[time-nuts] AM vs PM noise of signal sources

Dr. Ulrich L. Rohde ka2weu at aol.com
Sun Jan 7 12:10:45 EST 2018


You are simply correct !

Ulrich 

Sent from my iPhone

> On Jan 7, 2018, at 11:05 AM, Arnold Tibus <arnold.tibus at gmx.de> wrote:
> 
>> Am 07.01.2018 um 16:33 schrieb jimlux:
>>> On 1/6/18 6:12 PM, Dana Whitlow wrote:
>>> One point about oscillator design I've not yet seen mentioned is this: the
>>> limiter
>>> must not degrade the resonator Q when in action.  Hence, a pair of diodes
>>> connected in parallel back to back, across a shunt resonator, would be a bad
>>> thing to do from the perspective of low phase noise. A differential
>>> amplifier
>>> that limits by running out of current on peaks, driving a shunt resonator,
>>> is
>>> a much better way even though one pays a price in having more transistor
>>> noise in the circuit.
>>> 
>>> I've long wondered if a very slow AGC might avoid the nonlinear mechanisms
>>> issue except, of course, for things happening within the AGC loop's
>>> bandwidth.
>>> 
>> That's the Wein bridge stabilized by a light bulb, popularized by Messrs Hewlett and Packard a while ago.
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> 
> 
> Hello everybody, excuse me please,
> 
> but I see quite often mentioned the 'Wein bridge'. (Wein in german is 'vino' or 'wine' ;-)
> Not of real technical importance, but shouldn't this not be correctly called a 'Wien bridge'?
> As I know that this tricky circuit was developed by Max Wien in 1891.
> Max Karl Werner Wien was a German physicist and the director of the Institute of Physics at the University of Jena at that time.
> (sorry, I am a nut ;-)  )
> 
> My best wishes for 2018 to everybody,
> 
> Arnold, DK2WT
> 
> 
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