Random comments on common errors in technical documents
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MarcelvdG
diyAudio Member

Join Date: Mar 2003
Location: Haarlem, the Netherlands
Quote:
 Originally Posted by DF96 Possibly. I think UK EEs generally extend 'linear' to include 'affine', as 'affine' is not a word which crops up often on EE courses here. 'Linear' is taken to mean 'no new frequency components in the output'. Interestingly, the strict definition of linear excludes all sources (e.g. DC PSU, AC oscillators) so may be mathematically correct but perhaps unhelpful?

Strictly speaking, if there is no DC at the input but there is DC at the output, you have a new frequency component namely 0 Hz.

Anyway, an affine circuit can usually be split into a linear circuit and a bunch of independent sources. Superposition applies to the linear circuit, so you can turn on each independent source in turn and add the resulting output signals. I don't see what's the problem with that.

scott wurcer
diyAudio Member

Join Date: Jan 2004
Location: dorchester ma
Quote:
 Originally Posted by MarcelvdG -In the context of current feedback op-amps it applies to the exact same feedback configuration as normal voltage feedback (shunt at the output, series at the input), but with an op-amp having a low open-loop input impedance at its negative input.
IMHO this captures very poorly one fundamental property of CF op-amps, the closed loop BW to the first order does not change with gain. If the closed loop equations are rearranged to isolate the current into the inverting input things are very clear by considering that that current as what is fed back.
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 6th July 2012, 09:36 PM #103 MarcelvdG   diyAudio Member   Join Date: Mar 2003 Location: Haarlem, the Netherlands Hi Scott, I'm not denying that having a low open-loop input impedance at the negative input can have practical advantages, such as the one you just explained. All I'm saying is that three totally different feedback configurations are all referred to as "current feedback" because the term has been redefined at least twice. That doesn't make it any easier to understand what is meant. Best regards, Marcel
Ron E
diyAudio Member

Join Date: Jun 2002
Location: USA, MN
Quote:
 Originally Posted by jlsem I once read a technical paper by a well-known and respected Ph.D. who posts often on these forums and he didn't seem to know that a loose cite was not the same as to lose sight.
I read a book, possibly by the same phd, that reversed form and from so many times that it made your head spin.
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7n7is
Banned

Join Date: Mar 2006
Location: VA
There's a serious problem here.

Quote:
 The Streptomycin was invented by Selman Waksman and received patent number 2443485 on June 15, 1948.
When was the Streptomycin invented?

The patent given is on streptothricin not streptomycin.

 8th July 2012, 11:26 PM #106 willysan   diyAudio Member   Join Date: Dec 2005 Location: Buenos Aires In the previous page I spotted "it's" where the the author meant "its".
Wavebourn
Designer & Technologist
diyAudio Member

Join Date: Sep 2006
Location: Pleasant Hill, CA
Quote:
 Originally Posted by Ron E I read a book, possibly by the same phd, that reversed form and from so many times that it made your head spin.
Wehn you quickly raed mispyted txet olny frist and last lettres mettar. That's why ancient people used hieroglyphs to communicate meanings instead of sounds.
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Last edited by Wavebourn; 9th July 2012 at 12:29 AM.

popilin
diyAudio Member

Join Date: Oct 2010
Location: Traslasierra
Quote:
 Originally Posted by jlsem I once read a technical paper by a well-known and respected Ph.D. who posts often on these forums and he didn't seem to know that a loose cite was not the same as to lose sight.
Tell us who is

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Shaun
diyAudio Member

Join Date: Aug 2001
Location: Cape Town, South Africa
Quote:
 Originally Posted by Pano And the worst one of all, the eternal "And I" mistake. Seems that so few people in America can get that one right that it's going to have to change. Stupid, but that's the way it is. It seems we have a generation or two of English teachers that has failed us. "And I" or "And me" - how hard can it be?
Let's explore that. When do you use the one or the other? I do believe that we have been taught to use "and I" at all costs.

The way I figure it out is use whatever you would have used had the other person(s) not been included.

Jack and I went to the shop. (I went to the shop)
The shopkeeper stared at Jack and me. (The shopkeeper stared at me)
Not Quickly he handed the goods to Jack and I. (Quickly he handed the goods to I)

Also, I've never been told this or read it anywhere (that I'm aware of), but I believe the correct form is to refer to yourself last (not "me and Jack").
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 9th July 2012, 09:34 PM #110 DF96   diyAudio Member   Join Date: May 2007 Shaun and I agree on this.

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