Re: [time-nuts] State of the art of crystal oscillator measurements
Good morning,
the difference between the two phase noise FWSP systems is the lower noise
internal 10 MHz reference crystal oscillator (optimized ) as well as
also some of the internal FSWP circuits custom optimized . The output power
was 17 dBm, but we also have build one oscillator with 12 dBm output power
and noise similar values.
This is part of a PhD project which I supervise . For values so close to
the carrier you need a very low noise power supply and a well shielded
Faraday cage . The measurement with ca 100 correlation took about 2 hours.
Also the heating circuit needs to be low noise and well decoupled .
The 100 Hz value of the better analyzer seems suspicious , It needs to be
further investigated.
All very exciting and time consuming .
Ulrich
In a message dated 8/10/2016 11:02:25 P.M. Eastern Daylight Time,
mfeher@eozinc.com writes:
These seem extremely fantastic results for a 100 MHz oscillator. I am
curious what the Po of the oscillators are Regards - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Tom Van
Baak
Sent: Wednesday, August 10, 2016 9:19 PM
To: Discussion of precise time and frequency measurement
Cc: enrico.rubiola@gmail.com
Subject: Re: [time-nuts] State of the art of crystal oscillator
measurements
Attached is a GIF of the table Ulrich wants to share.
Note time-nuts is a plain text mailing list so any rtf or html formatting
is discarded.
On the bright side, PDF or data or image attachments are allowed with no
problem.
/tvb
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.
Ulrich -
This may be a naive question, but, how can you achieve results that are so
close to, and sometimes at further out are below kT? Thanks & 73 - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
From: KA2WEU@aol.com [mailto:KA2WEU@aol.com]
Sent: Thursday, August 11, 2016 7:03 AM
To: time-nuts@febo.com; tvb@leapsecond.com
Cc: enrico.rubiola@gmail.com; mfeher@eozinc.com
Subject: Re: [time-nuts] State of the art of crystal oscillator measurements
Good morning,
the difference between the two phase noise FWSP systems is the lower noise
internal 10 MHz reference crystal oscillator (optimized ) as well as also
some of the internal FSWP circuits custom optimized . The output power was
17 dBm, but we also have build one oscillator with 12 dBm output power and
noise similar values.
This is part of a PhD project which I supervise . For values so close to
the carrier you need a very low noise power supply and a well shielded
Faraday cage . The measurement with ca 100 correlation took about 2 hours.
Also the heating circuit needs to be low noise and well decoupled .
The 100 Hz value of the better analyzer seems suspicious , It needs to be
further investigated.
All very exciting and time consuming .
Ulrich
In a message dated 8/10/2016 11:02:25 P.M. Eastern Daylight Time,
mfeher@eozinc.com writes:
These seem extremely fantastic results for a 100 MHz oscillator. I am
curious what the Po of the oscillators are Regards - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Tom Van
Baak
Sent: Wednesday, August 10, 2016 9:19 PM
To: Discussion of precise time and frequency measurement
Cc: enrico.rubiola@gmail.com
Subject: Re: [time-nuts] State of the art of crystal oscillator measurements
Attached is a GIF of the table Ulrich wants to share.
Note time-nuts is a plain text mailing list so any rtf or html formatting is
discarded.
On the bright side, PDF or data or image attachments are allowed with no
problem.
/tvb
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.
Ulrich -
This may be a naive question, but, how can you achieve results that are so
close to, and sometimes at further out are below kT? Thanks & 73 - Mike
Mike B. Feher, EOZ Inc.
---==========
.. by reducing T?
David
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor@blueyonder.co.uk
Twitter: @gm8arv
On 8/11/2016 5:01 AM, Mike Feher wrote:
This may be a naive question, but, how can you achieve results that are so
close to, and sometimes at further out are below kT? Thanks & 73 - Mike
Mike B. Feher, EOZ Inc.
kT per see is not the relevant parameter. It is the
ratio between kT and signal level that determines the
limit on phase noise. Also, when you extract an
oscillator signal through the resonator, then at offsets
from the carrier, the resonator filters out noise and
the output noise can be way below kT. Ulrich first
published on this in 1977. Earliest reference I know of.
I actually remember reading it in 1977.
The old HP608 signal generator routinely produced far
out phase noise floor well below kT. AFAIK, for this
particular spec, it better than any other signal generator
ever built. What's the secret? It has a tracking
POST-selector filter that follows the oscillator when
you turn the mechanical tuning knob. There is a little
tracking adjustment knob to peak it. Not really magic.
Rick
kT is indeed relevant for a physical implementation. - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Richard (Rick) Karlquist
Sent: Thursday, August 11, 2016 1:40 PM
To: Discussion of precise time and frequency measurement; KA2WEU@aol.com; tvb@leapsecond.com
Cc: enrico.rubiola@gmail.com
Subject: Re: [time-nuts] State of the art of crystal oscillator measurements
On 8/11/2016 5:01 AM, Mike Feher wrote:
This may be a naive question, but, how can you achieve results that
are so close to, and sometimes at further out are below kT? Thanks &
73 - Mike
Mike B. Feher, EOZ Inc.
kT per see is not the relevant parameter. It is the ratio between kT and signal level that determines the limit on phase noise. Also, when you extract an oscillator signal through the resonator, then at offsets from the carrier, the resonator filters out noise and the output noise can be way below kT. Ulrich first published on this in 1977. Earliest reference I know of.
I actually remember reading it in 1977.
The old HP608 signal generator routinely produced far out phase noise floor well below kT. AFAIK, for this particular spec, it better than any other signal generator ever built. What's the secret? It has a tracking POST-selector filter that follows the oscillator when you turn the mechanical tuning knob. There is a little tracking adjustment knob to peak it. Not really magic.
Rick
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.
Remember that L(f) is expressed in dBc/Hz, not dBm/Hz. If it were dBm/Hz, then kT would be the limit. But in dBc/Hz terms, the limit is 177 + the DUT's output power in dBm.
Assuming a 50 ohm system, of course.
-- john, KE5FX
Miles Design LLC
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Mike
Feher
Sent: Thursday, August 11, 2016 12:51 PM
To: 'Discussion of precise time and frequency measurement';
KA2WEU@aol.com; tvb@leapsecond.com
Cc: enrico.rubiola@gmail.com
Subject: Re: [time-nuts] State of the art of crystal oscillator measurements
kT is indeed relevant for a physical implementation. - Mike
Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-902-3831 cell
Or rather -(177+DUT output power in dBm). The minus sign makes the difference between the thermal floor and a nuclear war!
-- john, KE5FX
Miles Design LLC
Remember that L(f) is expressed in dBc/Hz, not dBm/Hz. If it were dBm/Hz,
then kT would be the limit. But in dBc/Hz terms, the limit is 177 + the DUT's
output power in dBm.
Hi
The gotcha is that you don’t have to have a 50 ohm system. An output stage with
a narrow band tuned tank is one example of a very “not 50 ohms” system.
There is also a whole debate around the “is 50 ohm source into 50 ohm load really 25 ohms”.
That will give you a 3 db delta to bet beers about. The 3 db split of thermal noise between AM
noise and PM noise is fairly well accepted, but it still can be challenged.
So is the floor -174 - 3 = -177 or is it something else ….
If we have a -195.4 dbc/ Hz oscillator that puts out < 18 dbm in a 50 ohm system it’s not -177 or
it’s not a 50 ohm system.
Bob
On Aug 11, 2016, at 4:47 PM, John Miles john@miles.io wrote:
Or rather -(177+DUT output power in dBm). The minus sign makes the difference between the thermal floor and a nuclear war!
-- john, KE5FX
Miles Design LLC
Remember that L(f) is expressed in dBc/Hz, not dBm/Hz. If it were dBm/Hz,
then kT would be the limit. But in dBc/Hz terms, the limit is 177 + the DUT's
output power in dBm.
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.
Zo doesn't matter for these purposes.
dBm works just as well for 75 ohm systems.
On 8/11/2016 1:22 PM, John Miles wrote:
Remember that L(f) is expressed in dBc/Hz, not dBm/Hz. If it were dBm/Hz, then kT would be the limit. But in dBc/Hz terms, the limit is 177 + the DUT's output power in dBm.
Assuming a 50 ohm system, of course.
-- john, KE5FX
Miles Design LLC
Good point, the 'milliwatt' part of 'dBm' takes the E^2/R part out of the math. If we were speaking of dBv/Hz, the system Zo would need to be considered to determine the power.
-- john, KE5FX
Miles Design LLC
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Richard
(Rick) Karlquist
Sent: Thursday, August 11, 2016 3:01 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] State of the art of crystal oscillator measurements
Zo doesn't matter for these purposes.
dBm works just as well for 75 ohm systems.