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fast edges

Discussion in 'Electronic Design' started by Gerhard Hoffmann, Feb 9, 2013.

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  1. from usenet:

    discrete circuits. Do any of the most recent fpga's meet your needs?
    They are in 28nm which is blazingly fast but I'm not sure if the i/o
    would keep up
    I'm after the fastest possible pulses to drive an electro-optic
    modulator, with
    a goal of making light pulses in the 10-100 ps range.

    We are using the SERDES blocks of an Altera part to make fast LVDS
    edges, but
    the edges are quantized to the SERDES PLL clock, currently 1 GHz. The
    stuff that I've seen coming out of an FPGA is around 60 ps rise/fall,
    low level
    LVDS. Delay temperature coefficients are terrible in FPGAs, so even if
    you can
    make fast edges, they drift all over the place.

    This is interesting, if expensive.

    auch interessant:

    schönes Wochenende, Gerhard
  2. Am 09.02.2013 21:51, schrieb John Larkin:Ooohps, this one went wrong...

    was meant as a email pointer to a colleague until we meet on Monday :)
    Thunderbird is !x%$'!!! aargh!

    BTW I'll play this weekend with your ramp generator (the one with the
    AD8009 bootstrap). I have a new Altium Designer installation and
    choose it as an exercise.

    Altium - Camtastic - pdf - offset film from nearby print shop -
    empty board (self etched & drilled) in a long afternoon.

    regards, Gerhard
  3. Am 09.02.2013 21:51, schrieb John Larkin:
    And the rise/fall time to the decision point would be 6 ps of this.
    That means, the "intent" to produce a different output level must travel
    in 4 ps.

    Looks weird. But interesting, nevertheless.

  4. Resublimated thiotimoline semiconductors?

    Best regards,
    Spehro Pefhany
  5. Am 10.02.2013 02:08, schrieb John Larkin:
    or a missing 0 in the tpd spec.
    8 risetimes through a master-slave FF seems ok.
  6. Am 10.02.2013 01:34, schrieb John Larkin:
    Why is the button for "create new" (verfassen in my German version) on
    the top left and "answer newsgroup", forward, Archive on the right side
    under the list of articles... I want my Agent back. But I won't return
    to Windows for it.
    This one is just to fathom how far I can go; I did something similar
    with a switched current source in a time stretcher. We talked about that
    last year.
    It was for measuring the time of flight of just a few photons
    (interpolation between clock edges)

    page 33

    This time I'd like to avoid the dual slope conversion and go
    directly ramp to digital with a LTC2165. Avoids at least the
    second switching, no droop in the slow part of the cycle,
    no comparator bias current etc. And instead of a few hundred
    stretch cycles per second I can get 20Meg at least.

    I use Ammoniumpersulfat and presensitized 0.5mm FR4 made by Bungard.
    6 mil traces and gaps are easy with offset film.
    Strictly single sided plus GND layer, stamp-sized and dense.

    With the Altium snippet feature I can recycle the circuit diagram and
    the layout as a macro for the real design.
    I now have quite a lot of pre-characterized stamps that I can use to
    click a board together (regulators, VCXOs, filters, frequency
    multipliers, phase comparators...)

    regards, Gerhard
  7. Nico Coesel

    Nico Coesel Guest

    Maybe they specced the unpackaged die.
  8. Joerg

    Joerg Guest

    Hint: In Thinderbird you can customize the buttons. Just right-click the
    tool bar where you aren't happy with stuff.

    For example, I added a "Next" button because I find that rather useful
    in newsgroups.

  9. Jasen Betts

    Jasen Betts Guest

    hve you installed "xchm" or is help broken in lyspice+wine too?
  10. josephkk

    josephkk Guest

    I have tried installing xchm and both are still broken. It is very
    possible i did something wrong though.

  11. Jasen Betts

    Jasen Betts Guest

    from your descriptions it sounds kind of messed up.

    you could try a fresh install by temporarily moving your ~/.wine
    directory and reinstalling ltspice, if help and works in the new
    install it's probablly something messed up in your wine install.

    also test www with help -> about -> linear-tech-website
  12. Fred Abse

    Fred Abse Guest

    I used chm2pdf to convert the LTspice help into a nice indexed PDF.

    Better, in fact than LT's own PDF offering.

    Xchm doesn't always work with some later editions, beyond the first page.
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