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Thread: CYGN-B

  1. #61
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    I'm pretty sure what's pictured is a sin/cosine pot, and yes they're continuous rotation. Most potentiometers have stops, but it's not a requirement. Perhaps the stepped effect was the result of the rotation circuit's design. I've thought about introducing a sample and hold on a joystick signal for a similar effect...
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  2. #62
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    You're right. I just learned there is such thing. It's this:

    https://www.ebay.ph/itm/Potentiomete...0/293190383319
    Attached Thumbnails Attached Thumbnails Dejur_HP300.jpg  


  3. #63
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    sinusoidal modulation signals
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  4. #64
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    I archived this a few years ago (written by Brian?):

    Most of the circuit boards in Laser Images' equipment had 4 letter acronyms. The Digital Offset Generator board's was shortened to three. Calling it the DOG card may have simply followed in the great tradition of D-PIG card. It could do several images per scanner as well as static and dynamic offsets. The popcorn effect produced by earlier equipment suffered in existing shows due to the connection of offset gain to the DOG card's multiplying DACs. The DOG card was limited by it's small memory 2k? of RAM, 2k? of ROM. This was a function of board space since in addition to memory a 6502 cpu, glue chips, and 8 D/A converters had to fit on a "standard" Vector wirewrap board. (That's about 4 x 5 inches of board space.)

  5. #65
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    About that ROM...

  6. #66
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    I should have mentioned that since the amplitude modulation was done by varing the supply voltage to the 74c chips the amplitude modulation voltage couldn't go below +3 volts. You've got a +/- thing going on there. It's nice, but it'll keep you from doing the old images when the AM is all the way up.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  7. #67
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    Ahhh... I wondered about that.

  8. #68
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    Pay attention to Ron's list of things an offset generator should do, all ye console builders:

    This card also allowed shapes to "pong" around and "fly" around (can't think of a term for this motion - kinda swooping slow lissajous motion). and fly from the center to a random point outside. It also generated some beautiful digital shapes

  9. #69
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    There were a bunch of ROMs (actually UV-EPROMS) - pretty much a set for each major show early on.) At some point as higher density EPROM became available some of the boards were modified for at least 8 shows selected with a small rotary switch - if memory serves.
    "There are painters who transform the sun into a yellow spot, but there are others who, with the help of their art and their intelligence, transform a yellow spot into the sun." Pablo Picasso

  10. #70
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    I think maybe the "fly" motion appeared in the number "Duchess".

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