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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
    fastest
    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.

    http://www.hittite.com/content/documents/data_sheet/hmc841lc4b.pdf




    auch interessant:
    http://www.furaxa.com/PulserSamplerCore.htm



    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.

    Gerhard
     
  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)

    <
    http://www.google.de/url?sa=t&rct=j...=KO_mO3OuJETmIxdZAofhSQ&bvm=bv.42080656,d.Yms
    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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