 2 or three on the same cable. Coax is necessary to use wires for transmitting digital sound from say a DVD player to decoding receiver. Coax is necessary for transmitting some of the higher bandwidth video signals.

    Hope that clears things up.
     
  3. Vince Maskeeper

    Vince Maskeeper Producer

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    This question is complex without knowing what you actually saw...

    But know that coax cable type is simply a cable having two coaxial conductors with the outer conductor serving as an electrical noise shield for the inner one. This type of cable construction can be used to carry video data, analog or digtal audio data, etc etc etc... There is no specific "use" for a coax cable- it is used for all kinds of things.

    The confusion often comes in because "coax" is traditionally used in conjuction with or interchangably with "cable" as in "cable TV". As such- the signal coming from the wall to the cable box is often called the "coax cable"- and many people still associate coax with this use.

    In the case of "cable TV" signal the signal carried is a RF modulated signal- which carries both the video and audio on one cable in a freq modulated carrier. In the case of hooking your VCR up to your TV using one of those single wires with the F-type (screw) connector- the same principle is used: the video and audio signals coming off the VCR are modulated in a RF signal and carried on a single wire.


    In the case of RF video, this is certainly a degrading of the signal overall - and in any case where you can use separate carrier cables, you should...

    However the cable you saw at the store might not have claimed to carry both audio and video simultaneously-- rather might have been claiming to be a generic coax type that was suitable for either audio or video or digital audio use (without offering to carry all 3 at the same time!)

    Hope that helps

    Vince
     
  4. Iver

    Iver Second Unit

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    The terminology is pretty confusing.

    Coaxial cable is used for a number of A/V purposes. These are the main ones:

    1) When it carries the RF broadcast TV from your antenna or a cable signal, then the one cable takes the entire signal which includes both video and audio information.

    2) Video (the line-level video, usually connected with a yellow RCA jack labeled "video"). For short runs (less than one meter) you can also use an audio-type cable as long as it terminates in the appropriate RCA plugs.

    3) Digital audio. One of two common types of cables used to connect the DD, DTS, or PCM from/to a disc player. The other type is a fiber-optic cable ("optical").
     
  5. ScottJChap

    ScottJChap Auditioning

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    Thanks a lot
    what the package said verbatim was

    "For Professional Video and digital sound"

    That is confusing too, but it must (and does) mean wither or, not both with one cable

    that does answer my question though

    Scott
     
  6. John Garcia

    John Garcia Executive Producer

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    Coaxial digital cable and basic video coax with RCA terminations may be used interchangeably.
     
  7. ChrisWiggles

    ChrisWiggles Producer

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    The reason they don't list regular audio, is that digital connections, and video connections should be 75ohm, wheras analog audio can be pretty much anything. That's why any good 75ohm coax cable can be used interchangeably for digital connections, or video connections, but ALSO for regular analog connections. However, the converse is not always the case, analog audio coax wires may or may not be 75ohm, and unless that you can establish that they ARE 75ohm, then it's best not to use them for video or digital connection, although they would probably work *ok*.
     
  8. ChrisLazarko

    ChrisLazarko Supporting Actor

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    I found a typical POS analog audio cable to do the trick when I hooked my computer up to my reciever... although it wasn't the best it did work and do the job, just scratchy and not always defined like it should be in some areas.
     

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