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RFDesign Magazine article--Tayloe

Discussion in 'Electronic Design' started by amdx, Jul 20, 2005.

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  1. amdx

    amdx Guest

  2. Jim Thompson

    Jim Thompson Guest

    Sheeeesh! The things they'll patent as soon as people forget the
    masters...

    Franks, L.E. and I.W Sandberg: An Alternative Approach to the
    Realization of Network Transfer Functions: The N-Path Filter, BSTJ,
    vol. 39, pp. 1321-1350, September, 1960

    and for the practical application...

    ANALYSIS AND DESIGN OF INTEGRATED CIRCUITS, Motorola Series in
    Solid-State Electronics, McGraw-Hill, 1967, (before ISBN), Chapter
    15, "Frequency-Selective Amplification Without Inductors"

    ..... written by yours truly ;-)

    ...Jim Thompson
     
  3. Joel Kolstad

    Joel Kolstad Guest

    Indeed. I think a lot of people (including myself) come up with the idea
    behind the Tayloe detector independently... and in my case I can attribute it
    to some Forrest M. Mims book I read back in the '80s (he was applying the idea
    to modulators instead of demodulators though)...

    Further discussion of Tayloe's detector not being all that horribly new:
    http://www.arrl.org/tis/info/pdf/030304qex020.pdf

    ---Joel Kolstad
     
  4. I've been out of the receiver design game for about fifteen years,
    concentrating on audio processors and some other stuff (like keeping at
    least a week ahead of my college students).

    Tell me, in a VHF AM double sideband world, how do you implement a zero-IF
    receiver? Seems to me that if the on-frequency "local oscillator" needed to
    be spot on the carrier drifted just a few hundred Hz. that it would show up
    in the detected signal as a howling audio tone. I guess you could implement
    a phase-lock arrangement of some sort, but phase locking to submicrovolt
    signals ain't all that trivial.

    At this point, just of academic interest, but I hope to retire out of
    academia next year and would really like to get my hands back on the design
    bench. It's been too long ...

    (So? What was WRONG with the 6U8 mixer design?)

    Jim
     
  5. In a receiver, it's better to decimate against a frequency that brings
    the image down to a low IF, rather than a zero I.F., to avoid the DC
    offset issue and to improve the dynamic range of the detector. In this
    case, the absolute value of the IQ vector sum (after low-pass
    filtering) is the AM demodulated output. For phase demodulation, the
    offset must be subtracted from the result.

    For a transmitter, offset is introduced for a different purpose,
    usually to prevent injection locking of the VCO with the modulated
    carrier.

    Frank Raffaeli
    http://www.aomwireless.com/
     
  6. Joerg

    Joerg Guest

    Hello Jim,
    They employ two balanced mixers in an I-Q structure. Sounds easier than
    it is in reality. In theory none of the LO energy gets out. In reality
    some does. Then it produces the effect you mentioned or, worse, gets
    modulated and re-radiated somewhere and then brings in a nice 120Hz rattle.

    Here is a paper on it:
    http://print.google.com/print/doc?articleid=k5HdiBsrG63
    Nothing wrong with these, except that right now I am happy that there is
    no tube heating up the office. I don't like AC in there so it's a cozy
    96F. The ECC81 was my favorite and you could make a nice balanced mixer
    with these. With a dynamic range from here to Alaska.

    Regards, Joerg
     
  7. Joerg

    Joerg Guest

    Hello Jim,
    Many patents seem to be written to build a thick portfolio. When
    drilling down the claims it often takes less than 1/2 hour to find
    serious prior art that would potentially blow it out of the water.

    Regards, Joerg
     
  8. What means "decimate"???




    against a frequency that brings
    Well, shucks, that's just a single conversion superhet.


    In this
    Are you saying then to use a zero-IF to detect the first IF?

    Jim
     
  9. Andy

    Andy Guest

    Andy writes:

    This reminds me of a dozen years ago when I was an
    engineer at Texas Instruments.... I was on the Patent
    Committee , and it was our job to review the NUMEROUS
    invention disclosures that were submitted by several
    hundred engineers in order to determine which ones
    would be useful to the company to file.....

    Much of the time, the "invention" would be something
    that one of us had used 20 years before, and could now be
    bought from Digikey or Newark for a couple dollars from
    their catalog........ These , of course, were not approved
    for filing, and caused great disappointment to the
    inventors, who were very proud of their GREAT IDEA....

    In fact, most of the ideas were GOOD IDEAS, .... it's
    just that someone else had them before, and , while that
    doesn't diminish the intellectual kudos for the new inventor, it
    did mean that filing for a patent was of no use, since it was
    prior art...... You need a lot of old-timers who are also
    electronics hobbyists on a patent committee to weed out this
    stuff......

    So, let's don't "dis" Mr Tayloe -- he had a good idea, and
    may have come up with it on his own...... Just like the
    other guy did 20 years ago...... It shows he is a , thinking,
    innovative person....... sometimes you eat the bear, sometimes
    the bear eats you....

    Andy

    PS My first patent application, ( a half century ago ) was
    for a T notch filter which used a transistor as a feedback emitter
    follower. It was denied because, 30 years earlier, a fellow
    had done the same thing with vacuum tubes........
    I was disappointed, of course, since a person's "first " patent is
    the one which validates his personal sense of innovative
    genius. I recovered, and had a nice career in spite of
    it..........
    .......... end of nostalgic reverie ........
     
  10. Joel Kolstad

    Joel Kolstad Guest

    You take a stream of numbers and insert a bunch of zeroes inbetween them. :)

    Seriously, that's what you do. It 'squishes' (compresses) the frequency
    response... see something like section 9 of www.analog.com/UploadedFiles/
    Tutorials/450968421DDS_Tutorial_rev12-2-99.pdf, your favorite DSP book,
    Google, etc.
     
  11. Jim Thompson

    Jim Thompson Guest

    [snip]

    I was on Motorola's and GenRad's patent committees.
    I have that as a wood placque over my office door ;-)
    I've only had one patent application where the examiner tried to deny
    it. I replied he was too dumb to understand the concept. He then
    allowed it ;-)

    ...Jim Thompson
     
  12. Joerg

    Joerg Guest

    Hello Andy,
    My personal sense of innovative genius gets validated when the client is
    happy, made money with it, and I made money with it ;-)

    Regards, Joerg
     
  13. keith

    keith Guest

    I've served on one of these "boards" for twelve years. It's quite
    interesting to see how inventors think. It's also quite interesting to
    see what motivates the best of them. It's not what I would have expected
    a decade ago. ;-)
    Wooden plaque! Ick! Does your dentist know?
    Times have changed. Now they're all too dumb, but must reject them
    anyway. The USPTO is now a government profit center and rejections
    make them more money (think: performance reviews).
     
  14. adding zeros and lowpass filtering is upsampling or interpolation, lowpass filtering
    and removing sample is downsampling or decimation ....


    -Lasse
     
  15. yep, I know atleast on company very much encourage employes too try a get patents
    on pretty much anything they can come up with to meet they annual gold of filing
    atleast as many patents as the competition and give bonuses for every patent filed...

    -Lasse
     
  16. Ben Bradley

    Ben Bradley Guest



    My name is on two patents, and other than actually contributing to
    the design covered by the patents, I had very little to do with it (If
    that sounds clear as mud, I hope my explanation below clears it up).
    I'm sure I'm a thinking, innovative person, unfortunately that has
    little to do with my name being on these patents.
    My employer at the time, a quite large company, said they wanted
    another patent (which quickly became two patents), and it was going to
    be on the product I was co-designing. The managers talked to the
    patent attorney, then tje attorney talked to the other engineer and me
    for a couple of hours, asking us about the operation of the areas to
    be covered by the two patents. What was being applied for had already
    been determined by the managers. Between the other engineer and
    myself, there were about half a dozen OTHER parts of the circuit or
    methods of operation of the device that we would have chosen one or
    two to be patented (had we been asked). We would not have thought of
    what was being proposed for the patents.
    But to management it wasn't so much about protecting innovative
    ideas as it was about the company cutting out as big a turf of IP as
    it can for each patent, so that it is more likely to find competitors'
    products infringing. As was explained to me, this is done as much in
    defense as in offense: If another company finds one of our devices
    infringes, if we have enough patents so that we can find where they
    infringe one of ours, we can cross-license the patents to each other
    and go on like nothing happened.
    A few months later the attorney sent a draft of the application for
    us to comment on. We changed a couple sentences and sent it back.
    About a year or two later I got this blurb in the mail saying
    "Congratulations! For only $65 you can get the first page of your
    patent application with the date it was approved on this extra-nice
    plaque!" A couple months later I learned the same way that the second
    patent was approved.

    Before all this happened, this company had a seminar on patents,
    describing some of the ones they had, from the usual things to
    business method patents. The one I most remember was where an engineer
    patented the addition of a resistor to a circuit when this was
    obviously not a big innovation - he was telling his manager he though
    it would be approved, the manager didn't think so but let him apply
    for it, and of course it WAS approved.
    So yes, you CAN get a patent on virtually anything, but of course
    enforcing something like that is another matter.
     
  17. Terry Given

    Terry Given Guest

    ISBN: 0070417237
     
  18. Fred Abse

    Fred Abse Guest

    You are well known for your modesty, Jim :)
     
  19. I also went looking for the figures (pretty sure it was the same
    article). Dan Tayloe was good enough to send me an earlier manuscript
    - I think I found him on rec.radio.amateur.homebrew.

    Steve Kavanagh
     

  20. I prefer: "We all have our bears to cross!" ;-)

    --
    Link to my "Computers for disabled Veterans" project website deleted
    after threats were telephoned to my church.

    Michael A. Terrell
    Central Florida
     
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