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Thread: +/- input signal to seperate + and - signals

  1. #1
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    Default +/- input signal to seperate + and - signals

    Hello everyone - I'm still tinkering when I can. Just purchases some new scanners just to check them out and see how they perform. They require separate + and - signal inputs. My output is currently a +/- sinewave. Does someone have a circuit that concerts a sinwave to + and - signals? The input spec for the scanners is 0 to 5V. Please correct if I'm off track with this. I attached photos of the scanners, amp and a drawing of what was in my head.

    Thank you
    Kevin
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  2. #2
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    All you need is a mirror image of your signal. You don't need to separate the phases as in your drawing, just have an inverted mirror of your drive signal for the negative input

    see the example "Ilda Differential Driver" using op-amps in the 2nd document marked ILDA Connector at this embedded link to the ILDA standards


    In most cases you can get started with a pair of opamps per axis, one a buffer, the other a gain of -1 inverting amplifier. You only need about a volt of signal to start with, most amps do not need the full signal of +/- 10V differential.

    You can also ground the - input on the scanner amps and drive the + input single ended. This does not have the noise rejection afforded by the differential signaling.

    You can leave the amp's analog signal input ground pin floating in many cases, if you build the differential driver circuit shown. It can drive well over 100 feet of shielded cable.

    ILDA STANDARDS


    Schematic attached.
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    Last edited by mixedgas; 08-01-2025 at 11:49.
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  3. #3
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    FYI, if you pick up 60 HZ hum using differential signaling, follow the wiring instructions here in this document from Pangolin.

    ControlCenter2

    Steve
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    Perfect. Thank you Steve - you saved the day again.

  5. #5
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    Smile

    Scanners worked perfectly

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