Quantcast

Results 1 to 2 of 2

Thread: How do "Pal Boosters" work?

  1. #1
    Wildside Expert
    Join Date
    Jun 2014
    Location
    Portugal
    Posts
    135
    Rep Power
    9

    Default How do "Pal Boosters" work?

    Right, so I have this old 8-bit machine that outputs ntsc video signal through s-video socket.

    Most of my CRT monitors are PAL so I get picture, but in Black and White.

    I was wondering if any of these 'pal booster' devices I see for sale (saturn/psx/DC) could be hacked.

    But how do these work?

    Is there some kind of frame/rate conversion involved? I thought these would somehow only change the color carrier frequency of chroma from ntsc to pal so that the tv or monitor shows a color picture but leave luma pretty much untouched (@60Hz), so that the end signal is PAL60?

    Let's take this one for example:

    https://www.ebay.com/itm/Sega-Dreamc....c100290.m3507


    I can make out that in the plug that the pins used for video are cvbs, Y and C.
    But from there on what happens?
    Output is RF or CVBS, so surely there is a RF modulator and some IC for mixing Y and C?
    I wonder if it is possible to hack that IC, get Y through RF modulator (disabled) and C through previously used CVBS socket?

    On the other hand, how would the adapter perform if only C was the only signal fed into?
    Would the CVBS socket output C signal at pal color carrier frequency?

  2. #2
    Hedgehog-in-Training Hedgehog-in-TrainingNameless One pyroesp's Avatar
    Join Date
    Aug 2018
    Location
    Belgium
    Posts
    73
    Rep Power
    2

    Default

    I can't find a picture of the pcb of one of those things to see what chip(s) they use, so it's difficult to say.

    Output is RF or CVBS, so surely there is a RF modulator and some IC for mixing Y and C?
    Probably yes.

    I wonder if it is possible to hack that IC, get Y through RF modulator (disabled) and C through previously used CVBS socket?
    Why try to hack the thing when you can just bypass everything and attach incoming Y and C to the RF and composite RCA jack ?

    On the other hand, how would the adapter perform if only C was the only signal fed into?
    You need luma too for generating a correct picture, so I'm guessing it's not going to work.

    Would the CVBS socket output C signal at pal color carrier frequency?
    My guess is yes. NTSC or PAL don't have a different "encoding" for Chroma from what I could find, only the subcarrier is different: 4.43MHz for PAL, 3.58MHz for NTSC.
    They both use QAM to modulate chroma on top of luma.

    The colorburst is also different on NTSC and PAL.
    I wonder what happens if you put the PAL colorburst signal on NTSC...?
    Last edited by pyroesp; 10-15-2018 at 09:14 PM.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •