HDTV component video switching - required bandwidth ?

Discussion in 'Archived Threads 2001-2004' started by Nancy Parr, Dec 17, 2001.

  1. Nancy Parr

    Nancy Parr Agent

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    I'm looking to buy a DENON AVR-2802 or a Harman/Kardon AVR-320 but one thing is bugging me. I need to have a receiver that will do the job for HDTV component video switching. I eared that HDTV component video switching need a bandwidth of 37 MHz and the DENON only have 27 MHz and the H/K 35 MHz. I don't need to switch 720p but only 1080i, so is it still necessary to have a receiver that can switch 37 MHz ? What bandwidth is really required to switch 1080i HDTV without any resolution loss ?
    A prompt answer would be greatly appreciated, cause I'll probably decide today which one I'll buy.
    Thanks.
    [​IMG]
     
  2. Martin Rendall

    Martin Rendall Screenwriter

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    If I can jump in too, will my Yamaha RX-V1000 be able to switch 1080i and 480p?

    Thanks,

    Martin.
     
  3. Allan Jayne

    Allan Jayne Cinematographer

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    With today's TV sets you can get away with 22-25 MHz for 1080i regarding A/V receiver video bandwidth. The TV set is the limitation, it almost certainly can't make a spot as small as 1/2000'th the screen width which is what the 37 MHz is needed for in doing 1080i. Half the bandwidth means the smallest spot achievable is twice the width. (For 720p, the 37 MHz bandwidth is needed to get its smallest spot size of 1/1300, or rather 1/1280 the screen width.)
    If the same set of component jacks on the TV takes 480p, 1080i, and even 480i with the TV autoselecting (or even manual selecting using the remote), you can run all these inputs into the A/V receiver's component video jacks with the usual one cable set going to the TV.
    Other video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  4. Todd Hochard

    Todd Hochard Cinematographer

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    I have the Denon AVR-3300, which includes the 27Mhz component video switching. For a time, I was running my DVD and HD via the circuit. I have since changed it, but I do not see any difference in picture quality (it was an easier setup with my TV to have them on different inputs). I REALLY looked for it, as I figured I would see it. I couldn't.

    My TV is the Pioneer Elite 510HD. I agree with Allan- with the currently available 7" CRT-based HDTVs, I think you would have a real problem seeing the difference. The actual RESOLVING capability of my set, as currently setup, appears to be 1100x600 or so, based on beam spot size. The aperature grill pitch/shadow mask of currently available direct views is even lower than that.

    If you're not running HD DLP or DILA, I wouldn't worry about it.

    Todd
     
  5. Nancy Parr

    Nancy Parr Agent

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    Thanks Allan Jayne for your interesting post. My TV set is a Toshiba TW65X81. Do you think I'll be OK with the DENON with its 27 MHz bandwidth component video switcher ? According to DENON the answer is "yes" but considering the investment (more than $1200 CDN) I want to be sure that what I'll buy will do the job.
    Thanks Todd Hochard for your post that seems to confirm that the 27 MHz could do the job for 1080i.
    Thanks again.
    [​IMG]
     
  6. Phil

    Phil Stunt Coordinator

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    Martin Rendall,
    I too was concerned with the RX-V1000's ability to switch H.D., so I e-mailed Yamaha and they replied with this:
     
  7. John Morris

    John Morris Guest

    It is true that most sets and HD sources do not use the entire 37Mhz bandwidth... yet, isn't it a good idea to not restrict your video to your switching device? I originally used a Denon 3801 to pass my DVD players component signal. Since then, I found that a higher quality cable provided much improved images and that the Denon slightly degraded that signal. Now, I go directly from my DVd into my HDTV. Recently, Outlaw announced that they were going to upgrade their video switching bandwidth to 37Mhz for their soon to be released 950 Preamp/Processor. For the future, if I am going to switch component inputs, I want a minimum of 35Mhz.
     
  8. Martin Rendall

    Martin Rendall Screenwriter

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    Wow Phil! That's exactly the kind of feedback I was looking for!

    Martin.
     
  9. John Morris

    John Morris Guest

    I've been thinking a bit more on this topic and in the meantime also communicated with a friend who knows more on this topic than I do, and here is what he reminded me of...

    That another spec to consider is the speed of the scanning, which is also expressed in MHz, as opposed to the actual video bandwidth. The two are separate things and not as related. Also, that the bandwidth of the incoming signal is currently limited to 30 MHz by the SMPTE and EIA/CEA standards as referenced in their newsletter, and that when running wires and connections for component video you want to avoid a situation where the combination of long wire runs and "too wide" bandwidth would cause the wires to act as an antenna for undesirable RFI/EMI ingress and interference. Just thought that I'd give you a bit more to think about.
     

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