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2.7ghz spectrum analyzer

Discussion in 'Electronic Design' started by payam, Sep 29, 2003.

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  1. payam

    payam Guest

    hi, natinal instruments has rf signal generator PXI-5660 that can work to
    2.7ghz , can i make something near it as a electronics enginearing student?
    any help would be most appriciated!
  2. Ben Pope

    Ben Pope Guest

    How much do you think has changed in the last 2 days?

    The answer is was no 2 days ago, it's not today, it will be no tomorrow.

    You are extremely unlikely to have the resources available to you, even if
    you had the slightest chance of designing such a thing yourself.

  3. SioL

    SioL Guest

    It can be done, depending on exact requirements.

    A 2-4GHz wideband VCO was published a few years ago by one of our local geniuses,
    Matjaz Vidmar, as part of his excellent homebrew spectrum analyzer.

    If you follow his instructions word by word, you've got a nice VCO. And if you
    add a PLL and attenuators to that, its close to being a signal generator.

    It all depends on what exactly he really needs. And he may be able to get
    testing equipment at university to verify operation.

  4. Ben Pope

    Ben Pope Guest

    Even by somebody who doesn't seem to know whether he's making a spectrum
    analyser or a sig gen?

    Adding a PLL and other bits and pieces to work at the Gigahertz range is
    till not trivial... I'd be very suprised if this guy could make it work.
    OK... just to make him happy...

    Yes payam, it's possible. I wish you luck. :)

  5. Fred Bloggs

    Fred Bloggs Guest

    He's posting from Iran- let Bill Sloman help him out-)
  6. Ben Pope

    Ben Pope Guest

    I thought Bill was from Netherlands...

  7. SioL

    SioL Guest

    What is payam? Anyway, if you're too incompetent to build one, it doesn't necessarily
    mean others can't. (Its a rather long intro)

    The PCB's and parts are readily available, a HAM with some technical
    skills is able to construct this.

  8. Ben Pope

    Ben Pope Guest

    More like who... he's the OP. I'm not talking about me and my
    competencies... I know what they are.

    Try reading the whole thread before commenting - it gives context. And the
    other threads asking the same question from the same OP merely two days ago.

  9. SioL

    SioL Guest

    You guys should really be ashamed of yourself. Even if I was from Iran,
    what's that got to do with anything. I was merely expressing my opinion.

    Go play with the other Ku klux klan members.

  10. I think the title is wrong : the first post was regarding an RF spectrum
    analyzer, this one seems about an RF generator (but the title is
    unchanged...). My opinion is that building an RF generator going up to a
    couple of GHz is easy (just buy a VCO module and apply a voltage on the
    input, you will get something like an RF signal at the output ...), however
    building a reasonnably good RF generator is not easy at all ! So everything
    depends on the specifications... If a phase noise as high as the carrier
    some tens of MHz away is fine, and if a phase lock is not needed, then it is
    quite easy...

    Robert Lacoste
  11. Ben Pope

    Ben Pope Guest

    Fred was talking about payam, not you.
    You really should learn to comprehend what you read. I have no form of
    xenophobia, nor did I say anything of that sort.

  12. Ben Pope

    Ben Pope Guest

    Both titles are for signal/spectrum analayzer, yet refer to the NI PXI-5660
    Sig Gen (if indeed, thats what it is)
    Indeed. We can all make a noise, but as to whether it's useful or not is
    something else.

    I can sit here (well... in the kitchen) and press the gas hob sparky thing
    to make broadband noise possibly including GHz frequencies but I'd be hard
    pushed to do anything with them. Other than light the hob or give myself a
    shock, obviously

    I'm assuming his posts are regarding signal generation, propogation and
    presumably reception at x-ray and gamma frequencies (re his other posts over
    the last week or so).

  13. SioL

    SioL Guest

    That was indeed ment for Fred, I know him well from his previous xenofobic
    rants, which is why he is in my Ctrl-K. I'm sorry if a few schrapnels got you as well :)

    Yes, I agree, it all depends on what this guy really needs. It may be viable if his
    requirements are not high.

  14. Ben Pope

    Ben Pope Guest

    It happens...

    As far as I can gather, he's a student, and it's his choice of project. I
    guess he'll learn KISS the hard way if he insists on this line of

    payam: KISS means Keep It Simple, Stupid. It's a well known engineering
    principle. You'll get a better mark for doing something well than
    attempting and failing.something hard. Bring yourself down a good few
    orders of magnitude in frequency and you'll be fine.

  15. SioL

    SioL Guest

    Yeah, how about MAX038 for a start?

  16. Ben Pope

    Ben Pope Guest

    Hehe, 3 orders of magnitude... perfect. Kind of cuts his project down to
    the bare essentials... Single chip COTS solution. :)

    A* for development cost.


  17. Fred Bloggs

    Fred Bloggs Guest

    The word is xenophobic, you good for nothing eastern european trash, and
    you're wrong about that- please visit the US so we can make you a
    permanent part of the landscape.
  18. I'm going to disagree here ... as a former electrical engineering
    instructor at the University of Michigan ... we rewarded *some*
    attempts at very difficult projects, as long as there was a partial
    success, and the students had done the work themselves. I recall one
    group of students in my class in 1986 ... they built a rather nice TV
    receiver - Lo VHF only. There wasn't enough time to finish the
    display, so they wired it to the X,Y and Z inputs of the laboratory
    scope. I saw a crude picture, and gave them an "A".

    The KISS principle belongs to engineering ... not always taught at the
    academic level, even though I agree it should be. In the real world,
    there ARE designers needed for spectrum analysers and RF generators.
    There's nothing wrong with getting started early.

    SIOL - thank you for posting the link from Matjaz Vidmar. That is a
    very nice summary of VCO design.

    payam - Another source I have found helpful:
    "Microwave Circuit Design Using Linear and Nonlinear Techniques"
    by Vendelin, Rohde. (and third author I forget, since I lent it out)

    Frank Raffaeli
  19. Ben Pope

    Ben Pope Guest

    Well thats fine. But if somebody attempts something that is clearly outside
    of their reach, expecting to have it all finished and working then they're
    doing something wrong. Obviously getting somewhere with a difficult project
    is great, but as I'm sure you're aware you really should have some idea of
    whats possible within your constraints before starting it. All engineering
    projects start with a feasability study...
    True, but the MHz range would be a better place to start playing with HF
    design than GHz, surely.

    I wish the guy luck - I've learnt the hard way that biting off more than you
    can chew usually ends in disappointment - I suspect that I'm not the only
    person here. I'm guessing that this is one of the first practical projects
    of this size that the guy has undertaken and also the first thing he's tried
    in HF design. He WILL underestimate the amount of time it'll take him.
    Probably by a factor of 3 or more.

  20. Hmm ... I don't think I feel qualified to determine if it's out of his
    reach. After all, his questions on all the other threads sound like
    something I would have asked 30-35 years past, and I turned out okay
    It's only 2.7 GHz, IIRC. Lathargic ... close to D.C. I'm envious. Back
    when I was in college, they didn't have such devices as they do today
    .... so easy to match and use at low GHz ranges.
    Having a few failures behind him will certainly improve his outlook,
    not dash his dreams, IME. Trying projects beyond one's ability is the
    mark of a person who will learn rapidly, IMHO.

    Whatever discouraged you in the past, it sounds like you have had some
    experience since. I realize you are trying to be pragmatic, but the OP
    is just looking for advice on a spectrum analyzer circuit, I presume.
    It's not that complicated.

    Frank Raffaeli
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