That's correct. I work hard at what I do, but I'm always on the lookout for mistakes I may make, or more often, things I don't yet understand. Hopefully I'll not pipe up about something I don't yet understand, but oops, oops, sometimes one doesn't yet know that they don't understand something, or they may just make a silly thoughtless mistake.
--
Thanks,
- Win
There's no point in arguing definitions. The circuit does what it does. I used AGC to mean that there's an amplitude detector that compares the output swing against a reference and feeds back on a circuit parameter (transistor transconductance in this case) to servo the amplitude to a target. AGC works that way. So does ALC. I suppose ALC is used when the servoing is more precise. The circuit does what it does, which is make amplitude-stable, amplitude-predictable sine waves. It's not stunning, but it is sort of cute. And it does make one think about what *does* limit oscillation amplitude. [1]
If JT thinks it works some other way, he sure hasn't said how. All he's done is tell us how dumb we are.
And yes, "discussion" suggests some amount of uncertainty and exploration of ideas. JT and JF and AlwaysWrong and Sloman are way too fragile to play that game.
John
[1] jfet oscillators sometimes amplitude limit by means of the gate junction peak-rectifying the AC signal there, and back-biasing themselves more negative as the amplitude increases. That's a lot softer feedback mechanism than my bipolar thing.Here's a cute crystal oscillator:
+------ to ttl gate input | | d +------g jfet | s xtal | | | | | gnd gnd
And circuit design tools as well.
[snip] [snip jerkism]
YD is normally blocked. Since JL responded...
I will, in due course. I'm waiting, and hoping, that some young buck has a clear head, and can analyze it. ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
My first real job was a research assistant in microwave spectroscopy, a summer tech job. Two grad students on the same project spent the entire summer hunched over a Friden calculator in a small room, calculating rotational resonances for some organic thing. My PC could do all that now in, probably, a millisecond.
It is just about the only portable schematic format the industry has ever seen. Not a bad editor, but the circuits seem to wander all over the screen as you zoom. I have to keep selecting my whole circuit and dragging it back into sight.
John
You're wrong John. And I've got your ass this time :-)
Unfortunately Win doesn't understand how the oscillator works either. Disappointing :-( ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
What would determine the sinewave amplitude?
John
Yep. "Ooopses" happen. As soon as I describe it on Sunday or Monday, you'll see how simple it is to understand.
Off to SFO at dawn... NO I'm not seeing Larkin... I'm heading to Palo Alto ;-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
I passed it to you, not to "rag" on you, but to have a "father figure" show Larkin the error of his ways.
But you didn't do it :-( ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
Larkinese: "There's no point in arguing definitions. The circuit does what it does. I used AGC to mean that there's an amplitude detector that compares the output swing against a reference and feeds back on a circuit parameter (transistor transconductance in this case) to servo the amplitude to a target."
Larkin can keep jockeying, trying to find a way to weasel into "correct". However, the paragraph above, direct quote from Larkin is WRONG.
The circuit does indeed oscillate, and control amplitude... but not as Larkin opines. It definitely doesn't function as he claims.
Isn't there some young buck out there who can analyze circuits ?:-( ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
I don't appreciate being thought of as a father figure.
But so far as the circuit goes, I've thought about it a bit and feel comfortable with my understanding, so far.*
It'd be nice if you'd state your point, rather than making endless disparaging remarks. Do you like thinking about signal-current pathways, rather than voltage gains, OK, great, I like that too, spell it out. We'll take a look.
Have you considered that while you may have a specific concept in mind, there may be other ways to adequately express the same phenomenon?
--
Thanks,
- Win
Late at night, by candle light, John Fields penned this immortal opus:
I'm speaking to Jim, not his side-kick.
Could be "The Three Jays" too.
-YD.
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Late at night, by candle light, Jim Thompson penned this immortal opus:
EXCELLENT!!! I can bad-mouth the silly old bastard to my heart's content and he'll never be the wiser.
Instead of a kill list I use a watch list, for grabbing the bodies of posts by people who usually are on topic. I had to take JT off it due to his political spamming and general negative attitudes.
-YD.
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Hi Jon, I hope you=92re not offended if I say that the first time I read this I thought it sounded crazy.
I took vol. 2 of =93The Feynman Lectures of Physics=94 down to the creek when I got home this evening. In chapter 36 he does ferromagnetism. (do you have a copy?) He does an electro-magnet near the end. (36-5). Early in the chapter he says that if you are willing to accept the fiction of magnetic monopoles, you can think of ferromagnetism as the magnetic analog of the polarization of dielectrics.
And so I totally accept your picture=85 though I understand it differently. Thanks!
Oh Feynman says the energy loss is the area enclosed by the B/H curve.
George H.
Bad choice of words, I guess ;-)
When I was in my forties I had sweet-young-thing (female) employees who said I was a father figure to them :-(
I only meant that, since Larkin side-steps me like the plague, and calls me "cranky ol' git", I thought he'd listen to you.
Hint before I run out of town for a few days: replacement energy.
I _will_ write it up upon return. It's really quite simple... at least fundamentally... you can get crazy performance by pushing the turns ratio.
Hint #2: What does transconductance have to do with a large swing oscillator? ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
Maybe, but your pc doesn't drink beer or chase cute college girls. ;-)
-- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
ime
Or
ts
sng
That's cool, so at a year and 1/2 I'm not that far behind. (Well I've only been doing circuit design for ten years...Still way behind)
George H.
A lot depends on how fragile your ego is. If you are determined to always be "right" in public, or you are determined that someone else is always wrong, you'll be a fathead and not learn anything.
Of course, there are some people who are AlwaysWrong.
John
There was an explanation of the operation of a similar type of oscillator in Electronics World (formerly Wireless World) by Ian Hickman in the July issue. It is also in the book "Hickman's Analog and RF circuits). The circuit analyzed there is a Hartley oscillator with the feedback into the base but that is only a minor difference as one can be changed to the other by redefining where ground is.
As the oscillation amplitude increases the cb junction becomes forward biased and that does a couple of things; not only does it divert base current but through reverse transistor action causes the resonant circuit to be clamped, dissipating energy. Also it reduces the conduction angle where energy is added to the resonant circuit by splitting the current into two pulses - a balance then results when the energy added each cycle is equal to the energy lost.
kevin
:-) ...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |
The only thing bipartisan in this country is hypocrisy
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