Is digital really digital?

Discussion in 'Beginners, General Questions' started by Paul Slund, Sep 17, 2003.

  1. Paul Slund

    Paul Slund Extra

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    I'm confused about digital signals...I have satellite TV, which Bell ExpressVue claims is 100% digital. However, before I bought my new TV, I didn't have a digital TV. From what I've learned, digital TV is ATSC and regular TV is NTSC...how could I get digital signal on a non-digital TV? And now it appears that the non-digital signal doesn't look good my new TV...

    help...
    Thanks.
     
  2. Lew Crippen

    Lew Crippen Executive Producer

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    The satellite signal is indeed digital—but your satellite receiver does a digital to analog conversion before it passes the signal to your set.

    This is true even if you have a digital TV, assuming that you are using component input to your TV. The only true way to get a digital signal to your TV is via DVI (or Firewire), if both your receiver and TV are DVI capable.

    I assume that your new TV has a pretty large screen. What you are seeing is how bad the NTSC signals really are (especially if they have been compressed by the satellite service).
     
  3. Jack Briggs

    Jack Briggs Executive Producer

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    Meanwhile, we won't tell Paul that most "digital sets" are not really "digital" at all but are in fact analog sets capable of displaying digital signals at the proper scanning frequencies.
     
  4. Paul Slund

    Paul Slund Extra

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    ??? Really? I thought Digital TV was the way the manufacturers are going (Hitachi even calls their TV's digital TV's...although mine is a Toshiba). Does this have something to do with what I've read that there isn't a standard for digital broadcasting yet. If so, is HDTV (ie. 1080i) the only digital standard that most broadcaster are employing?
    Does this also mean that I can't get my satelite signal into my TV in pure digital format (using my S-video cable)?

    Thanks.
     
  5. Jack Briggs

    Jack Briggs Executive Producer

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    CRT-based sets that are ATSC-capable are still "analog," though they scan fast enough (and have enough resolution) to display digital and high-def broadcasts. There are, however, "true" digital TVs: DLP, LCoS, etc.
     
  6. AllanN

    AllanN Supporting Actor

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  7. Lew Crippen

    Lew Crippen Executive Producer

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    Allan, Jack’s point is that the actual CRT display process is analog (as you observe), no matter how much of the earlier electronics are digital (including the input signal), in the end, that cathode ray tube moves the scan beams via magnetic plates deflecting the path of the beam, using good, old fashioned analog signals to vary the voltages on the plates—and even if this were changed to be digital, the beam movement itself is analog, not digital.

    This as opposed to Jack’s examples of digital displays—a plasma screen for example works digitally.

    I was going to precede this by saying that I can’t speak for Jack. I just realized I had. [​IMG] Oh well.
     
  8. Jack Briggs

    Jack Briggs Executive Producer

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    Well, as usual, Lew got it right and so there ain't a problem with him "speaking for me." [​IMG]
     
  9. Allan Jayne

    Allan Jayne Cinematographer

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    It might be noted that, for a CRT based HDTV receiving hi-def signals from an external set top tuner box via component video cable, the digital TV shows are probably better off being handled strictly with analog electronics all the way from the input jacks to the CRT's while analog broadcasts are better off handled with digital electronics for the comb filter and a de-interlacer.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  10. Paul Slund

    Paul Slund Extra

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    Okay...so even if my TV says it's NTSC standard, it is high-def and therefore ATSC-capable. The fact that I have digital satelite doesn't matter because it gets converted to analog, and the fact that I have a much bigger screen (gone from 27 4:3 to 57 16:9) just demonstrates how crappy the signal was in the first place? Does that sound about right? If so, how do I go about getting a good picture (ie. the non high-def picture?)out of satelite? Or am I stuck?
     
  11. Jack Briggs

    Jack Briggs Executive Producer

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    Your TV has higher resolution that what you've had before, and now you're seeing flaws in the NTSC programming you couldn't see otherwise. Bad signal source, bad picture.
     

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