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Old 14th March 2011, 03:43 AM   #1
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Default how much achievable gain with UGS?

Hi,

I am curious: is it possible to achieve up to 60dB gain with a UGS voltage gain stage?
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Old 14th March 2011, 01:11 PM   #2
amhlee is offline amhlee  Hong Kong
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I do not think so..... I have tried 5x which is the same on the X2
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Old 15th March 2011, 04:35 AM   #3
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As I recall, a stock UGS does not have an open loop figure
anywhere near that high. You can modify it for that tho,
(he asked, wondering why you would want that)

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Old 16th March 2011, 02:59 AM   #4
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Quote:
Originally Posted by Nelson Pass View Post
As I recall, a stock UGS does not have an open loop figure
anywhere near that high. You can modify it for that tho,
(he asked, wondering why you would want that)

yeah I made the calculation and OL is not more than 17-20dB.
Eventually more gain could be achieved by adding a second buffer stage and closing the loop with that, although it would be nice to have very linear jfets, as good as Jk74/170, but with very high transconductance to be able to achieve that sort of gain with just one stage .

In this fashion anyways OL will go high enough to achieve 40-50dB gain.

Nelson I have a question though regarding phase response:

I am sure you have the possibility to make frequeny and phase response of your gears.
What do you consider a good phase response?
I know there is correlation with phase delay and fidelity on the reproduction and phase vs. OL/CLG i.e. FB gain as well.

Should the phase be as linear as possible? Should it be as close to 0 as possible?
I know the latter is the ideal although pretty impossible

Should I look at log(phase) or linear scale across let's say 10Hz 10MHz?

I am taking measuraments with the Vector analyzer HP4395A and using the Tek scope MSO9000 the 1Ghz mixed signal scope.

I am interested to know what you think about phase response.
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Old 28th January 2013, 11:56 AM   #5
AndrewT is offline AndrewT  Scotland
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He never got any answers.
Can anyone help explain what he (and us) is after?
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Old 28th January 2013, 12:01 PM   #6
The Dastardly Dad of Three
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What's a UGS? Some kind of boots ? (Lik
e the kind im gonna get up my ** for asking ?)
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