[time-nuts] Low noise power supplies for time nuts circuitry

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Nov 22 13:17:18 EST 2011


Another potential problem is that the cascaded emitter follower circuit 
shown is likely to oscillate in the VHF region.
An unbypassed resistor in series with the base of each emitter follower 
should be used.

Bruce
Bruce Griffiths wrote:
> Omitting the output bypass cap in the single transistor Wenzel 
> cancellation circuit is somewhat misleading in that it reduces the 
> high frequency attenuation,
> All his other circuits include such caps.
> A simple tweak (adjusting a resistor ratio) which makes the shunt 
> transistor collector current approximately PTAT significantly reduces 
> the temperature dependence of the cancellation.
>
> Bruce
>
> Bob Camp wrote:
>> Hi
>>
>> Interesting site - Thanks!
>>
>> A couple of observations:
>>
>> There are a couple of circuits (low noise op-amp based) that can 
>> generate lower noise than what he's shown.
>>
>> You need to be careful looking at his results. A lot of what he shows 
>> is the result of changing the model used for the output capacitor….
>>
>> Still well worth looking at.
>>
>> Bob
>>
>>
>> On Nov 22, 2011, at 7:07 AM, Ulrich Bangert wrote:
>>
>>> Gentlemen,
>>>
>>> i would like to draw your attention to this site:
>>>
>>> http://pstca.com/spice/ripple/ripple.htm
>>>
>>> The author of this site thank-worthy not only presents circuits for 
>>> power supply finesse but also simulates them with SPICE. It seems to 
>>> turn out as if the well known Wenzel suggestions for voltage 
>>> regulator finesse were not state of the art and other circuits 
>>> (although similar in principle) may easily outperform them.
>>>
>>> Best regards
>>>
>>> Ulrich Bangert
>>> Ortholzer Weg1
>>> 27243 Gross Ippener
>>> Deutschland
>>> Tel   +49 (0)4224 95071
>>> Fax  +49 (0)4224 95072
>>> Mob +49 (0)172 8006546
>>> www.ulrich-bangert.de
>>>
>>>
>>>





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