[time-nuts] Lady Heather on MacOS X

[Mark Sims]

I have the next release of Lady Heather working on macOS / OSX.  Seems to work 
quite well.  The makefile auto-detects Linux or macOS... (stupid Windoze make 
does not support conditionals so it needs its own makefile).  macOS does use 
XQuartz for the X11 video/mouse/keyboard stuff.  XQuartz does have a couple of 
quirks... mainly you can't restore the previous window size if you maximize the 
window then try to restore it.

I just got through cleaning up the OS support code and decoupled the operating 
system relevant code (#ifdef WINDOWS,  #ifdef __linux__, and #ifdef __MACH__) 
code from the video/mouse/keyboard code (#ifdef WIN_VFX and #ifdef USE_X11).  
Also made the drawing routines much less display system dependent.  This should 
make it easier to port to other systems and display managers.  Windows, Linux, 
and Mac should cover 99.9% of users.   I suspect BSD support would be trivial 
since mscOS is based on BSD (and Heather only has a couple dozen lines of code 
specific to macOS).

I also deleted all the old DOS support code.  Heather had gotten way to beefy 
for that to ever work again.

The next release should be out in a couple of weeks... I'm waiting for a Lucent 
KS system to come in and verify it works with that,
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[time-nuts] FS: PICTIC II

[Joseph Gray]

More house cleaning.

I have two PCB and all the parts (from Mouser) to build two PICTIC II
units. Make me an offer.

Joe Gray
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[time-nuts] Lady Heather on MacOS X

[Nick Sayer via time-nuts]

Sorry if this is old hat, but I don’t remember seeing it go by.

I just went through the exercise of getting Lady Heather working on MacOS X.

It’s not a Quartz port - you have to install and run XQuartz for it to work.

One patch to heather.ch was needed:

Right below the include of fcntl.h:

#ifndef SOCK_NONBLOCK
#define SOCK_NONBLOCK O_NONBLOCK
#endif

And then this Makefile:

CFLAGS+= -I/opt/X11/include -D__linux__ -Wno-write-strings
LFLAGS+= -L/opt/X11/lib 

all: heather

heather.o: heather.cpp heather.ch heathfnt.ch makefile
g++ $(CFLAGS) -c heather.cpp

heathmsc.o: heathmsc.cpp heather.ch heathfnt.ch makefile
g++ $(CFLAGS) -c heathmsc.cpp

heathui.o: heathui.cpp heather.ch heathfnt.ch makefile
g++ $(CFLAGS) -c heathui.cpp

heathgps.o: heathgps.cpp heather.ch heathfnt.ch makefile
g++ $(CFLAGS) -c heathgps.cpp

heather: heather.o heathmsc.o heathui.o heathgps.o
g++ $(LFLAGS) heather.o heathui.o heathgps.o heathmsc.o -o heather -lm 
-lX11

clean:
rm heather.o heathui.o heathgps.o heathmsc.o heather


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[time-nuts] Ig Nobel ceremonies & time

[Eric Scace]

I had the happy fortune to attend this year’s Ig Nobel award ceremonies, the 
agenda of which is found here . This was 
the 26th First Annual Ig Novel Prize Ceremony

This year’s program featured “time”, including:
a mini-opera “The Last Second”, whose plot involves a leap second that goes 
very wrong.
micro-lectures by:
Prof Jenny Hoffman, Harvard physics: “What is a Leap Second, and Why Do We 
Create Them?”
John Lowe (NIST, Boulder): “How Scientists Decide When to Create a Leap Second, 
and How We Do It”
Eric Maskin, Nobel laureate, economics: “The Kinds of Financial Mischief That 
Could Be Done During an Unannounced Extra Leap Second”
Each time the word “time” was mentioned, the cheerleading section of the 
audience groaned.

All the micro-lectures were excellent — and John Lowe especially so. You can 
listen to it, the opera, and all the rest of the ceremony, on the upcoming Nov 
25 “Science Friday” program on public radio. Broadcast times here 
. Or, if impatient, the entire ceremony is 
available on YouTube  now.

I now return you back to our usual programming… 

— Eric
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Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

If you do a power sweep on a crystal resonance, it’s a very predictable sort of 
thing.
Essentially you “chase” the resonance up (or down) in frequency with the sweep. 
At some
point, it “snaps” and drops back to the low power line. I suspect that what is 
being observed 
is the “snap” as the crystal stops accepting power.

In some crystals, you can get a very observable effect at a few hundred 
microwatts. With 
other designs it’s 10’s of microwaves or maybe even up around a milliwatt. 

Liquid nitrogen cooled crystals anyone? :) 

Bob

> On Oct 2, 2016, at 4:49 PM, Chuck Harris  wrote:
> 
> That is a most interesting suggestion.
> 
> Suppose the filter crystal was pulled to the DUT frequency, and due
> to the inertia of its very high Q, was able to show you the phase noise
> variations of the DUT better than one might expect?
> 
> -Chuck Harris
> 
> 
> Bob Camp wrote:
>> .One thing you may be seeing is the crystal shift frequency as it is 
>> tuned to “accept” power from the source. 
>> With milliwatts of power flying around, that would not be unusual. 
> 
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Re: [time-nuts] notch filter for close in phase noise measurement

[Chuck Harris]

That is a most interesting suggestion.

Suppose the filter crystal was pulled to the DUT frequency, and due
to the inertia of its very high Q, was able to show you the phase noise
variations of the DUT better than one might expect?

-Chuck Harris


Bob Camp wrote:
>.One thing you may be seeing is the crystal shift frequency as it is tuned 
>to “accept” power from the source. 
> With milliwatts of power flying around, that would not be unusual. 

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Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

If you need the notch to be set within 0.1 Hz at 10 MHz, that’s 1x10^-8. A 
typical crystal will have a temperature
coefficient of about 0.5 ppm / C. You would need to temperature control it to < 
1/50 C. A normal lab will swing between
1 and 2 C. One thing you may be seeing is the crystal shift frequency as it is 
tuned to “accept” power from the source. 
With milliwatts of power flying around, that would not be unusual. 

The same calculation sort of (but not really) gets you headed to a loaded Q in 
the 100,000,000 range. That’s a bit
optimistic for a fundamental AT crystal at 10 MHz. 300,000 for the unloaded Q 
is a fairly normal upper limit. The loaded
Q in the circuit will always be well below the unloaded Q.  Not all crystals 
are designed to optimize Q. You really don’t know
what you have without measurement of the crystal. 

Yes, we are going from “remembered numbers” and that is always a bit dangerous. 
I’ve certainly had *my*
issues with that here on the list. :)

Bob


> On Oct 2, 2016, at 3:14 PM, Adrian Rus  wrote:
> 
> You throw away the 50dB figure, not me :)
> I will revert with numbers as I have to redo the settings. The bandwidth is 
> much, much lower than 30Hz. From memory, the -58dB notch is valid for 0.1Hz 
> freq shift only.
> Adrian
> 
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 22:09
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
> 
> 
> Hi
> 
> One of the limitations of the return loss bridge approach can be the loaded 
> Q. Indeed 50 db
> would be pretty awful.  You have more control over things like notch depth 
> and bandwidth with
> a more “classical” notch filter topology. You can indeed use overtone 
> crystals in that case
> which gives you a higher unloaded Q from the resonator.
> 
> If indeed you come up with a 30 Hz wide at 3 db notch filter, you better put 
> it in an OCXO style
> enclosure. You also better have a way to tune it to match your signal source. 
> Room ambient
> variations will have you chasing it all over the place otherwise. Even a 200 
> Hz wide filter is going
> to be “twitchy” if that is the 3 db bandwidth.
> 
> Bob
> 
>> On Oct 2, 2016, at 12:27 PM, Scott Stobbe  wrote:
>> 
>> What's the loaded Q of such a notch filter? 50 dB 100 Hz off of 10 MHz
>> sounds like a pretty lousy Q.
>> 
>> On Sunday, 2 October 2016, Bob Camp  wrote:
>> 
>>> Hi
>>> 
>>> The issue is *not* about notch filters and if they are useful. The gotcha
>>> is
>>> that they are mainly useful far removed from carrier rather than close in.
>>> The
>>> statement “works 100 Hz off carrier” requires a *lot* of qualifiers to
>>> make it
>>> apply in real measurements.  Without getting into the limitations, it is
>>> very difficult
>>> to determine just how close to carrier you can go with a notch. That is not
>>> implementation specific it applies to all notches. You *do* need to get
>>> into the
>>> details.
>>> 
>>> The stuff we have gone over so far is hardly an exhaustive list. There are
>>> many issues.
>>> We have yet to get into the amount of power being delivered to the crystal
>>> in the
>>> notch filter and the behavior of crystals when driven with a lot of power
>>> ….
>>> 
>>> Bob
>>> 
 On Oct 2, 2016, at 12:10 PM, Adrian Rus >> > wrote:
 
 Bob,
 There is no issue about using or not using notch filters. We know (?)
>>> all of these. It is about a damn simple topology. Yes, this topology has
>>> its shortcomings (impedance, variation with freq and the so).
 The math is close, but not exact.
 I gave up here. If the topology is of no use, this is it. For me it was
>>> funy to _discover_ that simple topology doing a notch.
 ‎Best,
 Adrian
 
 Sent from my BlackBerry 10 smartphone on the Orange network.
 Original Message
 From: Bob Camp
 Sent: Sunday, October 2, 2016 18:35
 To: Discussion of precise time and frequency measurement
 Reply To: Discussion of precise time and frequency measurement
 Subject: Re: [time-nuts] notch filter for close in phase noise
>>> measurement
 
 
 Hi
 
 Ok, the next issue with the notch filter technique is the termination of
>>> the oscillator
 it’s self. The notch may (or more likely not) provide a proper 50 ohm
>>> load at the
 carrier frequency. Even if it is correct at the carrier, it will go off
>>> impedance as it
 moves away from carrier.  You either need a pad in series with the
>>> oscillator (which
 drops sensitivity) or something similar (like an isolator). The gotcha
>>> here is that the
 phase noise of the device may not be the same when it is incorrectly
>>> terminated. The
 issue is more significant in minimum stage devices or when the output
>>> stage contributes
 to the total noise of t

Re: [time-nuts] Schematic needed

[Joseph Gray]

Thanks to two list members, I got what I needed.

Joe Gray
W5JG
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Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

You throw away the 50dB figure, not me :)
I will revert with numbers as I have to redo the settings. The bandwidth is 
much, much lower than 30Hz. From memory, the -58dB notch is valid for 0.1Hz 
freq shift only.
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Bob Camp
Sent: Sunday, October 2, 2016 22:09
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


Hi

One of the limitations of the return loss bridge approach can be the loaded Q. 
Indeed 50 db
would be pretty awful.  You have more control over things like notch depth and 
bandwidth with
a more “classical” notch filter topology. You can indeed use overtone crystals 
in that case
which gives you a higher unloaded Q from the resonator.

If indeed you come up with a 30 Hz wide at 3 db notch filter, you better put it 
in an OCXO style
enclosure. You also better have a way to tune it to match your signal source. 
Room ambient
variations will have you chasing it all over the place otherwise. Even a 200 Hz 
wide filter is going
to be “twitchy” if that is the 3 db bandwidth.

Bob

> On Oct 2, 2016, at 12:27 PM, Scott Stobbe  wrote:
>
> What's the loaded Q of such a notch filter? 50 dB 100 Hz off of 10 MHz
> sounds like a pretty lousy Q.
>
> On Sunday, 2 October 2016, Bob Camp  wrote:
>
>> Hi
>>
>> The issue is *not* about notch filters and if they are useful. The gotcha
>> is
>> that they are mainly useful far removed from carrier rather than close in.
>> The
>> statement “works 100 Hz off carrier” requires a *lot* of qualifiers to
>> make it
>> apply in real measurements.  Without getting into the limitations, it is
>> very difficult
>> to determine just how close to carrier you can go with a notch. That is not
>> implementation specific it applies to all notches. You *do* need to get
>> into the
>> details.
>>
>> The stuff we have gone over so far is hardly an exhaustive list. There are
>> many issues.
>> We have yet to get into the amount of power being delivered to the crystal
>> in the
>> notch filter and the behavior of crystals when driven with a lot of power
>> ….
>>
>> Bob
>>
>>> On Oct 2, 2016, at 12:10 PM, Adrian Rus > > wrote:
>>>
>>> Bob,
>>> There is no issue about using or not using notch filters. We know (?)
>> all of these. It is about a damn simple topology. Yes, this topology has
>> its shortcomings (impedance, variation with freq and the so).
>>> The math is close, but not exact.
>>> I gave up here. If the topology is of no use, this is it. For me it was
>> funy to _discover_ that simple topology doing a notch.
>>> ‎Best,
>>> Adrian
>>>
>>> Sent from my BlackBerry 10 smartphone on the Orange network.
>>> Original Message
>>> From: Bob Camp
>>> Sent: Sunday, October 2, 2016 18:35
>>> To: Discussion of precise time and frequency measurement
>>> Reply To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] notch filter for close in phase noise
>> measurement
>>>
>>>
>>> Hi
>>>
>>> Ok, the next issue with the notch filter technique is the termination of
>> the oscillator
>>> it’s self. The notch may (or more likely not) provide a proper 50 ohm
>> load at the
>>> carrier frequency. Even if it is correct at the carrier, it will go off
>> impedance as it
>>> moves away from carrier.  You either need a pad in series with the
>> oscillator (which
>>> drops sensitivity) or something similar (like an isolator). The gotcha
>> here is that the
>>> phase noise of the device may not be the same when it is incorrectly
>> terminated. The
>>> issue is more significant in minimum stage devices or when the output
>> stage contributes
>>> to the total noise of the device.
>>>
>>> A bit of math:
>>>
>>> A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at
>> 100 Hz off carrier.
>>> If you have lost 20 db of energy due to the notch width, that is now
>> -175 to -185 dbc / Hz.
>>> If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm
>> / Hz. The lower
>>> number is at the KTB level without any loss in the bridge, a the
>> attenuator, or noise figure in the
>>> post amplifier. The higher number is only 10 db away. If the notch has a
>> bit more loss, things
>>> get even tighter. This is more than just a theoretical issue.
>>>
>>> After that you do get into the AM + PM thing. The notch is normally
>> proposed for use on
>>> floor measurements. Details are in the FCS paper by Stone back in the
>> 1970’s.  There the argument
>>> is that the noise process *must* be producing equal amounts of AM and PM
>> noise. That makes
>>> the conversion of “what I measured” to phase noise fairly easy. Close
>> in, you can indeed have
>>> processes that produce unequal amounts of AM and PM noise. Without a way
>> to separate the
>>> two, you toss a fairly large bit of doubt into the measurement.
>>>
>>> Bob
>>>
>>>
 On Oct

Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

One of the limitations of the return loss bridge approach can be the loaded Q. 
Indeed 50 db
would be pretty awful.  You have more control over things like notch depth and 
bandwidth with
a more “classical” notch filter topology. You can indeed use overtone crystals 
in that case
which gives you a higher unloaded Q from the resonator. 

If indeed you come up with a 30 Hz wide at 3 db notch filter, you better put it 
in an OCXO style
enclosure. You also better have a way to tune it to match your signal source. 
Room ambient
variations will have you chasing it all over the place otherwise. Even a 200 Hz 
wide filter is going 
to be “twitchy” if that is the 3 db bandwidth. 

Bob

> On Oct 2, 2016, at 12:27 PM, Scott Stobbe  wrote:
> 
> What's the loaded Q of such a notch filter? 50 dB 100 Hz off of 10 MHz
> sounds like a pretty lousy Q.
> 
> On Sunday, 2 October 2016, Bob Camp  wrote:
> 
>> Hi
>> 
>> The issue is *not* about notch filters and if they are useful. The gotcha
>> is
>> that they are mainly useful far removed from carrier rather than close in.
>> The
>> statement “works 100 Hz off carrier” requires a *lot* of qualifiers to
>> make it
>> apply in real measurements.  Without getting into the limitations, it is
>> very difficult
>> to determine just how close to carrier you can go with a notch. That is not
>> implementation specific it applies to all notches. You *do* need to get
>> into the
>> details.
>> 
>> The stuff we have gone over so far is hardly an exhaustive list. There are
>> many issues.
>> We have yet to get into the amount of power being delivered to the crystal
>> in the
>> notch filter and the behavior of crystals when driven with a lot of power
>> ….
>> 
>> Bob
>> 
>>> On Oct 2, 2016, at 12:10 PM, Adrian Rus > > wrote:
>>> 
>>> Bob,
>>> There is no issue about using or not using notch filters. We know (?)
>> all of these. It is about a damn simple topology. Yes, this topology has
>> its shortcomings (impedance, variation with freq and the so).
>>> The math is close, but not exact.
>>> I gave up here. If the topology is of no use, this is it. For me it was
>> funy to _discover_ that simple topology doing a notch.
>>> ‎Best,
>>> Adrian
>>> 
>>> Sent from my BlackBerry 10 smartphone on the Orange network.
>>> Original Message
>>> From: Bob Camp
>>> Sent: Sunday, October 2, 2016 18:35
>>> To: Discussion of precise time and frequency measurement
>>> Reply To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] notch filter for close in phase noise
>> measurement
>>> 
>>> 
>>> Hi
>>> 
>>> Ok, the next issue with the notch filter technique is the termination of
>> the oscillator
>>> it’s self. The notch may (or more likely not) provide a proper 50 ohm
>> load at the
>>> carrier frequency. Even if it is correct at the carrier, it will go off
>> impedance as it
>>> moves away from carrier.  You either need a pad in series with the
>> oscillator (which
>>> drops sensitivity) or something similar (like an isolator). The gotcha
>> here is that the
>>> phase noise of the device may not be the same when it is incorrectly
>> terminated. The
>>> issue is more significant in minimum stage devices or when the output
>> stage contributes
>>> to the total noise of the device.
>>> 
>>> A bit of math:
>>> 
>>> A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at
>> 100 Hz off carrier.
>>> If you have lost 20 db of energy due to the notch width, that is now
>> -175 to -185 dbc / Hz.
>>> If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm
>> / Hz. The lower
>>> number is at the KTB level without any loss in the bridge, a the
>> attenuator, or noise figure in the
>>> post amplifier. The higher number is only 10 db away. If the notch has a
>> bit more loss, things
>>> get even tighter. This is more than just a theoretical issue.
>>> 
>>> After that you do get into the AM + PM thing. The notch is normally
>> proposed for use on
>>> floor measurements. Details are in the FCS paper by Stone back in the
>> 1970’s.  There the argument
>>> is that the noise process *must* be producing equal amounts of AM and PM
>> noise. That makes
>>> the conversion of “what I measured” to phase noise fairly easy. Close
>> in, you can indeed have
>>> processes that produce unequal amounts of AM and PM noise. Without a way
>> to separate the
>>> two, you toss a fairly large bit of doubt into the measurement.
>>> 
>>> Bob
>>> 
>>> 
 On Oct 2, 2016, at 11:03 AM, Adrian Rus > > wrote:
 
 Yes. It can be used for offsets starting some 100-200Hz. Plus, the
>> measured noise is PN+AN. Again, the only reason I wanted to share this
>> topology is its outrageous simplicity. All pluses and minuses of notch
>> filer measurement methode, remain.
 Sooner (or later) I shall share with you (after the real life
>> validation) an (again, very simple) interderometric methode.
 Adrian
 
 Sent from my BlackBerry 10 smartphone on the Orange network.

Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Chuck,
Your point is correct. I shall revert with numbers. Indeed, there are plenty of 
limitations. The intrinsic Cristal noise and the behaviour of the crystal under 
large signal are among the most worrisome.
It was incorrect opose the methode (at all) against the other known methodes.
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Chuck Harris
Sent: Sunday, October 2, 2016 19:40
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


Adrian,

Simple is nice, but if we cannot talk about the limitations
that come about because of the simplicity, without causing
offense, how can we ever know if simple is good enough?

-Chuck Harris

Adrian Rus wrote:
> Rick,
> Why hunt goose with the cannon? The post is about a simple(r) crystal notch 
> filter, nothing more and nothing less. It is not about notch filters (in 
> general) against quadrature method, nor about number of RF components or 
> about their noise floor limitation.
> It is about this notch filter against other notch filters.
> As per simplicity, to mix 2 oscillators in quadrature one need the second 
> oscillator, the high level mixer, the PLL and the baseband (FFT) analyzer.
> Best,
> Adrian
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[time-nuts] Z3801A / Z3812A leapsecond funkiness

[Mark Sims]

This morning I checked Z3812A that I had not power cycled and it is now 
reporting the pending leap second properly.   Looks like it takes over 48 hours 
for these units to recover from the bogus leapsecond condition.
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Re: [time-nuts] notch filter for close in phase noise measurement

[Chuck Harris]

Adrian,

Simple is nice, but if we cannot talk about the limitations
that come about because of the simplicity, without causing
offense, how can we ever know if simple is good enough?

-Chuck Harris

Adrian Rus wrote:
> Rick,
> Why hunt goose with the cannon? The post is about a simple(r) crystal notch 
> filter, nothing more and nothing less. It is not about notch filters (in 
> general) against quadrature method, nor about number of RF components or 
> about their noise floor limitation.
> It is about this notch filter against other notch filters.
> As per simplicity, to mix 2 oscillators in quadrature one need the second 
> oscillator, the high level mixer, the PLL and the baseband (FFT) analyzer.
> Best,
> Adrian
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Re: [time-nuts] Schematic needed

[Nick Sayer via time-nuts]

I don’t know about that particular one, but I designed an equivalent board and 
was selling it on Tindie a little while ago. I replaced it with a full-on GPS 
discipline board that powers and trims the 5680 from GPS. But if all you want 
is the power part of it, I still have the design for the simpler breakout 
board. It takes anything from 18-24 VDC in (I like to use surplus laptop power 
supplies) at 30W+ and makes the +15 and +5 supplies with two buck converters. 
It also has a self biased inverter and clock fan-out chip on board to give you 
four independent square wave outputs. I kinda think the GPS version is nicer, 
though.

> On Oct 2, 2016, at 1:21 AM, Joseph Gray  wrote:
> 
> Can someone send me the schematic for this:
> 
> https://www.febo.com/pipermail/time-nuts/2012-January/062616.html
> 
> I looked through the list archives but didn't find the schematic
> posted anywhere.
> 
> 
> Joe Gray
> W5JG
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Re: [time-nuts] notch filter for close in phase noise measurement

[Scott Stobbe]

What's the loaded Q of such a notch filter? 50 dB 100 Hz off of 10 MHz
sounds like a pretty lousy Q.

On Sunday, 2 October 2016, Bob Camp  wrote:

> Hi
>
> The issue is *not* about notch filters and if they are useful. The gotcha
> is
> that they are mainly useful far removed from carrier rather than close in.
> The
> statement “works 100 Hz off carrier” requires a *lot* of qualifiers to
> make it
> apply in real measurements.  Without getting into the limitations, it is
> very difficult
> to determine just how close to carrier you can go with a notch. That is not
> implementation specific it applies to all notches. You *do* need to get
> into the
> details.
>
> The stuff we have gone over so far is hardly an exhaustive list. There are
> many issues.
> We have yet to get into the amount of power being delivered to the crystal
> in the
> notch filter and the behavior of crystals when driven with a lot of power
> ….
>
> Bob
>
> > On Oct 2, 2016, at 12:10 PM, Adrian Rus  > wrote:
> >
> > Bob,
> > There is no issue about using or not using notch filters. We know (?)
> all of these. It is about a damn simple topology. Yes, this topology has
> its shortcomings (impedance, variation with freq and the so).
> > The math is close, but not exact.
> > I gave up here. If the topology is of no use, this is it. For me it was
> funy to _discover_ that simple topology doing a notch.
> > ‎Best,
> > Adrian
> >
> > Sent from my BlackBerry 10 smartphone on the Orange network.
> >  Original Message
> > From: Bob Camp
> > Sent: Sunday, October 2, 2016 18:35
> > To: Discussion of precise time and frequency measurement
> > Reply To: Discussion of precise time and frequency measurement
> > Subject: Re: [time-nuts] notch filter for close in phase noise
> measurement
> >
> >
> > Hi
> >
> > Ok, the next issue with the notch filter technique is the termination of
> the oscillator
> > it’s self. The notch may (or more likely not) provide a proper 50 ohm
> load at the
> > carrier frequency. Even if it is correct at the carrier, it will go off
> impedance as it
> > moves away from carrier.  You either need a pad in series with the
> oscillator (which
> > drops sensitivity) or something similar (like an isolator). The gotcha
> here is that the
> > phase noise of the device may not be the same when it is incorrectly
> terminated. The
> > issue is more significant in minimum stage devices or when the output
> stage contributes
> > to the total noise of the device.
> >
> > A bit of math:
> >
> > A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at
> 100 Hz off carrier.
> > If you have lost 20 db of energy due to the notch width, that is now
> -175 to -185 dbc / Hz.
> > If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm
> / Hz. The lower
> > number is at the KTB level without any loss in the bridge, a the
> attenuator, or noise figure in the
> > post amplifier. The higher number is only 10 db away. If the notch has a
> bit more loss, things
> > get even tighter. This is more than just a theoretical issue.
> >
> > After that you do get into the AM + PM thing. The notch is normally
> proposed for use on
> > floor measurements. Details are in the FCS paper by Stone back in the
> 1970’s.  There the argument
> > is that the noise process *must* be producing equal amounts of AM and PM
> noise. That makes
> > the conversion of “what I measured” to phase noise fairly easy. Close
> in, you can indeed have
> > processes that produce unequal amounts of AM and PM noise. Without a way
> to separate the
> > two, you toss a fairly large bit of doubt into the measurement.
> >
> > Bob
> >
> >
> >> On Oct 2, 2016, at 11:03 AM, Adrian Rus  > wrote:
> >>
> >> Yes. It can be used for offsets starting some 100-200Hz. Plus, the
> measured noise is PN+AN. Again, the only reason I wanted to share this
> topology is its outrageous simplicity. All pluses and minuses of notch
> filer measurement methode, remain.
> >> Sooner (or later) I shall share with you (after the real life
> validation) an (again, very simple) interderometric methode.
> >> Adrian
> >>
> >> Sent from my BlackBerry 10 smartphone on the Orange network.
> >> Original Message
> >> From: Bob Camp
> >> Sent: Sunday, October 2, 2016 17:54
> >> To: Discussion of precise time and frequency measurement
> >> Reply To: Discussion of precise time and frequency measurement
> >> Subject: Re: [time-nuts] notch filter for close in phase noise
> measurement
> >>
> >>
> >> Hi
> >>
> >> The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off
> the carrier frequency,
> >> it still has some depth. It might be 50 db deep, it could be 10 db
> deep. A lot depends on the
> >> crystal you have. Even if it’s only 10 db deep, the phase noise you
> measure at 100 Hz off
> >> carrier will be “off” by 10 db.
> >>
> >> Bob
> >>
> >>> On Oct 2, 2016, at 10:46 AM, Adrian Rus  > wrote:
> >>>
> >>> Hello,
> >>> The _generator_ is a reference 10MHz oscillator and the only
> calibratio

Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

The issue is *not* about notch filters and if they are useful. The gotcha is 
that they are mainly useful far removed from carrier rather than close in. The 
statement “works 100 Hz off carrier” requires a *lot* of qualifiers to make it 
apply in real measurements.  Without getting into the limitations, it is very 
difficult
to determine just how close to carrier you can go with a notch. That is not 
implementation specific it applies to all notches. You *do* need to get into 
the 
details. 

The stuff we have gone over so far is hardly an exhaustive list. There are many 
issues. 
We have yet to get into the amount of power being delivered to the crystal in 
the 
notch filter and the behavior of crystals when driven with a lot of power …. 

Bob

> On Oct 2, 2016, at 12:10 PM, Adrian Rus  wrote:
> 
> Bob,
> There is no issue about using or not using notch filters. We know (?) all of 
> these. It is about a damn simple topology. Yes, this topology has its 
> shortcomings (impedance, variation with freq and the so).
> The math is close, but not exact.
> I gave up here. If the topology is of no use, this is it. For me it was funy 
> to _discover_ that simple topology doing a notch.
> ‎Best,
> Adrian
> 
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 18:35
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
> 
> 
> Hi
> 
> Ok, the next issue with the notch filter technique is the termination of the 
> oscillator
> it’s self. The notch may (or more likely not) provide a proper 50 ohm load at 
> the
> carrier frequency. Even if it is correct at the carrier, it will go off 
> impedance as it
> moves away from carrier.  You either need a pad in series with the oscillator 
> (which
> drops sensitivity) or something similar (like an isolator). The gotcha here 
> is that the
> phase noise of the device may not be the same when it is incorrectly 
> terminated. The
> issue is more significant in minimum stage devices or when the output stage 
> contributes
> to the total noise of the device.
> 
> A bit of math:
> 
> A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at 100 Hz 
> off carrier.
> If you have lost 20 db of energy due to the notch width, that is now -175 to 
> -185 dbc / Hz.
> If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm / 
> Hz. The lower
> number is at the KTB level without any loss in the bridge, a the attenuator, 
> or noise figure in the
> post amplifier. The higher number is only 10 db away. If the notch has a bit 
> more loss, things
> get even tighter. This is more than just a theoretical issue.
> 
> After that you do get into the AM + PM thing. The notch is normally proposed 
> for use on
> floor measurements. Details are in the FCS paper by Stone back in the 1970’s. 
>  There the argument
> is that the noise process *must* be producing equal amounts of AM and PM 
> noise. That makes
> the conversion of “what I measured” to phase noise fairly easy. Close in, you 
> can indeed have
> processes that produce unequal amounts of AM and PM noise. Without a way to 
> separate the
> two, you toss a fairly large bit of doubt into the measurement.
> 
> Bob
> 
> 
>> On Oct 2, 2016, at 11:03 AM, Adrian Rus  wrote:
>> 
>> Yes. It can be used for offsets starting some 100-200Hz. Plus, the measured 
>> noise is PN+AN. Again, the only reason I wanted to share this topology is 
>> its outrageous simplicity. All pluses and minuses of notch filer measurement 
>> methode, remain.
>> Sooner (or later) I shall share with you (after the real life validation) an 
>> (again, very simple) interderometric methode.
>> Adrian
>> 
>> Sent from my BlackBerry 10 smartphone on the Orange network.
>> Original Message
>> From: Bob Camp
>> Sent: Sunday, October 2, 2016 17:54
>> To: Discussion of precise time and frequency measurement
>> Reply To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
>> 
>> 
>> Hi
>> 
>> The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off the 
>> carrier frequency,
>> it still has some depth. It might be 50 db deep, it could be 10 db deep. A 
>> lot depends on the
>> crystal you have. Even if it’s only 10 db deep, the phase noise you measure 
>> at 100 Hz off
>> carrier will be “off” by 10 db.
>> 
>> Bob
>> 
>>> On Oct 2, 2016, at 10:46 AM, Adrian Rus  wrote:
>>> 
>>> Hello,
>>> The _generator_ is a reference 10MHz oscillator and the only calibration of 
>>> the notch is to equal the oscillator freq.
>>> The basic idea of the message is its simplicity (as compared to other notch 
>>> approaches).
>>> Best regards,
>>> Adrian
>>> 
>>> Sent from my BlackBerry 10 smartphone on the Orange network.
>>> Original Message
>>> From: Bob Camp

Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Bob,
There is no issue about using or not using notch filters. We know (?) all of 
these. It is about a damn simple topology. Yes, this topology has its 
shortcomings (impedance, variation with freq and the so).
The math is close, but not exact.
I gave up here. If the topology is of no use, this is it. For me it was funy to 
_discover_ that simple topology doing a notch.
‎Best,
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Bob Camp
Sent: Sunday, October 2, 2016 18:35
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


Hi

Ok, the next issue with the notch filter technique is the termination of the 
oscillator
it’s self. The notch may (or more likely not) provide a proper 50 ohm load at 
the
carrier frequency. Even if it is correct at the carrier, it will go off 
impedance as it
moves away from carrier.  You either need a pad in series with the oscillator 
(which
drops sensitivity) or something similar (like an isolator). The gotcha here is 
that the
phase noise of the device may not be the same when it is incorrectly 
terminated. The
issue is more significant in minimum stage devices or when the output stage 
contributes
to the total noise of the device.

A bit of math:

A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at 100 Hz 
off carrier.
If you have lost 20 db of energy due to the notch width, that is now -175 to 
-185 dbc / Hz.
If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm / Hz. 
The lower
number is at the KTB level without any loss in the bridge, a the attenuator, or 
noise figure in the
post amplifier. The higher number is only 10 db away. If the notch has a bit 
more loss, things
get even tighter. This is more than just a theoretical issue.

After that you do get into the AM + PM thing. The notch is normally proposed 
for use on
floor measurements. Details are in the FCS paper by Stone back in the 1970’s.  
There the argument
is that the noise process *must* be producing equal amounts of AM and PM noise. 
That makes
the conversion of “what I measured” to phase noise fairly easy. Close in, you 
can indeed have
processes that produce unequal amounts of AM and PM noise. Without a way to 
separate the
two, you toss a fairly large bit of doubt into the measurement.

Bob


> On Oct 2, 2016, at 11:03 AM, Adrian Rus  wrote:
>
> Yes. It can be used for offsets starting some 100-200Hz. Plus, the measured 
> noise is PN+AN. Again, the only reason I wanted to share this topology is its 
> outrageous simplicity. All pluses and minuses of notch filer measurement 
> methode, remain.
> Sooner (or later) I shall share with you (after the real life validation) an 
> (again, very simple) interderometric methode.
> Adrian
>
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 17:54
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
>
>
> Hi
>
> The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off the 
> carrier frequency,
> it still has some depth. It might be 50 db deep, it could be 10 db deep. A 
> lot depends on the
> crystal you have. Even if it’s only 10 db deep, the phase noise you measure 
> at 100 Hz off
> carrier will be “off” by 10 db.
>
> Bob
>
>> On Oct 2, 2016, at 10:46 AM, Adrian Rus  wrote:
>>
>> Hello,
>> The _generator_ is a reference 10MHz oscillator and the only calibration of 
>> the notch is to equal the oscillator freq.
>> The basic idea of the message is its simplicity (as compared to other notch 
>> approaches).
>> Best regards,
>> Adrian
>>
>> Sent from my BlackBerry 10 smartphone on the Orange network.
>> Original Message
>> From: Bob Camp
>> Sent: Sunday, October 2, 2016 17:06
>> To: Discussion of precise time and frequency measurement
>> Reply To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
>>
>>
>> Hi
>>
>> Getting close to carrier with a notch filter involves a bit of calibration 
>> of the notch. It’s not
>> imposible to do, but it is a needed step. The generator you use to do the 
>> measurement has
>> to be pretty clean to get adequate data at low offsets.
>>
>> Bob
>>
>>> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
>>>
>>> Hello list,
>>> For those of you interested in phase noise measurement without using 
>>> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far 
>>> as I am concerned, all phase noise measurements use a technique to get rid 
>>> of carrier: quadrature mixing, interferometric [more on that, later] and 
>>> notch filters.
>>>
>>> The simplest way use notch filters, and the simplest n

Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Rick,
Why hunt goose with the cannon? The post is about a simple(r) crystal notch 
filter, nothing more and nothing less. It is not about notch filters (in 
general) against quadrature method, nor about number of RF components or about 
their noise floor limitation.
It is about this notch filter against other notch filters.
As per simplicity, to mix 2 oscillators in quadrature one need the second 
oscillator, the high level mixer, the PLL and the baseband (FFT) analyzer.
Best,
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Richard (Rick) Karlquist
Sent: Sunday, October 2, 2016 18:35
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


On 10/2/2016 12:56 AM, Adrian Rus wrote:
> Hello list,
> For those of you interested in phase noise measurement without using 
> fancy/dedicated gear,

There is no free lunch here.  The crystal has its own
intrinsic flicker of frequency noise.  You cannot
measure below this noise floor.  The technique
you are talking about could be useful in particular
applications, but is not a general replacement for
"dedicated gear".  I don't even see where this is
simpler than mixing two oscillators in quadrature.
In that case, the only RF component is a mixer and
everything else is audio.  Also, when using a crystal
filter, you have to be careful not to overdrive the
crystal.

Rick
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and follow the instructions there.

Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

Ok, the next issue with the notch filter technique is the termination of the 
oscillator 
it’s self. The notch may (or more likely not) provide a proper 50 ohm load at 
the 
carrier frequency. Even if it is correct at the carrier, it will go off 
impedance as it 
moves away from carrier.  You either need a pad in series with the oscillator 
(which
drops sensitivity) or something similar (like an isolator). The gotcha here is 
that the 
phase noise of the device may not be the same when it is incorrectly 
terminated. The
issue is more significant in minimum stage devices or when the output stage 
contributes
to the total noise of the device. 

A bit of math:

A good 10 MHz oscillator will be in the -155 to -165 dbc / Hz range at 100 Hz 
off carrier. 
If you have lost 20 db of energy due to the notch width, that is now -175 to 
-185 dbc / Hz. 
If the oscillator is putting out +10 dbm, that would be -165 to -175 dbm / Hz. 
The lower 
number is at the KTB level without any loss in the bridge, a the attenuator, or 
noise figure in the
post amplifier. The higher number is only 10 db away. If the notch has a bit 
more loss, things
get even tighter. This is more than just a theoretical issue. 

After that you do get into the AM + PM thing. The notch is normally proposed 
for use on 
floor measurements. Details are in the FCS paper by Stone back in the 1970’s.  
There the argument 
is that the noise process *must* be producing equal amounts of AM and PM noise. 
That makes 
the conversion of “what I measured” to phase noise fairly easy. Close in, you 
can indeed have 
processes that produce unequal amounts of AM and PM noise. Without a way to 
separate the 
two, you toss a fairly large bit of doubt into the measurement. 

Bob


> On Oct 2, 2016, at 11:03 AM, Adrian Rus  wrote:
> 
> Yes. It can be used for offsets starting some 100-200Hz. Plus, the measured 
> noise is PN+AN. Again, the only reason I wanted to share this topology is its 
> outrageous simplicity. All pluses and minuses of notch filer measurement 
> methode, remain.
> Sooner (or later) I shall share with you (after the real life validation) an 
> (again, very simple) interderometric methode.
> Adrian
> 
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 17:54
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
> 
> 
> Hi
> 
> The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off the 
> carrier frequency,
> it still has some depth. It might be 50 db deep, it could be 10 db deep. A 
> lot depends on the
> crystal you have. Even if it’s only 10 db deep, the phase noise you measure 
> at 100 Hz off
> carrier will be “off” by 10 db.
> 
> Bob
> 
>> On Oct 2, 2016, at 10:46 AM, Adrian Rus  wrote:
>> 
>> Hello,
>> The _generator_ is a reference 10MHz oscillator and the only calibration of 
>> the notch is to equal the oscillator freq.
>> The basic idea of the message is its simplicity (as compared to other notch 
>> approaches).
>> Best regards,
>> Adrian
>> 
>> Sent from my BlackBerry 10 smartphone on the Orange network.
>> Original Message
>> From: Bob Camp
>> Sent: Sunday, October 2, 2016 17:06
>> To: Discussion of precise time and frequency measurement
>> Reply To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
>> 
>> 
>> Hi
>> 
>> Getting close to carrier with a notch filter involves a bit of calibration 
>> of the notch. It’s not
>> imposible to do, but it is a needed step. The generator you use to do the 
>> measurement has
>> to be pretty clean to get adequate data at low offsets.
>> 
>> Bob
>> 
>>> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
>>> 
>>> Hello list,
>>> For those of you interested in phase noise measurement without using 
>>> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far 
>>> as I am concerned, all phase noise measurements use a technique to get rid 
>>> of carrier: quadrature mixing, interferometric [more on that, later] and 
>>> notch filters.
>>> 
>>> The simplest way use notch filters, and the simplest notch filter can be 
>>> arranged with just 3 elements:
>>> - one return loss bridge
>>> - one quartz crystal
>>> - one resistor
>>> Hook the crystal on DUT port, the oscillator to be measured on IN port, the 
>>> SA [spectrum analyzer] on OUT port and the resistor on REF port. The 
>>> resistor have to be determined by trial and error to equal the series 
>>> resistence of the crystal at series resonance. From some -50dB up, can hook 
>>> a potentiometer in parallel to the resistor[s] and fine tune for the 
>>> deepest notch.
>>> It is easy to get notches as deep as -85-90dB. The filter is useful in 
>>> close in measurements not closer than 100-200Hz from carrier. Yes, between

Re: [time-nuts] notch filter for close in phase noise measurement

[Richard (Rick) Karlquist]

On 10/2/2016 12:56 AM, Adrian Rus wrote:

Hello list,
For those of you interested in phase noise measurement without using 
fancy/dedicated gear,


There is no free lunch here.  The crystal has its own
intrinsic flicker of frequency noise.  You cannot
measure below this noise floor.  The technique
you are talking about could be useful in particular
applications, but is not a general replacement for
"dedicated gear".  I don't even see where this is
simpler than mixing two oscillators in quadrature.
In that case, the only RF component is a mixer and
everything else is audio.  Also, when using a crystal
filter, you have to be careful not to overdrive the
crystal.

Rick
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and follow the instructions there.

Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Yes. It can be used for offsets starting some 100-200Hz. Plus, the measured 
noise is PN+AN. Again, the only reason I wanted to share this topology is its 
outrageous simplicity. All pluses and minuses of notch filer measurement 
methode, remain.
Sooner (or later) I shall share with you (after the real life validation) an 
(again, very simple) interderometric methode.
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Bob Camp
Sent: Sunday, October 2, 2016 17:54
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


Hi

The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off the 
carrier frequency,
it still has some depth. It might be 50 db deep, it could be 10 db deep. A lot 
depends on the
crystal you have. Even if it’s only 10 db deep, the phase noise you measure at 
100 Hz off
carrier will be “off” by 10 db.

Bob

> On Oct 2, 2016, at 10:46 AM, Adrian Rus  wrote:
>
> Hello,
> The _generator_ is a reference 10MHz oscillator and the only calibration of 
> the notch is to equal the oscillator freq.
> The basic idea of the message is its simplicity (as compared to other notch 
> approaches).
> Best regards,
> Adrian
>
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 17:06
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
>
>
> Hi
>
> Getting close to carrier with a notch filter involves a bit of calibration of 
> the notch. It’s not
> imposible to do, but it is a needed step. The generator you use to do the 
> measurement has
> to be pretty clean to get adequate data at low offsets.
>
> Bob
>
>> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
>>
>> Hello list,
>> For those of you interested in phase noise measurement without using 
>> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far as 
>> I am concerned, all phase noise measurements use a technique to get rid of 
>> carrier: quadrature mixing, interferometric [more on that, later] and notch 
>> filters.
>>
>> The simplest way use notch filters, and the simplest notch filter can be 
>> arranged with just 3 elements:
>> - one return loss bridge
>> - one quartz crystal
>> - one resistor
>> Hook the crystal on DUT port, the oscillator to be measured on IN port, the 
>> SA [spectrum analyzer] on OUT port and the resistor on REF port. The 
>> resistor have to be determined by trial and error to equal the series 
>> resistence of the crystal at series resonance. From some -50dB up, can hook 
>> a potentiometer in parallel to the resistor[s] and fine tune for the deepest 
>> notch.
>> It is easy to get notches as deep as -85-90dB. The filter is useful in close 
>> in measurements not closer than 100-200Hz from carrier. Yes, between the 
>> notch and SA you should insert a 40-60dB amplifier. The amplifier will not 
>> degrade the flicker noise [as there is practical no carrier - see Rubiola 
>> papers], but will set the noise floor.
>> The series resonance freq have to be selected from multiple crystals; I have 
>> experienced series resonance in 10MHz crystals ranging from -300Hz to +100Hz 
>> against 10MHz sharp, and have selected a crystal resonating at +25Hz at room 
>> temperature. For exact fit you can either tune the oscillator @+25Hz, or 
>> better, thermostat the crystal; thermostating the crystal will also tune the 
>> notch to the desired freq.
>> My selected crystal was equilibrated by a series resistance of 14.7ohm. 
>> Please note, the series resistance of other 11 crystals I have tested range 
>> from 14ohm to tens of ohm.
>> Regards,
>> Adrian
>> ___
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>> and follow the instructions there.
>
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
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Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

The notch is (say) 60 db deep at the carrier frequency. At 100 Hz off the 
carrier frequency,
it still has some depth. It might be 50 db deep, it could be 10 db deep. A lot 
depends on the
crystal you have. Even if it’s only 10 db deep, the phase noise you measure at 
100 Hz off
carrier will be “off” by 10 db. 

Bob

> On Oct 2, 2016, at 10:46 AM, Adrian Rus  wrote:
> 
> Hello,
> The _generator_ is a reference 10MHz oscillator and the only calibration of 
> the notch is to equal the oscillator freq.
> The basic idea of the message is its simplicity (as compared to other notch 
> approaches).
> Best regards,
> Adrian
> 
> Sent from my BlackBerry 10 smartphone on the Orange network.
>  Original Message
> From: Bob Camp
> Sent: Sunday, October 2, 2016 17:06
> To: Discussion of precise time and frequency measurement
> Reply To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] notch filter for close in phase noise measurement
> 
> 
> Hi
> 
> Getting close to carrier with a notch filter involves a bit of calibration of 
> the notch. It’s not
> imposible to do, but it is a needed step. The generator you use to do the 
> measurement has
> to be pretty clean to get adequate data at low offsets.
> 
> Bob
> 
>> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
>> 
>> Hello list,
>> For those of you interested in phase noise measurement without using 
>> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far as 
>> I am concerned, all phase noise measurements use a technique to get rid of 
>> carrier: quadrature mixing, interferometric [more on that, later] and notch 
>> filters.
>> 
>> The simplest way use notch filters, and the simplest notch filter can be 
>> arranged with just 3 elements:
>> - one return loss bridge
>> - one quartz crystal
>> - one resistor
>> Hook the crystal on DUT port, the oscillator to be measured on IN port, the 
>> SA [spectrum analyzer] on OUT port and the resistor on REF port. The 
>> resistor have to be determined by trial and error to equal the series 
>> resistence of the crystal at series resonance. From some -50dB up, can hook 
>> a potentiometer in parallel to the resistor[s] and fine tune for the deepest 
>> notch.
>> It is easy to get notches as deep as -85-90dB. The filter is useful in close 
>> in measurements not closer than 100-200Hz from carrier. Yes, between the 
>> notch and SA you should insert a 40-60dB amplifier. The amplifier will not 
>> degrade the flicker noise [as there is practical no carrier - see Rubiola 
>> papers], but will set the noise floor.
>> The series resonance freq have to be selected from multiple crystals; I have 
>> experienced series resonance in 10MHz crystals ranging from -300Hz to +100Hz 
>> against 10MHz sharp, and have selected a crystal resonating at +25Hz at room 
>> temperature. For exact fit you can either tune the oscillator @+25Hz, or 
>> better, thermostat the crystal; thermostating the crystal will also tune the 
>> notch to the desired freq.
>> My selected crystal was equilibrated by a series resistance of 14.7ohm. 
>> Please note, the series resistance of other 11 crystals I have tested range 
>> from 14ohm to tens of ohm.
>> Regards,
>> Adrian
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>> and follow the instructions there.
> 
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Re: [time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Hello,
The _generator_ is a reference 10MHz oscillator and the only calibration of the 
notch is to equal the oscillator freq.
The basic idea of the message is its simplicity (as compared to other notch 
approaches).
Best regards,
Adrian

Sent from my BlackBerry 10 smartphone on the Orange network.
  Original Message
From: Bob Camp
Sent: Sunday, October 2, 2016 17:06
To: Discussion of precise time and frequency measurement
Reply To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] notch filter for close in phase noise measurement


Hi

Getting close to carrier with a notch filter involves a bit of calibration of 
the notch. It’s not
imposible to do, but it is a needed step. The generator you use to do the 
measurement has
to be pretty clean to get adequate data at low offsets.

Bob

> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
>
> Hello list,
> For those of you interested in phase noise measurement without using 
> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far as 
> I am concerned, all phase noise measurements use a technique to get rid of 
> carrier: quadrature mixing, interferometric [more on that, later] and notch 
> filters.
>
> The simplest way use notch filters, and the simplest notch filter can be 
> arranged with just 3 elements:
> - one return loss bridge
> - one quartz crystal
> - one resistor
> Hook the crystal on DUT port, the oscillator to be measured on IN port, the 
> SA [spectrum analyzer] on OUT port and the resistor on REF port. The resistor 
> have to be determined by trial and error to equal the series resistence of 
> the crystal at series resonance. From some -50dB up, can hook a potentiometer 
> in parallel to the resistor[s] and fine tune for the deepest notch.
> It is easy to get notches as deep as -85-90dB. The filter is useful in close 
> in measurements not closer than 100-200Hz from carrier. Yes, between the 
> notch and SA you should insert a 40-60dB amplifier. The amplifier will not 
> degrade the flicker noise [as there is practical no carrier - see Rubiola 
> papers], but will set the noise floor.
> The series resonance freq have to be selected from multiple crystals; I have 
> experienced series resonance in 10MHz crystals ranging from -300Hz to +100Hz 
> against 10MHz sharp, and have selected a crystal resonating at +25Hz at room 
> temperature. For exact fit you can either tune the oscillator @+25Hz, or 
> better, thermostat the crystal; thermostating the crystal will also tune the 
> notch to the desired freq.
> My selected crystal was equilibrated by a series resistance of 14.7ohm. 
> Please note, the series resistance of other 11 crystals I have tested range 
> from 14ohm to tens of ohm.
> Regards,
> Adrian
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Re: [time-nuts] notch filter for close in phase noise measurement

[Bob Camp]

Hi

Getting close to carrier with a notch filter involves a bit of calibration of 
the notch. It’s not 
imposible to do, but it is a needed step. The generator you use to do the 
measurement has
to be pretty clean to get adequate data at low offsets. 

Bob

> On Oct 2, 2016, at 3:56 AM, Adrian Rus  wrote:
> 
> Hello list,
> For those of you interested in phase noise measurement without using 
> fancy/dedicated gear, here you are the way I have got. Disclaimer: as far as 
> I am concerned, all phase noise measurements use a technique to get rid of 
> carrier: quadrature mixing, interferometric [more on that, later] and notch 
> filters.
> 
> The simplest way use notch filters, and the simplest notch filter can be 
> arranged with just 3 elements:
> - one return loss bridge
> - one quartz crystal
> - one resistor
> Hook the crystal on DUT port, the oscillator to be measured on IN port, the 
> SA [spectrum analyzer] on OUT port and the resistor on REF port. The resistor 
> have to be determined by trial and error to equal the series resistence of 
> the crystal at series resonance. From some -50dB up, can hook a potentiometer 
> in parallel to the resistor[s] and fine tune for the deepest notch.
> It is easy to get notches as deep as -85-90dB. The filter is useful in close 
> in measurements not closer than 100-200Hz from carrier. Yes, between the 
> notch and SA you should insert a 40-60dB amplifier. The amplifier will not 
> degrade the flicker noise [as there is practical no carrier - see Rubiola 
> papers], but will set the noise floor.
> The series resonance freq have to be selected from multiple crystals; I have 
> experienced series resonance in 10MHz crystals ranging from -300Hz to +100Hz 
> against 10MHz sharp, and have selected a crystal resonating at +25Hz at room 
> temperature. For exact fit you can either tune the oscillator @+25Hz, or 
> better, thermostat the crystal; thermostating the crystal will also tune the 
> notch to the desired freq.
> My selected crystal was equilibrated by a series resistance of 14.7ohm. 
> Please note, the series resistance of other 11 crystals I have tested range 
> from 14ohm to tens of ohm.
> Regards,
> Adrian
> ___
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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[time-nuts] notch filter for close in phase noise measurement

[Adrian Rus]

Hello list,
For those of you interested in phase noise measurement without using 
fancy/dedicated gear, here you are the way I have got. Disclaimer: as far as I 
am concerned, all phase noise measurements use a technique to get rid of 
carrier: quadrature mixing, interferometric [more on that, later] and notch 
filters.

The simplest way use notch filters, and the simplest notch filter can be 
arranged with just 3 elements:
- one return loss bridge
- one quartz crystal
- one resistor
Hook the crystal on DUT port, the oscillator to be measured on IN port, the SA 
[spectrum analyzer] on OUT port and the resistor on REF port. The resistor have 
to be determined by trial and error to equal the series resistence of the 
crystal at series resonance. From some -50dB up, can hook a potentiometer in 
parallel to the resistor[s] and fine tune for the deepest notch.
It is easy to get notches as deep as -85-90dB. The filter is useful in close in 
measurements not closer than 100-200Hz from carrier. Yes, between the notch and 
SA you should insert a 40-60dB amplifier. The amplifier will not degrade the 
flicker noise [as there is practical no carrier - see Rubiola papers], but will 
set the noise floor.
The series resonance freq have to be selected from multiple crystals; I have 
experienced series resonance in 10MHz crystals ranging from -300Hz to +100Hz 
against 10MHz sharp, and have selected a crystal resonating at +25Hz at room 
temperature. For exact fit you can either tune the oscillator @+25Hz, or 
better, thermostat the crystal; thermostating the crystal will also tune the 
notch to the desired freq.
My selected crystal was equilibrated by a series resistance of 14.7ohm. Please 
note, the series resistance of other 11 crystals I have tested range from 14ohm 
to tens of ohm.
Regards,
Adrian
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Re: [time-nuts] Schematic needed

[Bob Camp]

Hi

Be *very* careful hooking up to a 5680. There are an unfortunately large 
number of pinouts and power options. As far as anybody knows, there is
no easy way to figure out what you have from the outside of the unit.  Since
the connections are incompatible with each other, the “try it and see” approach
is not recommended. 

Bob

> On Oct 2, 2016, at 4:21 AM, Joseph Gray  wrote:
> 
> Can someone send me the schematic for this:
> 
> https://www.febo.com/pipermail/time-nuts/2012-January/062616.html
> 
> I looked through the list archives but didn't find the schematic
> posted anywhere.
> 
> 
> Joe Gray
> W5JG
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[time-nuts] Schematic needed

[Joseph Gray]

Can someone send me the schematic for this:

https://www.febo.com/pipermail/time-nuts/2012-January/062616.html

I looked through the list archives but didn't find the schematic
posted anywhere.


Joe Gray
W5JG
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Re: [time-nuts] Caroliine .. I need to move on

[David]

I was thinking message from Cave Johnson.

On Sat, 1 Oct 2016 23:24:09 -0700, you wrote:

>Hurricane I believe
>
>-=Bryan=-
>
>> From: jim77...@gmail.com
>> 
>> Well I'm intrigued!
>> 
>> On 2 October 2016 at 15:53, Ian Stirling  wrote:
>> 
>> > going to the emergency place
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