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John Woodgate
Guest
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 Posted:
Mon Feb 07, 2005 2:34 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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I read in sci.electronics.design that martin griffith
<martingriffithX@yahoo.co.uk> wrote (in <e4uc01tgs0n07voisfqm2qkbp3hm1m0
mll@4ax.com>) about 'Lookinf for options for an Absolute Magnitude" or
precision rectifier circuit.', on Sun, 6 Feb 2005:
| Quote: | On Sun, 6 Feb 2005 08:12:52 +0000, in sci.electronics.design John
Woodgate <jmw@jmwa.demon.contraspam.yuk> wrote:
Unfortunately, the kid
wouldn't let me steal it to see in detail how it works. (;-)
tut,tut, stealing from little children, maybe you should go into
politics or religion
I said I DIDN'T steal it. Maybe YOU should go into politics or |
religion.(;-)
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
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Winfield Hill
Guest
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| Posted:
Mon Feb 07, 2005 2:58 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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Jim Thompson wrote...
Yes it's ugly, but probably works fine, provided it's DC coupled...
The input stage safely draws a fraction of a mA for negative voltages
(see fig 3) but is OK; the other opamp works fine inverting the signal.
But I doubt this circuit can do well at low voltages. I have another
configuration I prefer for mV-level active rectification, which even
works well at MHz frequencies.
--
Thanks,
- Win |
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Fred Bloggs
Guest
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| Posted:
Mon Feb 07, 2005 3:05 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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John Larkin wrote:
| Quote: | On Sun, 06 Feb 2005 15:21:42 GMT, Fred Bloggs <nospam@nospam.com
wrote:
John Larkin wrote:
Crazy! It pulls the opamp input below ground, in violation of
their own abs-max ratings! That 2 volt p-p input must be on the
very edge of blowing the opamp up.
In addition to knowing nothing about the 291, you can't read- the
AM Rating was obviously intent on saying GND+/-10V,
ABSOLUTE MAXIMUM RATINGS 1, 2 Supply Voltage . . . . . . . .. . . . .
. . 16 V Input Voltage . . . . . . . . . . . . . . . GND to VS 10 V
Is that what "GND to VS 10V" means? It looked like a misprint of "GND
to VS+10V" to me. I admit I didn't study the entire datasheet, this
being a newsgroup and I having real work to do of my own.
Why can't people proof datasheets?
Never mind- will not waste time on that individual...
Oh, please don't waste any of your valuable time on any of us.
|
I see now that we were crediting the fascist with far too much
observational ability- all he was doing was SPICE simulation, and the AD
model does not begin to model input overdrive accurately- producing
phase reversal at ridiculously low overdrive. So the idiot hasn't even
gotten to square one- what a pathetic little loser- all he was doing was
looking a signal shapes and noticed a sine thingie where output should
be flat lined- my, my, my, what a stickler for detail he is! Why is it
all you Nazi types are so damned stupid....
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Jim Thompson
Guest
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| Posted:
Mon Feb 07, 2005 3:25 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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On 6 Feb 2005 12:58:21 -0800, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:
| Quote: | Jim Thompson wrote...
http://www.analog.com/UploadedFiles/Data_Sheets/813995969OP191_291_491_c.pdf
On page seventeen!
What a crock! Relies on rail-to-rail OpAmp with negative rail of
first stage tied to ground :-(
Yes it's ugly, but probably works fine, provided it's DC coupled...
The input stage safely draws a fraction of a mA for negative voltages
(see fig 3) but is OK; the other opamp works fine inverting the signal.
But I doubt this circuit can do well at low voltages. I have another
configuration I prefer for mV-level active rectification, which even
works well at MHz frequencies.
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Can we see that configuration?
(On custom I/C's I usually use multipliers to measure low-level RF.)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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John Larkin
Guest
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| Posted:
Mon Feb 07, 2005 4:06 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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On Sun, 06 Feb 2005 21:05:24 GMT, Fred Bloggs <nospam@nospam.com>
wrote:
| Quote: | I see now that we were crediting the fascist with far too much
observational ability- all he was doing was SPICE simulation, and the AD
model does not begin to model input overdrive accurately- producing
phase reversal at ridiculously low overdrive. So the idiot hasn't even
gotten to square one- what a pathetic little loser- all he was doing was
looking a signal shapes and noticed a sine thingie where output should
be flat lined- my, my, my, what a stickler for detail he is! Why is it
all you Nazi types are so damned stupid....
|
Usenet was apparently invented as the medium for proving that Fred is
smart and everybody else is stupid.
Right now, I'm writing the self-test code for the B-52 bomber radar
thing, which is a real drag. So, tell us about something cool you're
working on now and make us jealous.
John |
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Clarence_A
Guest
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| Posted:
Mon Feb 07, 2005 4:43 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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"John Larkin" <jjSNIPlarkin@highTHISlandPLEASEtechnology.XXX>
wrote in message
news:aisc019r90e95v4mcrppq7b8our1ap7ktq@4ax.com...
| Quote: | On Sun, 06 Feb 2005 16:35:14 GMT, "Clarence_A" <no@No.com
wrote:
Since I need to change what the "app note paste artist" put
together, I need to refute his premise that "it wouldn't be
published if it wasn't correct."
Ha! Read the "ideas for design" clips in ED or EDN. Typically
nonsense.
John
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You mean it "ISN'T" a joke? (:>) |
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Clarence_A
Guest
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| Posted:
Mon Feb 07, 2005 4:53 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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"richard mullens" <mullensdeletethis@ntlworld.com> wrote in
message news:pcuNd.2782$KE2.39@newsfe3-win.ntli.net...
| Quote: | Clarence_A wrote:
"richard mullens" wrote
Fred Bloggs vomited:
John Larkin wrote:
snip
We all have points of view here. I'm not certain that one can
say that any one's person's view is any more legitimate than an |
other's. In the end, it all comes down to evidence or in some
cases the lack of it !
Strange statement. Fred never has anything constructive to say to
me, or about me if he can fine someone to reply, since I never see
his postings!
Do you not see the difference between constructive comment and
deliberate nonsense? Remember that Fred Bloggs has nothing at
stake! I am the only one doing the design work on the electronics
of a critical piece of aircraft safety equipment. The design I
was told to "Modify, is ON aircraft now! Scares me, and I wasn't
the one who did the deed!
| Quote: | Anyway, I'm sure that you must appreciate the joy I felt when
that idea came into my head. |
I am sure that the feeling was accompanied by the realization that
it meant you were still alive? Congratulations, that is certainly
something to celebrate.
Have a good day. |
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Clarence_A
Guest
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| Posted:
Mon Feb 07, 2005 5:03 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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"Jim Thompson" <thegreatone@example.com> wrote in message
news:v2vc015qc3folg1lgrfbhqu203nc3roi71@4ax.com...
| Quote: | On Sun, 06 Feb 2005 20:17:48 GMT, fuclarence
xyz@xyz123456789.com
wrote:
[snip]
Why don't you plonk this and run- you little tutu wearing
flake...
Sheeesh! What have we come to? Even Fred has to resort to an
alias
to get read.
FuFred ;-)
...Jim Thompson
|
Gee, was that Freddy?
It did look like him! Or it rather sounded like him. He hasn't
changed at all.
I will be talking to the AD Engineer responsible for the product
on Monday to advise him and find if there is another explanation
for the problem. He wasn't in on Friday.
I do not work in a vacuum, and communicate with the responsible
parties at all venders I use.
By the way, many of the product people know me.
We have a beer at the various shows.
(I know, Wine would be better.) |
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Fred Bloggs
Guest
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| Posted:
Mon Feb 07, 2005 5:05 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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John Larkin wrote:
| Quote: |
Right now, I'm writing the self-test code for the B-52 bomber radar
thing, which is a real drag. So, tell us about something cool you're
working on now and make us jealous.
|
Ehhh- big deal- that is a relatively small job...not to mention the
work statement has been reduced to the primitive level...yawn. |
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Fred Bloggs
Guest
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| Posted:
Mon Feb 07, 2005 5:13 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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Clarence_A wrote:
| Quote: | "richard mullens" <mullensdeletethis@ntlworld.com> wrote in
Do you not see the difference between constructive comment and
deliberate nonsense? Remember that Fred Bloggs has nothing at
stake!
|
I will not waste bandwidth posting a copy of all your moronic garbage
posts- a very sick and irrational non-entity you are.
| Quote: | I am the only one doing the design work on the electronics
of a critical piece of aircraft safety equipment.
|
You are not doing "design work"- you are a F_Up, and damned joke.
| Quote: | The design I
was told to "Modify, is ON aircraft now! Scares me, and I wasn't
the one who did the deed!
|
Well- good that you found a reason for life- too bad it is all a joke
firedrill- but be sure to raise a big storm over it so the hapless
idiots who hired you can find out you are a moron -too.
GFOAD |
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Jim Thompson
Guest
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| Posted:
Mon Feb 07, 2005 5:18 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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On Sun, 06 Feb 2005 23:03:29 GMT, "Clarence_A" <no@No.com> wrote:
| Quote: |
"Jim Thompson" <thegreatone@example.com> wrote in message
news:v2vc015qc3folg1lgrfbhqu203nc3roi71@4ax.com...
On Sun, 06 Feb 2005 20:17:48 GMT, fuclarence
xyz@xyz123456789.com
wrote:
[snip]
Why don't you plonk this and run- you little tutu wearing
flake...
Sheeesh! What have we come to? Even Fred has to resort to an
alias
to get read.
FuFred ;-)
...Jim Thompson
Gee, was that Freddy?
It did look like him! Or it rather sounded like him. He hasn't
changed at all.
I will be talking to the AD Engineer responsible for the product
on Monday to advise him and find if there is another explanation
for the problem. He wasn't in on Friday.
I do not work in a vacuum, and communicate with the responsible
parties at all venders I use.
By the way, many of the product people know me.
We have a beer at the various shows.
(I know, Wine would be better.)
|
One thing I failed to mention... you might want to AC-gain-up your
signal before rectification... gets you out of offset problems, and
can allow cheaper OpAmps.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
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Fred Bloggs
Guest
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| Posted:
Mon Feb 07, 2005 5:24 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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Clarence_A wrote:
| Quote: |
I will be talking to the AD Engineer responsible for the product
on Monday to advise him and find if there is another explanation
for the problem. He wasn't in on Friday.
|
What a F_CKING moron and pest!- I am so sure they look forward to
fielding queries from you- with your ignorance, broken English, and
overall moronic demeanor and mindset.
| Quote: | I do not work in a vacuum, and communicate with the responsible
parties at all venders I use.
|
Oh my goodness- what a chatterbox you are!
| Quote: |
By the way, many of the product people know me.
We have a beer at the various shows.
(I know, Wine would be better.)
|
Know to avoid you, is what you mean.... |
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Clarence_A
Guest
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| Posted:
Mon Feb 07, 2005 6:25 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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"Jim Thompson" <thegreatone@example.com> wrote in message
news:4b9d015hudsupbsb9fa7hcmvp731km0e22@4ax.com...
| Quote: | On Sun, 06 Feb 2005 23:03:29 GMT, "Clarence_A" <no@No.com
wrote:
"Jim Thompson" <thegreatone@example.com> wrote in message
news:v2vc015qc3folg1lgrfbhqu203nc3roi71@4ax.com...
|
[snip]
| Quote: |
One thing I failed to mention... you might want to AC-gain-up
your
signal before rectification... gets you out of offset problems,
and
can allow cheaper OpAmps.
...Jim Thompson
|
The customer seems to want to know if the unit will work over a
very wide range. My nominal input (threshold) is 134 mV so I was
considering a gain of about 4 up front. They are not likely to
need the maximum of .6VRMS since that is more current than the
wiring will safely support.
This is another item on the list to discuss with the customer.
When I signed on to this project they'd already had a preliminary
design review, now they say they have to get permission to make
significant changes. I thought that until the 'critical design
review' the project was a work in progress.
I will start to build a first article in the coming week. (Brass
Board.)
I would prefer a different amp, for no other reason than I am more
familiar with its performance. However Cost is not an issue.
This unit sells for an increasable mark-up!
The good news is that they know they need this review and trust me
to get the unit to qualification test, since I have done many of
this type of project. |
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richard mullens
Guest
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| Posted:
Mon Feb 07, 2005 7:31 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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Clarence_A wrote:
| Quote: | "richard mullens" <mullensdeletethis@ntlworld.com> wrote in
message news:pcuNd.2782$KE2.39@newsfe3-win.ntli.net...
Clarence_A wrote:
"richard mullens" wrote
Fred Bloggs wrote:
John Larkin wrote:
snip
We all have points of view here. I'm not certain that one can say that any one's person's view is any more legitimate than an other's. In the end, it all comes down to evidence or in some cases the lack of it !
Strange statement. Fred never has anything constructive to say to me, or about me if he can fine someone to reply, since I never see his postings!
Do you not see the difference between constructive comment and deliberate nonsense? Remember that Fred Bloggs has nothing at stake! I am the only one doing the design work on the electronics of a critical piece of aircraft safety equipment. The design I was told to "Modify, is ON aircraft now! Scares me, and I wasn't the one who did the deed!
|
All I can say is that you must have done/said something to upset him. Because he is not like this with everyone. I recollect
that you wrote in reply to a message I posted "<snipped stupid remarks>". Perhaps you did something like that to him too? If
you call people stupid, sometimes they will take offence and return the favour.
It is best to respect other people's points of view - you do not necessarily have to hold them too. Remember that they may hold
them just as sincerely as you. |
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John Woodgate
Guest
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| Posted:
Mon Feb 07, 2005 8:41 am Post subject:
Re: Lookinf for options for an Absolute Magnitude" or precis |
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I read in sci.electronics.design that richard mullens <mullensdeletethis
@ntlworld.com> wrote (in <dyzNd.4671$Cq.649@newsfe1-win.ntli.net>) about
'Lookinf for options for an Absolute Magnitude" or precision rectifier
circuit.', on Mon, 7 Feb 2005:
| Quote: | All I can say is that you must have done/said something to upset him.
|
It takes very little to do that. Practically nothing.
| Quote: | Because he is not like this with everyone.
|
He is with nearly everyone. Your turn will come.
But he does put out very good designs, and very quickly, too.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk |
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