VGA Switch Box for High Def signals?

Discussion in 'Archived Threads 2001-2004' started by Tony F, Jan 18, 2002.

  1. Tony F

    Tony F Auditioning

    Joined:
    May 24, 2001
    Messages:
    8
    Likes Received:
    0
    Is there a recommended product for switching SVGA (DB-15) signals for 1080i HDTV and computer monitor (1024x768 and above) projection?
     
  2. Phil A

    Phil A Producer

    Joined:
    Oct 1, 2000
    Messages:
    3,171
    Likes Received:
    38
    Location:
    Central FL
    Real Name:
    Phil
  3. Tony F

    Tony F Auditioning

    Joined:
    May 24, 2001
    Messages:
    8
    Likes Received:
    0
    Thanks much Phil!

    Audio authority looks like they have a solution for me!

    What do you know about bandwidth ratings vs resolution of display device. Should the rated bandwidth of a signal path product meet or exceed the full screen resolution times refresh rate (i.e., for 720p, resolution > 720 lines X horizontal resolution X 60 refreshes/sec)?

    Tony F
     
  4. Allan Jayne

    Allan Jayne Cinematographer

    Joined:
    Nov 1, 1998
    Messages:
    2,404
    Likes Received:
    0
    Bandwidth as defined is the frequency range over which the worst reproduced or passed frequency comes out with at least half the strength of the best (-3dB). If two products barely met their advertised bandwidth, a signal path going through both of them will not meet that bandwidth spec. (You know what one half of one half is.)
    Therefore to get so much bandwidth for the entire path, the various components including cables each need more than that bandwidth, precisely how much more is difficult to guess without use of test equipment.
    For HDTV you need 37 MHz video bandwidth. But the typical HDTV set can't make a spot smaller than 1/1000'the screen width, which is two 1080i pixels wide. (It can still center the spot on any one of the 1920 x 1080 possible positions compared with 720 x 480 possible positions for 480p.) So if the signal path with switch box has just half the needed bandwidth you won't see the difference.
    More:
    http://members.aol.com/ajaynejr/bandwid.htm
     

Share This Page