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how to design a transmitter

Discussion in 'Electronic Design' started by feilip, Nov 1, 2004.

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  1. feilip

    feilip Guest

    Hi,

    I am new in designing circuit using off-the-shelf component. Would
    anyone pls give me some insight?

    I just wonder what is a typical design steps if I use a transmitter
    chip, such as, Texas Instruments TRF6900, to build a transmitter. Do I
    simulate the chip with external passive components in some software
    such as Agilent ADS?

    Thanks for your help.
     
  2. Sounds like you're trying to get in at the deep end. RF is not the
    place to start designing anything!
     
  3. Joerg

    Joerg Guest

    Hi Paul,
    Oops. RF is how I started my foray into electronics as a kid. Should I
    stand in the corner now, repent and feel ashamed?

    Regards, Joerg
     
  4. No, you just have to start all over again ;)
     
  5. Same here. But I'm talking about RF *design* which I assume as a
    child, was beyond you, as it was me (and I *still* have a lot to learn
    x decades on).
     
  6. Joerg

    Joerg Guest

    Hi Paul,
    That's right, at first it was building stuff found in books at the
    library. But around age 14 I started to redesign things. When I wasn't
    happy with the IF filter of my old tube radio I made my own, then added
    another oscillator so I could listen to single sideband, then made an
    even narrower filter to catch distant CW stations. This is when I
    discovered that toroids make a much more stable resonant circuit than
    those old coils in the aluminum cans. Of course RF in those days was all
    below 30MHz so things were a lot easier.

    The math was the most excruciating job back then. We didn't have
    calculators. When my father gave me his slide rule calculator I was
    jumping with joy. That cut the job almost in half. It let me calculate
    back and forth until I could build it with capacitors that I had. Else
    it would have been an hour round trip to the store in town.

    Regards, Joerg
     
  7. Reg Edwards

    Reg Edwards Guest

    But I'm talking about RF *design* which I assume as a
    ========================================

    Once having learned the relatively few basic electrical principles, and how
    to do arithmetic, with practice on the bench you know it all. Then all
    that's needed as an aid to thought are the manufacturers' components and
    chip catalogues.

    But those unfortunates who were too lazy to learn arithmetic, or were
    frightened away from it by ill-educated, unimaginative primary school
    teachers, will remain seriously handicapped for the remainder of their
    working lives.
     
  8. <boggle!>
    It's a bit more involved than *that* Reg!
     
  9. Reg Edwards

    Reg Edwards Guest

    Once having learned the relatively few basic electrical principles, and
    how
    =====================================

    Dear Paul,

    Like your contemporaries and products of the educational system, you
    over-complicate matters. Looking in advance for problems where none probably
    exist. Which signifies a degree of lack in self-confidence.

    Who needs Kirchoff and the other theorem writers? Myself I've hardly ever
    heard of Kirchoff except in these newsgroups. If you want to convince me in
    a technical argument, quoting Kirchoff or Terman is wasted effort. I doubt
    if it convinces others.

    When was the last time Kirchoff or Terman ever solve one of your (or anybody
    else's) genuine PRACTICAL problems?

    Things worked out OK for me. But then, I take a different viewpoint - I'm
    self-educated. Beyond reading and writing up to the age of 14 I am not a
    product of the 40-years debased UK technical educational system.

    I'm sure you appreciate I have not the slightest ill-will against your
    only-to-be-expected views. But you may wish to take into account that I have
    just consumed a bottle of cheap plonk - a claret.

    Ah, if only politicians could maintain such an amicable degree of accord
    instead of just calling each other names for the presidential cheer-leaders
    to automatically repeat.
     
  10. Ken Taylor

    Ken Taylor Guest

    Geez mate, a Pom, a claret and a keyboard! Slap my dingo with a didgeridoo
    but I'm buggered if I can think of a more lethal combination!

    Having said that, the OP could well do what Reg is saying and get a copy of
    the RSGB and/or (preferably and) ARRL handbooks and going at it. The man who
    never made a mistake never made everything. Sorry, anything.

    Ken
     
  11. Joel Kolstad

    Joel Kolstad Guest

    Like your contemporaries and products of the educational system, you
    You have a point in that people who concentrate too much on the academic
    aspects of engineering can sometimes lose sight of the need for solving real
    world problems, and I'd even give you that a very large percentage of
    electronic devices out there can be designed with just 'a few basic
    priciples and lots of bench experience,' but there are also plenty of areas
    where those alone won't suffice -- even determining the the values of the
    components in a 'simple' pi filter, for instance. A more complex example
    would be the design of the codecs in cell phones -- they are FAR from
    trivial.

    What happens is that you make a choice as to how much of a 'system
    integtrator' you want to be vs. a true 'designer.' Or, perhaps so as not to
    make such an arbitrary division, you make a choice as to whether your design
    in on... the product level... the module level... the component level... the
    chip level, etc. As you move to higher levels, 'common sense' becomes more
    and more all that is needed for success. Perhaps ironicially, it's at those
    higher levels that more jobs exist!

    ---Joel Kolstad
     
  12. You're undoubtedly right; certainly in matters electronic, anyway.
    I assume you mean Thevenin? His is a useful way to visualise some
    basic resistance/impedance stuff. I do resort to it quite frequently.
    Kirchoff, very much less so.
    In vino veritas, Reg; in vino veritas.

    I have grave doubts that I'm cut out for higher electronics. I can't
    see things the way you intuitive types can (could the skill be
    cultivated somehow?) My natural talents lie in other areas but
    electronics is a life-long interest and I'd like to do a little better
    at it than I do!

    Any tips and suggestions readily welcomed!
     
  13. Joerg

    Joerg Guest

    Hi Paul,
    So what is cheap plonk? The category "mise en bouteille dans notre garage"?

    Regards, Joerg
     
  14. Rich Grise

    Rich Grise Guest

    WTF is "higher electronics?" There's electronics, and there's stuff that's
    not. :)
    'tain't necessarily so! It isn't really "intuitive," it just seems like
    it after embedding oneself in it for some time. :)

    (could the skill be
    I wouldn't worry about the "talents" a lot of us have a lot of different
    talents. If you're interested, that's really all the motivation you need,
    and it keeps it fun as a hobby. :)
    Get a meter and a soldering iron and some parts and a proto-board or
    one of those 101-in-1 kits, and read a lot. I always used to hang out at
    621.384 in the Library. :) And I think the book that I knew as "The
    Radio Amateurs' Handbook" goes by a different name now, and I'm sure
    that someone will help out here. A lot of people say a lot of good
    stuff about AoE, but I can't speak at that, other than that I highly
    respect Win Hill and am consistently impressed with his knowledge
    and the way he presents it.

    Have Fun, and welcome to the snake pit! ;-)
    Rich
     
  15. Max Hauser

    Max Hauser Guest

    "Paul Burridge" in news:...
    (I would suppose more likely Tellegen than Thévenin in this context) but to
    defend poor Herr Kirchhoff, for what it's worth: I for one spend all day
    solving what many would call practical electrical problems and I make use
    often of Kirchhoff's two handy laws for voltage and current (affectionately
    KVL and KCL), they are foundations on which you can build an analysis of a
    circuit if you really need to know what it does. I use these things as part
    of my tools, just as in the lab I would use a trusty DVM or spectrum
    analyzer or screwdriver.

    Regarding good old red plonk, if anyone doesn't know this, alt.food.wine is
    now a very constructive wine newsgroup; helpful discussion of all styles and
    price levels.

    Cheers -- Max
     
  16. Shouldn't that be *une* bouteille? ;-)
     
  17. Thanks for the encouragement, Rich, but I did all that in the late
    60's! I'm convinced it's a problem with the way I look at things. I
    often overlook the obvious, simple solutions and see things as far
    more complicated than they are. Occasionally, of course, they *are*
    actually more complicated than they seem. But I can't tell which is
    which! :(
     
  18. Tony

    Tony Guest

    I use Kirchoff's laws quite regularly to trace backwards through new
    circuit topologies I come up with (typically filters). It's easy to
    simulate, them, but nothing replaces a transfer function to see the
    dependencies etc. And Thevenin almost as regularly to analyse larger
    circuits. One can get by with application notes, memory etc, but
    without these very basic tools one's really restricted to reproducing
    what has gone before, rather than anything new.

    Tony (remove the "_" to reply by email)
     
  19. 1) Work out what you want to do. (A mission Statement).

    2) Work out what you *need*, in function blocks, in order to do what you
    want to do :). (Requirements Gathering).

    3) Find out if there is something in the market that (mostly) does this.
    (Search for an existing solution).

    ....This is where you are now, rite?

    4) Find out who the supplier is and especially if you can actually *obtain*
    the device *now*. (Debunk blatant vendor Lies).

    5) Get the data-sheet, any application notes, errata etc. on the device.
    Especially take note of any warnings in the application notes that the
    designers managed to slip past Sales and Marketing such as recommended
    layout and power supply decoupling; if it's there, somebody stuck their neck
    out for you and they really mean it. (Gather design information).

    6) Build the circuit closest to your application from the application note -
    or get an evaluation board if it is available. (Design, Debunk more lies).

    7) Work out what is wrong with the application circuit. (Test, debunk yet
    more lies).

    8) Then add the missing functionality and fix the broken features. (Debug,
    Test, Design, Verify).

    8a) Then find out that the device is now on Last Order By ... status ;-{
    8b) You are actually done.
    Easier to get the application board, if any, or just build the device
    outright. Simulation of complex mixed analog/digital devices is often hairy
    and difficult to verify properly anyway - often it is faster just to build
    the prototype and measure on the real thing.
     
  20. Rich Grise

    Rich Grise Guest

    Well, that's about all I had. )-;

    Have you done all the standard "blow stuff up" experiments? ;-)

    Good Luck!
    Rich
     
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