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Thread: XYI format

  1. #1
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    Default XYI format

    Is the blanking I channel in an XYI show basically an inverse of a solid state modulation channel?

    Meaning is it off when color should be there and on when it shouldn't ?


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    Hey Sir J -

    Quote Originally Posted by polishedball View Post
    Is the blanking I channel in an XYI show basically an inverse of a solid state modulation channel?
    The "I" stands for "Intensity", which - in the 'old days', was typically handled by an actual Mech. Galvo (aka, the 'blanker'..) - so you could have nice, smooth analog 'Intensity control', from Full Off (blanked..) to Full On.. So, the V-scale would (usualy) be Higher, than Color-mod channel sigs, say for an AO.. It could, of course, be set up with 'TTL', so it was more a straight 'on/off blanking', but as with Color, analog was of course, preferred..

    ..I assume you're asking relative to your ADAT-rip endeavours in the PMs? (I'm guessing, perhaps, you are seeing 'inverted' signals on those 'I' tracks?) If-so, there Was such a thing as 'blanking reverse', which, IIRC, was to accommodate either a Mech-blanked Galvo Amp, or, an 'early Gen DPSS' that required a 'reversed signal' for Intensity.. I think that was common, for example, in Laser Media 'ZAP'-based systems, where that was typically 'reversed'.. IIRC, 'LFI' did it that way, also..

    ..I'm sure P'fesser Steve / other Elders will correct me where I'm remembering wrong..

    Anyhoo, tty in PM..
    j
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    This is an xyixyilr LFI format. Basically curious if they can be converted to single color playback to start. The pm was straight ADAT Ilda except for track 6.

    Thanks for the info
    Last edited by polishedball; 01-09-2017 at 19:40.
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    Quote Originally Posted by polishedball View Post
    This is an xyixyilr LFI format. ...curious if they can be converted to single color playback to start. ..
    If I am 'seeing correctly' (and, that's getting harder and harder, these days.. may have to succumb to old-man glasses, soon.. an XYI, XYI, L, R (audio, yes?) sounds like yer Classic 2-channel XY w/ Mech blanking, and L/R audio set-up..

    ..May or may-not be for a '3D' set-up, you'd have to see if the XY-data was 'cloned, w/ offsets', or, truly 'complimentary' output (one Channel supplanting the other - so, therefore, the blanking (I) 'timing' (when each channel was using it..) Might be different..) Very common format back in the 'Reign of the 6800s'..

    ..If, however, it was intended as a 'stereo' / Chromadepth / fakey-3D set-up, then both sets of XY data - And the I - would be the Same, for each XYI-set of tracks, except for the 'stereo fakey-3D' offsets, for each XY channel.. In such a case, the Intensity could be used for 'either channel', for what you are - I think - wanting to do..

    Hope this helps, Cheers..
    j
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  5. #5
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    The notes on the older reel to reel FM encoded tapes in XYI-XYI-Laud-Raud that I have, mention a red (KR) and blue (AR) scan head....
    When you look at the content on a o'scope its usually two abstracts overlaid, although one I have has some graphics. I'm sure the operators' console added color chop/sequencing and offsets/sample and hold as needed.
    Well, I'm quite sure as the home-made console I have from the donating institution did do that to the tape input...


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    it looks like audacity has a channel "invert" function. that might fix your color modulation.
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

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    Quote Originally Posted by swamidog View Post
    it looks like audacity has a channel "invert" function. that might fix your color modulation.
    Inverting the channel will also invert the DC offset. So I don't think this will work.

    Years ago I worked on a wave file set that had this kind of blanking and I had to use GoldWAVE. It has an expression evaluator. I don't remember exactly what math I used, But I think I inverted it and then added or subtracted the proper DC offset.

    I'm not sure what you have but it might be compatible with the Z input of an O-scope; which is beam density. It is zero or off when the input voltage is high and full on when the voltage is zero.
    Last edited by james; 01-10-2017 at 13:16.
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    there is some control of dc offset.

    http://manual.audacityteam.org/man/dc_offset.html

    Quote Originally Posted by james View Post
    Inverting the channel will also invert the DC offset. So I don't think this will work.

    Years ago I worked on a wave file set that had this kind of blanking and I had to use GoldWAVE. It has an expression evaluator. I don't remember exactly what math I used, But I think I inverted it and then added or subtracted the proper DC offset.
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  9. #9
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    I do have the FM decoder box..
    What I no longer have access to is the reel to reel machine...
    I have a few of the tapes as multi-track wave on hard drive, if I have time I'll take a look at the I tracks.
    However, when not at work, I'm a caregiver for an 84 year old, and my evenings are often burnt with that...
    Steve
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