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Re: [time-nuts] State of the art of crystal oscillator measurements

K
KA2WEU@aol.com
Thu, Aug 11, 2016 11:10 PM
Values  of kT at 25°C (298 K) Units  kT = 4.11×10−21 _J_ 

(https://en.wikipedia.org/wiki/Joule)  kT = 4.114 pN⋅nm  kT = 9.83×10−22 cal
(https://en.wikipedia.org/wiki/Calorie)  kT = 25.7 meV
(https://en.wikipedia.org/wiki/Electron-volt)    Related quantities  kT/hc = 200 cm-1  kT/e = 25.7 mV
(https://en.wikipedia.org/wiki/Volt)  RT = kT ⋅ NA
(https://en.wikipedia.org/wiki/Avogadro's_number)  = 2.479 kJ⋅mol-1
(https://en.wikipedia.org/wiki/Joule_per_mole)  u = 0.593 kcal⋅mol−1
(https://en.wikipedia.org/wiki/Kilocalorie_per_moleh (https://en.wikipedia.org/wiki/Planck_constant)
/kT = 0.16 ps (https://en.wikipedia.org/wiki/Picosecond)

In a message dated 8/11/2016 7:02:13 P.M. Eastern Daylight Time,
john@miles.io writes:

Right,  I'm speaking specifically of L(f).  The device being driven by the
oscillator doesn't care about the NF of the driver stage, only what a PN
analyzer would measure at the output jack.

For any 50-ohm source, the  practical L(f) floor is -177 dBm/Hz - the
carrier power in dBm.  No  oscillator with an output of 0 dBm can be quieter than
-177 dBc/Hz at any  offset, but an oscillator that puts out +20 dBm could
approach -197  dBc/Hz.

Given a proverbial black box containing a +17 dBm oscillator  that measures
-195 dBc/Hz at 100 kHz, the interesting question is, "What's in  the box?"
There could be a passive resonator that's shaving off the  broadband noise
after the last active stage without contributing additive  noise of its own.
Another possibility might be cross-spectral collapse  due to correlated
thermal noise from the splitter.

--  john, KE5FX
Miles Design LLC

-----Original  Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On  Behalf Of KA2WEU--

  • via time-nuts
    Sent: Thursday, August 11,  2016 2:37 PM
    To: time-nuts@febo.com
    Subject: Re: [time-nuts]  State of the art of crystal oscillator

measurements

NO, the  maximum  possible noise dynamic range is ( 177 +  Pout)  [dBm]

Transistor large signal NF ( dB),
the  signal to noise ration is dimensionless !!!!


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Values of kT at 25°C (298 K) Units kT = 4.11×10−21 _J_ (https://en.wikipedia.org/wiki/Joule) kT = 4.114 pN⋅nm kT = 9.83×10−22 _cal_ (https://en.wikipedia.org/wiki/Calorie) kT = 25.7 _meV_ (https://en.wikipedia.org/wiki/Electron-volt) Related quantities kT/hc = 200 cm-1 kT/e = 25.7 _mV_ (https://en.wikipedia.org/wiki/Volt) RT = kT ⋅ _NA_ (https://en.wikipedia.org/wiki/Avogadro's_number) = 2.479 _kJ⋅mol-1_ (https://en.wikipedia.org/wiki/Joule_per_mole) u = 0.593 _kcal⋅mol−1_ (https://en.wikipedia.org/wiki/Kilocalorie_per_mole) _h_ (https://en.wikipedia.org/wiki/Planck_constant) /kT = 0.16 _ps_ (https://en.wikipedia.org/wiki/Picosecond) In a message dated 8/11/2016 7:02:13 P.M. Eastern Daylight Time, john@miles.io writes: Right, I'm speaking specifically of L(f). The device being driven by the oscillator doesn't care about the NF of the driver stage, only what a PN analyzer would measure at the output jack. For any 50-ohm source, the practical L(f) floor is -177 dBm/Hz - the carrier power in dBm. No oscillator with an output of 0 dBm can be quieter than -177 dBc/Hz at any offset, but an oscillator that puts out +20 dBm could approach -197 dBc/Hz. Given a proverbial black box containing a +17 dBm oscillator that measures -195 dBc/Hz at 100 kHz, the interesting question is, "What's in the box?" There could be a passive resonator that's shaving off the broadband noise after the last active stage without contributing additive noise of its own. Another possibility might be cross-spectral collapse due to correlated thermal noise from the splitter. -- john, KE5FX Miles Design LLC > -----Original Message----- > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of KA2WEU-- > - via time-nuts > Sent: Thursday, August 11, 2016 2:37 PM > To: time-nuts@febo.com > Subject: Re: [time-nuts] State of the art of crystal oscillator measurements > > NO, the maximum possible noise dynamic range is ( 177 + Pout) [dBm] - > Transistor large signal NF ( dB), > the signal to noise ration is dimensionless !!!! > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.