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

[Charles Steinmetz]

Bill wrote:


A switching regulator without the steep (and noisy) transients of
today's switchers.


Well, don't get too giddy about how quiet the scheme is .  HP 
warned that if you use the same 12v (nominal) power supply for the oven 
control and crystal oscillator circuits, you need to add extra filtering 
to the oscillator power line to avoid injecting switching noise into the 
sensitive oscillator circuitry.


I always use separate voltage regulators for the oven control and 
crystal oscillator circuits when I build a 10544 or 10811 into a 
project, and I have modified HP instruments by adding an additional 
regulator for the oscillator section when they had 10544s installed, to 
good effect.  Even then, a small amount of switching noise is induced 
into the oscillator section internally to the 10544.


That said, it is a simple and robust system that performs quite well in 
general.


Best regards,

Charles


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

[Bill Hawkins]

Thank you, Charles.

What a clever way to minimize the power dissipation in Q4 with the
components of the day.

A switching regulator without the steep (and noisy) transients of
today's switchers.

Bill Hawkins 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles
Steinmetz
Sent: Monday, January 08, 2018 10:21 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] AM vs PM noise of signal sources

Bill wrote:

> What does the unijunction 2N2646 do in the oven controller?

For the following discussion, you need to refer to the *corrected*
schematic I mentioned in my last post.  If you are looking at the HP
schematic, you will wonder how the hell it works (and it wouldn't, if HP
actually built them as they drew it).

The 10544 oven control circuit uses pulse-width modulation to control
the heater in a "bang-bang" manner rather than a smooth proportional
manner.  UJT A3Q3 forms a relaxation oscillator (along with A3C1 and
A3R10), with a period of ~250uS (frequency ~4kHz) and a voltage span
from ~0v to ~8v.

This positive-going ramp is applied to the base of Darlington A3Q2
(MPSA12), which is 1/2 of a differential pair current switch along with
A3Q1 (2N3904).

The thermistor and associated op-amp circuitry set a threshold voltage
between ground and about 7v at the base of Q1.  After the relaxation
oscillator resets to ~0v, current flows through A3Q1 and A3R8, pulling
the base of Darlington A3Q4 negative and turning it on to saturation. 
The collector of A3Q4 therefore applies essentially the full oven heater
supply voltage from Pin 14 (nominally 24v) to the high side of the
heater.

The oscillator voltage ramps positive toward its ~8v maximum (the
trigger point of UJT A3Q3).  When the emitter of A3Q2, which is two
diode drops below the ramp voltage, exceeds the voltage at the emitter
of Q1 (as set by the thermistor and A3U1), Q2 steals the current that
has been flowing in A3Q1 and turns Darlington switch A3Q4 off, which
interrupts the current flowing through the heater.  Some time later
(about 250uS after the previous reset), the oscillator voltage reaches
the trigger point of the UJT and it resets the voltage on A3C1 to ~0v
and the cycle begins again.

Thus, every ~250uS the heater is on for a time (set by the thermistor
circuitry) and off for the remainder of the ~250uS.  This switching
action can be seen at the "Oven Monitor", Pin 11 (but note that the
instrument may have a capacitor to ground on the mother card side of the
oven monitor, to integrate the switching waveform for use by the
instrument's health monitor).

Best regards,

Charles


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

[Charles Steinmetz]

Bill wrote:


What does the unijunction 2N2646 do in the oven controller?


For the following discussion, you need to refer to the *corrected* 
schematic I mentioned in my last post.  If you are looking at the HP 
schematic, you will wonder how the hell it works (and it wouldn't, if HP 
actually built them as they drew it).


The 10544 oven control circuit uses pulse-width modulation to control 
the heater in a "bang-bang" manner rather than a smooth proportional 
manner.  UJT A3Q3 forms a relaxation oscillator (along with A3C1 and 
A3R10), with a period of ~250uS (frequency ~4kHz) and a voltage span 
from ~0v to ~8v.


This positive-going ramp is applied to the base of Darlington A3Q2 
(MPSA12), which is 1/2 of a differential pair current switch along with 
A3Q1 (2N3904).


The thermistor and associated op-amp circuitry set a threshold voltage 
between ground and about 7v at the base of Q1.  After the relaxation 
oscillator resets to ~0v, current flows through A3Q1 and A3R8, pulling 
the base of Darlington A3Q4 negative and turning it on to saturation. 
The collector of A3Q4 therefore applies essentially the full oven heater 
supply voltage from Pin 14 (nominally 24v) to the high side of the heater.


The oscillator voltage ramps positive toward its ~8v maximum (the 
trigger point of UJT A3Q3).  When the emitter of A3Q2, which is two 
diode drops below the ramp voltage, exceeds the voltage at the emitter 
of Q1 (as set by the thermistor and A3U1), Q2 steals the current that 
has been flowing in A3Q1 and turns Darlington switch A3Q4 off, which 
interrupts the current flowing through the heater.  Some time later 
(about 250uS after the previous reset), the oscillator voltage reaches 
the trigger point of the UJT and it resets the voltage on A3C1 to ~0v 
and the cycle begins again.


Thus, every ~250uS the heater is on for a time (set by the thermistor 
circuitry) and off for the remainder of the ~250uS.  This switching 
action can be seen at the "Oven Monitor", Pin 11 (but note that the 
instrument may have a capacitor to ground on the mother card side of the 
oven monitor, to integrate the switching waveform for use by the 
instrument's health monitor).


Best regards,

Charles


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

[Bill Hawkins]

Charles,

What does the unijunction 2N2646 do in the oven controller?

Bill Hawkins
 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles
Steinmetz
Sent: Monday, January 08, 2018 7:50 AM

Also, note that the HP schematics of the 10544 have some errors that
were (as far as I can tell) never corrected by HP.  I posted a corrected
and annotated schematic to Didier's site (ko4bb.com).  Here's a link:



Best regards,

Charles


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

[Ulrich Rohde via time-nuts]

Hi from Florida (it is atypical cool),ly 
 
`
Ref 1 is really  only good for an insight but to use it makes no sens and the 
names in ref 2 are out of order, that makes no difference.
 
Ulrich 
 
 
In a message dated 1/8/2018 9:02:47 AM Eastern Standard Time, att...@kinali.ch 
writes:
 Moin

Disclaimer: I am by far not an expert in oscillators. Please correct me if
I am wrong.

I am putting my replies to a few mails together into one, as not to clutter
the mailinglist too much.

On Sat, 6 Jan 2018 19:53:20 +1300
donald collie  wrote:

> So to be lowest noise, an oscillator should have the highest Q resonator
> possible in its feedback loop, operate in class "A" [for maximum
> linearity], and utilise active amplifier device(s) that contribute the
> least noise [both amplitude, or 1/f], and phase. 

Actually, it shouldn't. At least not if you want low phase noise.
The sensitivity of the output phase noise to the internal noise sources
changes during the period of the oscillator. AFAIK this has been first
noted by Hajimiri and Lee in [1], you can also find it mentioned in [2].
The small problem with that is, that it will lead to an increase of AM
noise, which in turn is turned into 1/f^2 and 1/f^3 PM noise through
the oscillator.

Also, you might want to back down a bit on the loaded Q, if you can
significantly improve the noise performance of the sustaining amplifier,
by better matching. (Gregory Weaver mentioned this during a discussion)

> Resistors in the oscillator carrying DC make 1/f noise - the best in this
> respect are the metal type, I think - so use metal resistors or WW.

The 1/f noise of resistors is lower than that of the semiconductors
involved, unless you are using carbon resistors. Hence most people
just simply ignore it. The commonly accepted theory is, that the 1/f
noise in resistors comes from the electron traps at material faults.
In carbon resistors, these are formed by the edges of the carbon particles.
In other these are formed by the way how the resistive material is deposited.
Hence thin-film and metal-foil have the lowest 1/f noise.

On Sat, 6 Jan 2018 20:12:16 -0600
Dana Whitlow  wrote:

> 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.
> Is anybody reading this aware of what the truth really is?

The truth is complicated. There are so many effects that one has to
analyse and keep track that it's hard to say which one dominates in
a design, without doing extensive calculations or simulations.
At least that's my impressen, when I read papers on noise in electronics.

On Mon, 8 Jan 2018 01:02:11 +1300
donald collie  wrote:

> Does any limiter, soft or hard, [and perhaps any nonlinearity of power
> term 3 or greater in the amplifier of an oscillator] cause the "baseband
> 1/f noise to translate up to the resonator frequency [a form of
> crossmodulation]?.

The upconversion happens regardless of the limiting circuit. It stems from
the sustaining amplifier being non-linear. Even running a transistor completely
in a class A configuration will lead to upconversion, because not all the noise
sources are at places where the transfer function through the transistor to the
output is linear.

> I wonder this because
> phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
> active device, or power supply. 

I do not understand this question. Noise looks "the same" for all devices.
Their only difference is the relative levels of 1/f^a noise. As such, it is
hard (impossible?) to say which device causes the noise at the output of
an oscillator by just looking at its output.

> Ceramic caps, and resonators [I`m thinking
> of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
> is associated with dc passing through resistors, or semiconductors.

1/f noise is generally associatiated with semiconductors and (carbon)
resistors, yes. But the crystal itself has its own 1/f noise and depending
on your circuit that might be actually the limiting factor and not the
electronic circuit.

Also keep in mind that a lot of electronic components are electro-mechanical
in nature. Ie they convert mechanical noise (aka vibrations) into electrical
noise. A prime culprit of this behaviour are capacitors and inductors, but
also semiconductors are known for this.

> So the
> best way to go might be to have a very linear amplifier, which exhibits
> very low noise [perhaps 150dB below the operating level], with an AGC loop,
> that sets the operating levela little below the level at which the amp
> starts to clip - this could be done with a thermistor to avoid the AGC loop
> altering the [optimised] operating conditions of the amp. Alternatively you
> might be able to use a tetrode device like a dual gate MOSFET, and apply
> the AGC to the second gate. Thus you could keep the extremely linear amp
> 

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

[Attila Kinali]

Moin

Disclaimer: I am by far not an expert in oscillators. Please correct me if
I am wrong.

I am putting my replies to a few mails together into one, as not to clutter
the mailinglist too much.

On Sat, 6 Jan 2018 19:53:20 +1300
donald collie  wrote:

> So to be lowest noise, an oscillator should have the highest Q resonator
> possible in its feedback loop, operate in class "A" [for maximum
> linearity], and utilise active amplifier device(s) that contribute the
> least noise [both amplitude, or 1/f], and phase. 

Actually, it shouldn't. At least not if you want low phase noise.
The sensitivity of the output phase noise to the internal noise sources
changes during the period of the oscillator. AFAIK this has been first
noted by Hajimiri and Lee in [1], you can also find it mentioned in [2].
The small problem with that is, that it will lead to an increase of AM
noise, which in turn is turned into 1/f^2 and 1/f^3 PM noise through
the oscillator.

Also, you might want to back down a bit on the loaded Q, if you can
significantly improve the noise performance of the sustaining amplifier,
by better matching. (Gregory Weaver mentioned this during a discussion)

> Resistors in the oscillator carrying DC make 1/f noise - the best in this
> respect are the metal type, I think - so use metal resistors or WW.

The 1/f noise of resistors is lower than that of the semiconductors
involved, unless you are using carbon resistors. Hence most people
just simply ignore it. The commonly accepted theory is, that the 1/f
noise in resistors comes from the electron traps at material faults.
In carbon resistors, these are formed by the edges of the carbon particles.
In other these are formed by the way how the resistive material is deposited.
Hence thin-film and metal-foil have the lowest 1/f noise.

On Sat, 6 Jan 2018 20:12:16 -0600
Dana Whitlow  wrote:

> 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.
> Is anybody reading this aware of what the truth really is?

The truth is complicated. There are so many effects that one has to
analyse and keep track that it's hard to say which one dominates in
a design, without doing extensive calculations or simulations.
At least that's my impressen, when I read papers on noise in electronics.

On Mon, 8 Jan 2018 01:02:11 +1300
donald collie  wrote:

> Does any limiter, soft or hard, [and perhaps any nonlinearity  of power
> term 3 or greater in the amplifier of an oscillator] cause the "baseband
> 1/f noise to translate up to the resonator frequency [a form of
> crossmodulation]?.

The upconversion happens regardless of the limiting circuit. It stems from
the sustaining amplifier being non-linear. Even running a transistor completely
in a class A configuration will lead to upconversion, because not all the noise
sources are at places where the transfer function through the transistor to the
output is linear.

> I wonder this because
> phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
> active device, or power supply. 

I do not understand this question. Noise looks "the same" for all devices.
Their only difference is the relative levels of 1/f^a noise. As such, it is
hard (impossible?) to say which device causes the noise at the output of
an oscillator by just looking at its output.

> Ceramic caps, and resonators [I`m thinking
> of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
> is associated with dc passing through resistors, or semiconductors.

1/f noise is generally associatiated with semiconductors and (carbon)
resistors, yes. But the crystal itself has its own 1/f noise and depending
on your circuit that might be actually the limiting factor and not the
electronic circuit.

Also keep in mind that a lot of electronic components are electro-mechanical
in nature. Ie they convert mechanical noise (aka vibrations) into electrical
noise. A prime culprit of this behaviour are capacitors and inductors, but
also semiconductors are known for this.

> So the
> best way to go might be to have a very linear amplifier, which exhibits
> very low noise [perhaps 150dB below the operating level], with an AGC loop,
> that sets the operating levela little below the level at which the amp
> starts to clip - this could be done with a thermistor to avoid the AGC loop
> altering the [optimised] operating conditions of the amp. Alternatively you
> might be able to use a tetrode device like a dual gate MOSFET, and apply
> the AGC to the second gate. Thus you could keep the extremely linear amp
> extremely linear. [150dB below 1Volt RMS is 0.032uV RMS].

If you google for Rohde/Poddar and noise/oscillator, you will find quite
a few papers and articles on how to build low-noise oscillators that are
only limited by the thermal noise in the 50Ω source resistance, Ie oscillators
that 

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

[Charles Steinmetz]

Don wrote:


I`m looking at the circuit of an HP10544 oscillator - can anybody confirm,
please, if the HP transistor types 53-20, and 54-215 have commercial
equivalents?


54-215 (full HP part number 1854-0215) is the ubiquitous 2N3904.

53-20 (full HP part number 1853-0020) is 2N3702.  2N4403 is an 
equivalent if 3702 is hard to find.


Also, note that the HP schematics of the 10544 have some errors that 
were (as far as I can tell) never corrected by HP.  I posted a corrected 
and annotated schematic to Didier's site (ko4bb.com).  Here's a link:




Best regards,

Charles


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

[donald collie]

 Wien bridge and bridged T oscillators often use a thermistor  [lamp] to
set the  amplitude below saturation, for low distortion, but i`ve seen the
diode AGC method used.
Conversely, you could use a thermistor to set the output of a crystal or
L/C oscillator. One other method seems to be to let the oscillator limit
somehow, and then rely on the filtering action of the resonator to purify
the output. Is this shutting the barn door, after the horse has egreased,
though - especially with close in phase noise, which doesn`t get filtered
as much?. One possible advantage of the thermistor approach would be that
the gain can be reduced without changing the active device`s operating
point, which may have been chosen after conciddering  number of factors :
Oscillator amplitude, best phase noise , linearity. etc. Thankyou Jeff for
pointing out that for best results, maximum output is not always sought.
Looking at my H'P 10544A circuit I see a slow, diode AGC, and a single
2N4125 [?] oscillator transistor with AGC applied to its emitter. I guess
that the voltage gain through the crystal means that the oscillator
produces the expected output with this transistor loafing along, causing
the PM mechanism[s] in this transistor not to be as large as they might
well be if the oscillator was limiting.
Cheers!...Don C.
P.S.: I`m not learned, just enthusiastic ;-)

Virus-free.
www.avg.com

<#m_5189967835349033426_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Mon, Jan 8, 2018 at 3:08 PM, Gerhard Hoffmann  wrote:

>
>
> Am 07.01.2018 um 17:05 schrieb Arnold Tibus:
>
>>
>> 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 ;-)  )
>>
>>
> He shares that fate with a certain Mr. Seimens and the famous Oscar Meyer
> Weiner.
> That must be a German->American sound shift, some kind of extension to
> Grimm's law.
>
> There also was a Mr. Hamming, but there never was a Mr. Hanning, at least
> not
> in the business of weighting contents of time series.
>
> That guy with the window function was one Mr. Julius von Hann, an
> Austrian Meteorologist. It is therefore the Hann window.
>
> 
>
> cheers, Gerhard
>
>
>
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Re: [time-nuts] AM vs PM noise of signal sources

[Gerhard Hoffmann]

Am 07.01.2018 um 17:05 schrieb Arnold Tibus:


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 ;-)  )



He shares that fate with a certain Mr. Seimens and the famous Oscar 
Meyer Weiner.
That must be a German->American sound shift, some kind of extension to 
Grimm's law.


There also was a Mr. Hamming, but there never was a Mr. Hanning, at 
least not

in the business of weighting contents of time series.

That guy with the window function was one Mr. Julius von Hann, an
Austrian Meteorologist. It is therefore the Hann window.

<    https://en.wikipedia.org/wiki/Julius_von_Hann    >

cheers, Gerhard


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

[donald collie]

I`m looking at the circuit of an H/P10544 oscillator - can anybody confirm,
please, if the H'P transistor types : 53-20, and 54-215 have commercial
equivalents?
Thankyou


...Don.

On Mon, Jan 8, 2018 at 1:02 AM, donald collie <donaldbcol...@gmail.com>
wrote:

> Does any limiter, soft or hard, [and perhaps any nonlinearity  of power
> term 3 or greater in the amplifier of an oscillator] cause the "baseband
> 1/f noise to translate up to the resonator frequency [a form of
> crossmodulation]?. I wonder this because
> phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
> active device, or power supply. Ceramic caps, and resonators [I`m thinking
> of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
> is associated with dc passing through resistors, or semiconductors. So the
> best way to go might be to have a very linear amplifier, which exhibits
> very low noise [perhaps 150dB below the operating level], with an AGC loop,
> that sets the operating levela little below the level at which the amp
> starts to clip - this could be done with a thermistor to avoid the AGC loop
> altering the [optimised] operating conditions of the amp. Alternatively you
> might be able to use a tetrode device like a dual gate MOSFET, and apply
> the AGC to the second gate. Thus you could keep the extremely linear amp
> extremely linear. [150dB below 1Volt RMS is 0.032uV RMS].
> Cheers!.
> 
> ...Don ZL4GX
>
>
> <http://www.avg.com/email-signature?utm_medium=email_source=link_campaign=sig-email_content=webmail>
>  Virus-free.
> www.avg.com
> <http://www.avg.com/email-signature?utm_medium=email_source=link_campaign=sig-email_content=webmail>
> <#m_3433364989741243603_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoo...@gmail.com>
> 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.
>> Is anybody reading this aware of what the truth really is?
>>
>> Dana
>>
>>
>> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <
>> mag...@rubidium.dyndns.org
>> > wrote:
>>
>> >
>> >
>> > On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
>> > >> --
>> > >>
>> > >> Message: 2
>> > >> Date: Sat, 6 Jan 2018 09:19:31 -0500
>> > >> From: Bob kb8tq <kb...@n1k.org>
>> > >> To: Discussion of precise time and frequency measurement
>> > >>  <time-nuts@febo.com>
>> > >> Subject: Re: [time-nuts] AM vs PM noise of signal sources
>> > >> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
>> > >> Content-Type: text/plain;charset=utf-8
>> > >>
>> > >> Hi
>> > >>
>> > >> The key point missing is the fact that any real oscillator must have
>> > >> a limiter
>> > >> in the loop. Otherwise it will “create one” by going over the max
>> > >> output of this or
>> > >> that amplifier. To the degree that the limiter has issues (limits
>> > >> poorly) you will get
>> > >> AM noise.
>> > >
>> > > Hmm.  Not strictly true.  One can also use an AGC loop, like a wein
>> > > bridge oscillator.  That said, some kind of softish limiter is
>> commonly
>> > > used.
>> >
>> > Regardless what non-linear mechanism in play, this remains a non-linear
>> > mechanism that achieves the goal. Choose wisely.
>> >
>> > Cheers,
>> > Magnus
>> > ___
>> > 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.
>> >
>> ___
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>> ailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

> On Jan 7, 2018, at 12:26 PM, jimlux  wrote:
> 
> On 1/7/18 8:05 AM, Arnold Tibus 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.
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.comgents,
>>> To unsubscribe, go to 
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>> 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 ;-)  )
> 
> 
> 
> 
> 
> Ah yes. And I imagine then that the pronounciation should be in english “veen"

This time of year, it’s the word on the label right after the term Gluh. I tend 
to never / ever
get that one right either. It always comes out Glugh …. can’t think of why :)

The Wien bridge is a very “low Q” resonator approach. It will give you 
amazingly low distortion 
(low harmonics) at the same time it does pretty poor amplitude and phase noise. 

Bob


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

[jimlux]

On 1/7/18 8:05 AM, Arnold Tibus 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 ;-)  )







Ah yes. And I imagine then that the pronounciation should be in english 
"veen"

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

[Dr. Ulrich L. Rohde via time-nuts]

You are simply correct !

Ulrich 

Sent from my iPhone

> On Jan 7, 2018, at 11:05 AM, Arnold Tibus  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.
>> ___
>> time-nuts mailing list -- time-nuts@febo.comgents,
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> 
> 
> 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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Re: [time-nuts] AM vs PM noise of signal sources

[Dr. Ulrich L. Rohde via time-nuts]

It is a Wien bridge

Sent from my iPhone

> On Jan 7, 2018, at 10:33 AM, jimlux  wrote:
> 
>> 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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Re: [time-nuts] AM vs PM noise of signal sources

[Arnold Tibus]

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

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

[Bob kb8tq]

Hi

> On Jan 6, 2018, at 9:12 PM, Dana Whitlow <k8yumdoo...@gmail.com> 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.
> Is anybody reading this aware of what the truth really is?

If you have a “very slow AGC” it will only take care of AM noise *inside* it’s 
bandwidth. You very much want to eliminate that noise rather than just let
it roar on down the road. AGC plus limiter works mainly because you are 
trying to take care of close in noise with the AGC and you let the limiter
handle the rest. If you build an AGC plus limiter oscillator it’s pretty simple
to adjust the AGC into various regions. It’s a “look at the data and adjust”
sort of process. 

Bob


> 
> Dana
> 
> 
> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <mag...@rubidium.dyndns.org
>> wrote:
> 
>> 
>> 
>> On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
>>>> --
>>>> 
>>>> Message: 2
>>>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>>>> From: Bob kb8tq <kb...@n1k.org>
>>>> To: Discussion of precise time and frequency measurement
>>>> <time-nuts@febo.com>
>>>> Subject: Re: [time-nuts] AM vs PM noise of signal sources
>>>> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
>>>> Content-Type: text/plain;charset=utf-8
>>>> 
>>>> Hi
>>>> 
>>>> The key point missing is the fact that any real oscillator must have
>>>> a limiter
>>>> in the loop. Otherwise it will “create one” by going over the max
>>>> output of this or
>>>> that amplifier. To the degree that the limiter has issues (limits
>>>> poorly) you will get
>>>> AM noise.
>>> 
>>> Hmm.  Not strictly true.  One can also use an AGC loop, like a wein
>>> bridge oscillator.  That said, some kind of softish limiter is commonly
>>> used.
>> 
>> Regardless what non-linear mechanism in play, this remains a non-linear
>> mechanism that achieves the goal. Choose wisely.
>> 
>> Cheers,
>> Magnus
>> ___
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>> 
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

> On Jan 7, 2018, at 8:02 AM, Ulrich Rohde via time-nuts <time-nuts@febo.com> 
> wrote:
> 
> This and related topics are  presented in :
>  
>  
> [BOOK] The design of modern microwave oscillators for wireless applications: 
> theory and optimizationUL Rohde, AK Poddar, G Böck - 2005 - books.google.com
> Delivering the best possible solution for phase noise and output power 
> efficiency in 
> oscillators This complete and thorough analysis of microwave oscillators 
> investigates all 
> aspects of design, with particular emphasis on operating conditions, choice 
> of resonators 
> and transistors, phase noise, and output power. It covers both bipolar 
> transistors and FETs. 
> Following the authors' guidance, readers learn how to design microwave 
> oscillators and …
>   Cited by 198 Related articles All 6 versions 
>  
>  
>  
>  
> 73 de Ulrich , N1 UL 


…. There’s also a few papers out there on the topic. I seem to remember sitting
through a few you wrote .

Bob

> In a message dated 1/7/2018 7:07:56 AM Eastern Standard Time, 
> donaldbcol...@gmail.com writes:
> 
>  
> Does any limiter, soft or hard, [and perhaps any nonlinearity of power
> term 3 or greater in the amplifier of an oscillator] cause the "baseband
> 1/f noise to translate up to the resonator frequency [a form of
> crossmodulation]?. I wonder this because
> phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
> active device, or power supply. Ceramic caps, and resonators [I`m thinking
> of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
> is associated with dc passing through resistors, or semiconductors. So the
> best way to go might be to have a very linear amplifier, which exhibits
> very low noise [perhaps 150dB below the operating level], with an AGC loop,
> that sets the operating levela little below the level at which the amp
> starts to clip - this could be done with a thermistor to avoid the AGC loop
> altering the [optimised] operating conditions of the amp. Alternatively you
> might be able to use a tetrode device like a dual gate MOSFET, and apply
> the AGC to the second gate. Thus you could keep the extremely linear amp
> extremely linear. [150dB below 1Volt RMS is 0.032uV RMS].
> Cheers!Don
> ZL4GX
> 
> <http://www.avg.com/email-signature?utm_medium=email_source=link_campaign=sig-email_content=webmail>
> Virus-free.
> www.avg.com
> <http://www.avg.com/email-signature?utm_medium=email_source=link_campaign=sig-email_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> 
> On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoo...@gmail.com> 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.
>> Is anybody reading this aware of what the truth really is?
>> 
>> Dana
>> 
>> 
>> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <
>> mag...@rubidium.dyndns.org
>>> wrote:
>> 
>>> 
>>> 
>>> On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
>>>>> --
>>>>> 
>>>>> Message: 2
>>>>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>>>>> From: Bob kb8tq <kb...@n1k.org>
>>>>> To: Discussion of precise time and frequency measurement
>>>>> <time-nuts@febo.com>
>>>>> Subject: Re: [time-nuts] AM vs PM noise of signal sources
>>>>> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
>>>>> Content-Type: text/plain; charset=utf-8
>>>>> 
>>>>> Hi
>>>>> 
>>>>> The key point missing is the fact that any real oscillator must have
>>>>> a limiter
>>>>> in the loop. Otherwise it will “create one” by going over the max
>>>>> output of t

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

[Ulrich Rohde via time-nuts]

This and related topics are  presented in :
 
 
[BOOK] The design of modern microwave oscillators for wireless applications: 
theory and optimizationUL Rohde, AK Poddar, G Böck - 2005 - books.google.com
Delivering the best possible solution for phase noise and output power 
efficiency in 
oscillators This complete and thorough analysis of microwave oscillators 
investigates all 
aspects of design, with particular emphasis on operating conditions, choice of 
resonators 
and transistors, phase noise, and output power. It covers both bipolar 
transistors and FETs. 
Following the authors' guidance, readers learn how to design microwave 
oscillators and …
  Cited by 198 Related articles All 6 versions 
 
 
 
 
73 de Ulrich , N1 UL 
In a message dated 1/7/2018 7:07:56 AM Eastern Standard Time, 
donaldbcol...@gmail.com writes:

 
 Does any limiter, soft or hard, [and perhaps any nonlinearity of power
term 3 or greater in the amplifier of an oscillator] cause the "baseband
1/f noise to translate up to the resonator frequency [a form of
crossmodulation]?. I wonder this because
phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
active device, or power supply. Ceramic caps, and resonators [I`m thinking
of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
is associated with dc passing through resistors, or semiconductors. So the
best way to go might be to have a very linear amplifier, which exhibits
very low noise [perhaps 150dB below the operating level], with an AGC loop,
that sets the operating levela little below the level at which the amp
starts to clip - this could be done with a thermistor to avoid the AGC loop
altering the [optimised] operating conditions of the amp. Alternatively you
might be able to use a tetrode device like a dual gate MOSFET, and apply
the AGC to the second gate. Thus you could keep the extremely linear amp
extremely linear. [150dB below 1Volt RMS is 0.032uV RMS].
Cheers!Don
ZL4GX

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On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoo...@gmail.com> 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.
> Is anybody reading this aware of what the truth really is?
>
> Dana
>
>
> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <
> mag...@rubidium.dyndns.org
> > wrote:
>
> >
> >
> > On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
> > >> --
> > >>
> > >> Message: 2
> > >> Date: Sat, 6 Jan 2018 09:19:31 -0500
> > >> From: Bob kb8tq <kb...@n1k.org>
> > >> To: Discussion of precise time and frequency measurement
> > >> <time-nuts@febo.com>
> > >> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> > >> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
> > >> Content-Type: text/plain; charset=utf-8
> > >>
> > >> Hi
> > >>
> > >> The key point missing is the fact that any real oscillator must have
> > >> a limiter
> > >> in the loop. Otherwise it will “create one” by going over the max
> > >> output of this or
> > >> that amplifier. To the degree that the limiter has issues (limits
> > >> poorly) you will get
> > >> AM noise.
> > >
> > > Hmm. Not strictly true. One can also use an AGC loop, like a wein
> > > bridge oscillator. That said, some kind of softish limiter is commonly
> > > used.
> >
> > Regardless what non-linear mechanism in play, this remains a non-linear
> > mechanism that achieves the goal. Choose wisely.
> >
> > Cheers,
> > Magnus
> > ___
> > time-nuts 

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

[donald collie]

Does any limiter, soft or hard, [and perhaps any nonlinearity  of power
term 3 or greater in the amplifier of an oscillator] cause the "baseband
1/f noise to translate up to the resonator frequency [a form of
crossmodulation]?. I wonder this because
phase noise vs freq plots look a bit like the 1/f plots of a resistor, or
active device, or power supply. Ceramic caps, and resonators [I`m thinking
of quartz crystals] don`t pass much DC, and as I understand it, 1/f noise
is associated with dc passing through resistors, or semiconductors. So the
best way to go might be to have a very linear amplifier, which exhibits
very low noise [perhaps 150dB below the operating level], with an AGC loop,
that sets the operating levela little below the level at which the amp
starts to clip - this could be done with a thermistor to avoid the AGC loop
altering the [optimised] operating conditions of the amp. Alternatively you
might be able to use a tetrode device like a dual gate MOSFET, and apply
the AGC to the second gate. Thus you could keep the extremely linear amp
extremely linear. [150dB below 1Volt RMS is 0.032uV RMS].
Cheers!Don
ZL4GX

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On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoo...@gmail.com> 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.
> Is anybody reading this aware of what the truth really is?
>
> Dana
>
>
> On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <
> mag...@rubidium.dyndns.org
> > wrote:
>
> >
> >
> > On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
> > >> --
> > >>
> > >> Message: 2
> > >> Date: Sat, 6 Jan 2018 09:19:31 -0500
> > >> From: Bob kb8tq <kb...@n1k.org>
> > >> To: Discussion of precise time and frequency measurement
> > >>  <time-nuts@febo.com>
> > >> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> > >> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
> > >> Content-Type: text/plain;charset=utf-8
> > >>
> > >> Hi
> > >>
> > >> The key point missing is the fact that any real oscillator must have
> > >> a limiter
> > >> in the loop. Otherwise it will “create one” by going over the max
> > >> output of this or
> > >> that amplifier. To the degree that the limiter has issues (limits
> > >> poorly) you will get
> > >> AM noise.
> > >
> > > Hmm.  Not strictly true.  One can also use an AGC loop, like a wein
> > > bridge oscillator.  That said, some kind of softish limiter is commonly
> > > used.
> >
> > Regardless what non-linear mechanism in play, this remains a non-linear
> > mechanism that achieves the goal. Choose wisely.
> >
> > Cheers,
> > Magnus
> > ___
> > 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.
> >
> ___
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> mailman/listinfo/time-nuts
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Re: [time-nuts] AM vs PM noise of signal sources

[Dana Whitlow]

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.
Is anybody reading this aware of what the truth really is?

Dana


On Sat, Jan 6, 2018 at 4:29 PM, Magnus Danielson <mag...@rubidium.dyndns.org
> wrote:

>
>
> On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
> >> --
> >>
> >> Message: 2
> >> Date: Sat, 6 Jan 2018 09:19:31 -0500
> >> From: Bob kb8tq <kb...@n1k.org>
> >> To: Discussion of precise time and frequency measurement
> >>  <time-nuts@febo.com>
> >> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> >> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
> >> Content-Type: text/plain;charset=utf-8
> >>
> >> Hi
> >>
> >> The key point missing is the fact that any real oscillator must have
> >> a limiter
> >> in the loop. Otherwise it will “create one” by going over the max
> >> output of this or
> >> that amplifier. To the degree that the limiter has issues (limits
> >> poorly) you will get
> >> AM noise.
> >
> > Hmm.  Not strictly true.  One can also use an AGC loop, like a wein
> > bridge oscillator.  That said, some kind of softish limiter is commonly
> > used.
>
> Regardless what non-linear mechanism in play, this remains a non-linear
> mechanism that achieves the goal. Choose wisely.
>
> Cheers,
> Magnus
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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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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

> On Jan 6, 2018, at 4:31 PM, Joseph Gwinn <joegw...@comcast.net> wrote:
> 
>> --
>> 
>> Message: 2
>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>> From: Bob kb8tq <kb...@n1k.org>
>> To: Discussion of precise time and frequency measurement
>>      <time-nuts@febo.com>
>> Subject: Re: [time-nuts] AM vs PM noise of signal sources
>> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
>> Content-Type: text/plain;charset=utf-8
>> 
>> Hi
>> 
>> The key point missing is the fact that any real oscillator must have 
>> a limiter
>> in the loop. Otherwise it will “create one” by going over the max 
>> output of this or
>> that amplifier. To the degree that the limiter has issues (limits 
>> poorly) you will get 
>> AM noise.
> 
> Hmm.  Not strictly true.  One can also use an AGC loop, like a wein 
> bridge oscillator.  That said, some kind of softish limiter is commonly 
> used.
> 
> Joe Gwinn 
> 

…. and a “soft” limiter (like an AGC)  likely will result in some very 
interesting noise showing up 
on the output.

Bob

> 
> 
>> On a practical basis, loop Q is as significant as resonator Q . The various 
>> elements in the loop degrade the total Q by a significant amount. 
>> Getting 25 to 
>> 50% of the resonator Q is “doing well” with his or that common 
>> circuit. Yes, there
>> are even more layers past this ….
>> 
>> Bob
>> 
>>> On Jan 6, 2018, at 1:53 AM, donald collie <donaldbcol...@gmail.com> wrote:
>>> 
>>> So to be lowest noise, an oscillator should have the highest Q resonator
>>> possible in its feedback loop, operate in class "A" [for maximum
>>> linearity], and utilise active amplifier device(s) that contribute the
>>> least noise [both amplitude, or 1/f], and phase. This latter implies
>>> operating the active device at maximum output level [ie signal to noise].
>>> The quality of the power supply effects the amplifier SNR, so in the
>>> persuit of superlative oscillator phase noise, the power supply should be
>>> as good as possible.
>>> Resistors in the oscillator carrying DC make 1/f noise - the best in this
>>> respect are the metal type, I think - so use metal resistors or WW.
>>> What are the other conciderations that come into the design, for lowest
>>> noise of the oscillator itself
>>> Split, then
>>> lump...;-).Cheers, de : Don
>>> ZL4GX
>>> 
> 
>> End of time-nuts Digest, Vol 162, Issue 10
>> **
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

….. except you can decide to use a “25%” design for your oscillator or you can 
go with a 
“50%” kind of circuit. It’s going to be a bit tough finding a crystal that is 
2X higher Q ….
Rick’s papers go through a bit of just *why* you would go with the “25%” 
circuit. 

Bob

> On Jan 6, 2018, at 9:25 AM, Magnus Danielson  
> wrote:
> 
> Hi,
> 
> I think loaded Q is being used as term these days for the effective Q of
> the resonator as loaded by the support amplifier.
> 
> The Leeson model only models how noise types gets created, not how a
> physical design actually works.
> 
> The modified Leeson model starts to approach the actual design.
> 
> Cheers,
> Magnus
> 
> On 01/06/2018 03:19 PM, Bob kb8tq wrote:
>> Hi
>> 
>> The key point missing is the fact that any real oscillator must have a 
>> limiter
>> in the loop. Otherwise it will “create one” by going over the max output of 
>> this or
>> that amplifier. To the degree that the limiter has issues (limits poorly) 
>> you will get 
>> AM noise.
>> 
>> On a practical basis, loop Q is as significant as resonator Q . The various 
>> elements in the loop degrade the total Q by a significant amount. Getting 25 
>> to 
>> 50% of the resonator Q is “doing well” with his or that common circuit. Yes, 
>> there
>> are even more layers past this ….
>> 
>> Bob
>> 
>>> On Jan 6, 2018, at 1:53 AM, donald collie  wrote:
>>> 
>>> So to be lowest noise, an oscillator should have the highest Q resonator
>>> possible in its feedback loop, operate in class "A" [for maximum
>>> linearity], and utilise active amplifier device(s) that contribute the
>>> least noise [both amplitude, or 1/f], and phase. This latter implies
>>> operating the active device at maximum output level [ie signal to noise].
>>> The quality of the power supply effects the amplifier SNR, so in the
>>> persuit of superlative oscillator phase noise, the power supply should be
>>> as good as possible.
>>> Resistors in the oscillator carrying DC make 1/f noise - the best in this
>>> respect are the metal type, I think - so use metal resistors or WW.
>>> What are the other conciderations that come into the design, for lowest
>>> noise of the oscillator itself
>>> Split, then
>>> lump...;-).Cheers, de : Don
>>> ZL4GX
>>> 
>>> 
>>> Virus-free.
>>> www.avg.com
>>> 
>>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>> 
>>> On Sat, Jan 6, 2018 at 1:08 PM, Magnus Danielson >> 
 Joseph,
 
 On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
> On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
>> Send time-nuts mailing list submissions to
 
>> If I pass both a sine wave tone and a pile of audio noise through a
>> perfectly
>> linear circuit, I get no AM or PM noise sidebands on the signal. The
>> only way
>> they combine is if the circuit is non-linear. There are a lot of ways
>> to model
>> this non-linearity. The “old school” approach is with a polynomial
>> function. That
>> dates back at least into the 1930’s. The textbooks I used learning it
>> in the 1970’s
>> were written in the 1950’s. There are *many* decades of papers on
>> this stuff.
>> 
>> Simple answer is that some types of non-linearity transfer AM others
>> transfer PM.
>> Some transfer both. In some cases the spectrum of the modulation is
>> preserved.
>> In some cases the spectrum is re-shaped by the modulation process. As
>> I recall
>> we spend a semester going over the basics of what does what.
>> 
>> These days, you have the wonders of non-linear circuit analysis. To
>> the degree
>> that your models are accurate and that the methods used work, I’m
>> sure it will
>> give you similar data compared to the “old school” stuff.
> 
> All the points about the need for linearity are correct.  The best
> point of access to the math of phase noise (both AM and PM) is
> modulation theory - phase noise is low-index modulation of the RF
> carrier signal.  Given the very low modulation index, only the first
> term of the approximating Bessel series is significant.  The difference
> between AM and PM is the relative phasing of the modulation sidebands.
> Additive npose has no such phase relationship.
 
 May I just follow up on the assumption there. The Bessel series is the
 theoretical for what goes on in PM and also helps to explain one
 particular error I have seen. For one oscillator with particular bad
 noise, a commercial instruments gave positive PM nummbers. Rather than
 measuring the power of the signal, it measured the power 

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

[Magnus Danielson]

On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
>> --
>>
>> Message: 2
>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>> From: Bob kb8tq <kb...@n1k.org>
>> To: Discussion of precise time and frequency measurement
>>  <time-nuts@febo.com>
>> Subject: Re: [time-nuts] AM vs PM noise of signal sources
>> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
>> Content-Type: text/plain;charset=utf-8
>>
>> Hi
>>
>> The key point missing is the fact that any real oscillator must have 
>> a limiter
>> in the loop. Otherwise it will “create one” by going over the max 
>> output of this or
>> that amplifier. To the degree that the limiter has issues (limits 
>> poorly) you will get 
>> AM noise.
> 
> Hmm.  Not strictly true.  One can also use an AGC loop, like a wein 
> bridge oscillator.  That said, some kind of softish limiter is commonly 
> used.

Regardless what non-linear mechanism in play, this remains a non-linear
mechanism that achieves the goal. Choose wisely.

Cheers,
Magnus
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Re: [time-nuts] AM vs PM noise of signal sources

[Magnus Danielson]

Hi Joe,

On 01/06/2018 10:26 PM, Joseph Gwinn wrote:
> On Fri, 05 Jan 2018 21:54:58 -0500, time-nuts-requ...@febo.com wrote:
>> May I just follow up on the assumption there. The Bessel series is the
>> theoretical [basis] for what goes on in PM and also helps to explain one
>> particular error I have seen. For one oscillator with particularly bad
>> noise, a commercial instruments gave positive PM numbers. Rather than
>> measuring the power of the signal, it measured the power of the carrier.
>> Under the assumption of low index modulation the Bessel for the carrier
>> is very close to 1, so it is fairly safe assumption. However, for higher
>> index the carrier suppresses, and that matches that the Bessel becomes
>> lower. That's what happened, so a read-out of the carrier is no longer
>> representing the power of the signal.
>>
>> However, if you do have low index modulation, you can assume the center
>> carrier to be as close to full power as you want, and the two
>> side-carriers has a very simple linear approximation.
> 
> 
> Yes.  This is exactly right.  There is a modulation index for which the 
> carrier is totally suppressed.  

Yes, the first of a series of zeros is at 2,4048.

> That must have been a very bad oscillator.

It was. None of mine, and not my measurement, I just helped triage it.

> You mentioned elsewhere that we now have to consider AM, not just PM.  
> This has been my experience as well, especially with power supply noise 
> fed to a final RF power amplifier, especially if that final amplifier 
> (or its driver) is not fully saturated.

Indeed, and the risk of AM-to-PM conversion makes huge difference in AM
and PM levels allow circuits to ruin the PM properties. If you consider
it as an act of isolation and the need for balance to ensure the
isolation, it becomes easier to understand conceptually.

Cheers,
Magnus
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Re: [time-nuts] AM vs PM noise of signal sources

[Joseph Gwinn]

> --
> 
> Message: 2
> Date: Sat, 6 Jan 2018 09:19:31 -0500
> From: Bob kb8tq <kb...@n1k.org>
> To: Discussion of precise time and frequency measurement
>   <time-nuts@febo.com>
> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> Message-ID: <ddef34dd-ad21-44c6-9612-d87788107...@n1k.org>
> Content-Type: text/plain; charset=utf-8
> 
> Hi
> 
> The key point missing is the fact that any real oscillator must have 
> a limiter
> in the loop. Otherwise it will “create one” by going over the max 
> output of this or
> that amplifier. To the degree that the limiter has issues (limits 
> poorly) you will get 
> AM noise.

Hmm.  Not strictly true.  One can also use an AGC loop, like a wein 
bridge oscillator.  That said, some kind of softish limiter is commonly 
used.

Joe Gwinn 



> On a practical basis, loop Q is as significant as resonator Q . The various 
> elements in the loop degrade the total Q by a significant amount. 
> Getting 25 to 
> 50% of the resonator Q is “doing well” with his or that common 
> circuit. Yes, there
> are even more layers past this ….
> 
> Bob
> 
>> On Jan 6, 2018, at 1:53 AM, donald collie <donaldbcol...@gmail.com> wrote:
>> 
>> So to be lowest noise, an oscillator should have the highest Q resonator
>> possible in its feedback loop, operate in class "A" [for maximum
>> linearity], and utilise active amplifier device(s) that contribute the
>> least noise [both amplitude, or 1/f], and phase. This latter implies
>> operating the active device at maximum output level [ie signal to noise].
>> The quality of the power supply effects the amplifier SNR, so in the
>> persuit of superlative oscillator phase noise, the power supply should be
>> as good as possible.
>> Resistors in the oscillator carrying DC make 1/f noise - the best in this
>> respect are the metal type, I think - so use metal resistors or WW.
>> What are the other conciderations that come into the design, for lowest
>> noise of the oscillator itself
>> Split, then
>> lump...;-).Cheers, de : Don
>> ZL4GX
>> 

> End of time-nuts Digest, Vol 162, Issue 10
> **
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Re: [time-nuts] AM vs PM noise of signal sources

[Joseph Gwinn]

On Fri, 05 Jan 2018 21:54:58 -0500, time-nuts-requ...@febo.com wrote:

> Message: 13
> Date: Sat, 6 Jan 2018 01:08:45 +0100
> From: Magnus Danielson <mag...@rubidium.dyndns.org>
> To: time-nuts@febo.com
> Cc: mag...@rubidium.se
> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> Message-ID: <d286e789-d466-ed27-d436-d2bdbdb30...@rubidium.dyndns.org>
> Content-Type: text/plain; charset=utf-8
> 
> Joseph,
> 
> On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
>> On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
>>> Send time-nuts mailing list submissions to
> 
>>> If I pass both a sine wave tone and a pile of audio noise through a 
>>> perfectly 
>>> linear circuit, I get no AM or PM noise sidebands on the signal. The 
>>> only way
>>> they combine is if the circuit is non-linear. There are a lot of ways 
>>> to model 
>>> this non-linearity. The “old school” approach is with a polynomial 
>>> function. That
>>> dates back at least into the 1930’s. The textbooks I used learning it 
>>> in the 1970’s 
>>> were written in the 1950’s. There are *many* decades of papers on 
>>> this stuff. 
>>> 
>>> Simple answer is that some types of non-linearity transfer AM others 
>>> transfer PM. 
>>> Some transfer both. In some cases the spectrum of the modulation is 
>>> preserved.
>>> In some cases the spectrum is re-shaped by the modulation process. As 
>>> I recall 
>>> we spend a semester going over the basics of what does what. 
>>> 
>>> These days, you have the wonders of non-linear circuit analysis. To 
>>> the degree 
>>> that your models are accurate and that the methods used work, I’m 
>>> sure it will 
>>> give you similar data compared to the “old school” stuff. 
>> 
>> All the points about the need for linearity are correct.  The best 
>> point of access to the math of phase noise (both AM and PM) is 
>> modulation theory - phase noise is low-index modulation of the RF 
>> carrier signal.  Given the very low modulation index, only the first 
>> term of the approximating Bessel series is significant.  The difference 
>> between AM and PM is the relative phasing of the modulation sidebands.  
>> Additive noise has no such phase relationship.
> 
> May I just follow up on the assumption there. The Bessel series is the
> theoretical [basis] for what goes on in PM and also helps to explain one
> particular error I have seen. For one oscillator with particularly bad
> noise, a commercial instruments gave positive PM numbers. Rather than
> measuring the power of the signal, it measured the power of the carrier.
> Under the assumption of low index modulation the Bessel for the carrier
> is very close to 1, so it is fairly safe assumption. However, for higher
> index the carrier suppresses, and that matches that the Bessel becomes
> lower. That's what happened, so a read-out of the carrier is no longer
> representing the power of the signal.
> 
> However, if you do have low index modulation, you can assume the center
> carrier to be as close to full power as you want, and the two
> side-carriers has a very simple linear approximation.


Yes.  This is exactly right.  There is a modulation index for which the 
carrier is totally suppressed.  

That must have been a very bad oscillator.

You mentioned elsewhere that we now have to consider AM, not just PM.  
This has been my experience as well, especially with power supply noise 
fed to a final RF power amplifier, especially if that final amplifier 
(or its driver) is not fully saturated.

Joe


> Cheers,
> Magnus

> End of time-nuts Digest, Vol 162, Issue 9
> *
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Re: [time-nuts] AM vs PM noise of signal sources

[Magnus Danielson]

Hi,

I think loaded Q is being used as term these days for the effective Q of
the resonator as loaded by the support amplifier.

The Leeson model only models how noise types gets created, not how a
physical design actually works.

The modified Leeson model starts to approach the actual design.

Cheers,
Magnus

On 01/06/2018 03:19 PM, Bob kb8tq wrote:
> Hi
> 
> The key point missing is the fact that any real oscillator must have a limiter
> in the loop. Otherwise it will “create one” by going over the max output of 
> this or
> that amplifier. To the degree that the limiter has issues (limits poorly) you 
> will get 
> AM noise.
> 
> On a practical basis, loop Q is as significant as resonator Q . The various 
> elements in the loop degrade the total Q by a significant amount. Getting 25 
> to 
> 50% of the resonator Q is “doing well” with his or that common circuit. Yes, 
> there
> are even more layers past this ….
> 
> Bob
> 
>> On Jan 6, 2018, at 1:53 AM, donald collie  wrote:
>>
>> So to be lowest noise, an oscillator should have the highest Q resonator
>> possible in its feedback loop, operate in class "A" [for maximum
>> linearity], and utilise active amplifier device(s) that contribute the
>> least noise [both amplitude, or 1/f], and phase. This latter implies
>> operating the active device at maximum output level [ie signal to noise].
>> The quality of the power supply effects the amplifier SNR, so in the
>> persuit of superlative oscillator phase noise, the power supply should be
>> as good as possible.
>> Resistors in the oscillator carrying DC make 1/f noise - the best in this
>> respect are the metal type, I think - so use metal resistors or WW.
>> What are the other conciderations that come into the design, for lowest
>> noise of the oscillator itself
>> Split, then
>> lump...;-).Cheers, de : Don
>> ZL4GX
>>
>> 
>> Virus-free.
>> www.avg.com
>> 
>> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>
>> On Sat, Jan 6, 2018 at 1:08 PM, Magnus Danielson >> wrote:
>>
>>> Joseph,
>>>
>>> On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
 On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
> Send time-nuts mailing list submissions to
>>>
> If I pass both a sine wave tone and a pile of audio noise through a
> perfectly
> linear circuit, I get no AM or PM noise sidebands on the signal. The
> only way
> they combine is if the circuit is non-linear. There are a lot of ways
> to model
> this non-linearity. The “old school” approach is with a polynomial
> function. That
> dates back at least into the 1930’s. The textbooks I used learning it
> in the 1970’s
> were written in the 1950’s. There are *many* decades of papers on
> this stuff.
>
> Simple answer is that some types of non-linearity transfer AM others
> transfer PM.
> Some transfer both. In some cases the spectrum of the modulation is
> preserved.
> In some cases the spectrum is re-shaped by the modulation process. As
> I recall
> we spend a semester going over the basics of what does what.
>
> These days, you have the wonders of non-linear circuit analysis. To
> the degree
> that your models are accurate and that the methods used work, I’m
> sure it will
> give you similar data compared to the “old school” stuff.

 All the points about the need for linearity are correct.  The best
 point of access to the math of phase noise (both AM and PM) is
 modulation theory - phase noise is low-index modulation of the RF
 carrier signal.  Given the very low modulation index, only the first
 term of the approximating Bessel series is significant.  The difference
 between AM and PM is the relative phasing of the modulation sidebands.
 Additive npose has no such phase relationship.
>>>
>>> May I just follow up on the assumption there. The Bessel series is the
>>> theoretical for what goes on in PM and also helps to explain one
>>> particular error I have seen. For one oscillator with particular bad
>>> noise, a commercial instruments gave positive PM nummbers. Rather than
>>> measuring the power of the signal, it measured the power of the carrier.
>>> Under the assumption of low index modulation the Bessel for the carrier
>>> is very close to 1, so it is fairly safe assumption. However, for higher
>>> index the carrier suppresses, and that matches that the Bessel becomes
>>> lower. That's what happen, so a read-out of the carrier is no longer
>>> representing the power of the signal.
>>>
>>> However, if you do have low index modulation, you can assume the center
>>> carrier to be as close to full power as you want, and the 

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

[Bob kb8tq]

Hi

The key point missing is the fact that any real oscillator must have a limiter
in the loop. Otherwise it will “create one” by going over the max output of 
this or
that amplifier. To the degree that the limiter has issues (limits poorly) you 
will get 
AM noise.

On a practical basis, loop Q is as significant as resonator Q . The various 
elements in the loop degrade the total Q by a significant amount. Getting 25 to 
50% of the resonator Q is “doing well” with his or that common circuit. Yes, 
there
are even more layers past this ….

Bob

> On Jan 6, 2018, at 1:53 AM, donald collie  wrote:
> 
> So to be lowest noise, an oscillator should have the highest Q resonator
> possible in its feedback loop, operate in class "A" [for maximum
> linearity], and utilise active amplifier device(s) that contribute the
> least noise [both amplitude, or 1/f], and phase. This latter implies
> operating the active device at maximum output level [ie signal to noise].
> The quality of the power supply effects the amplifier SNR, so in the
> persuit of superlative oscillator phase noise, the power supply should be
> as good as possible.
> Resistors in the oscillator carrying DC make 1/f noise - the best in this
> respect are the metal type, I think - so use metal resistors or WW.
> What are the other conciderations that come into the design, for lowest
> noise of the oscillator itself
> Split, then
> lump...;-).Cheers, de : Don
> ZL4GX
> 
> 
> Virus-free.
> www.avg.com
> 
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> 
> On Sat, Jan 6, 2018 at 1:08 PM, Magnus Danielson > wrote:
> 
>> Joseph,
>> 
>> On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
>>> On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
 Send time-nuts mailing list submissions to
>> 
 If I pass both a sine wave tone and a pile of audio noise through a
 perfectly
 linear circuit, I get no AM or PM noise sidebands on the signal. The
 only way
 they combine is if the circuit is non-linear. There are a lot of ways
 to model
 this non-linearity. The “old school” approach is with a polynomial
 function. That
 dates back at least into the 1930’s. The textbooks I used learning it
 in the 1970’s
 were written in the 1950’s. There are *many* decades of papers on
 this stuff.
 
 Simple answer is that some types of non-linearity transfer AM others
 transfer PM.
 Some transfer both. In some cases the spectrum of the modulation is
 preserved.
 In some cases the spectrum is re-shaped by the modulation process. As
 I recall
 we spend a semester going over the basics of what does what.
 
 These days, you have the wonders of non-linear circuit analysis. To
 the degree
 that your models are accurate and that the methods used work, I’m
 sure it will
 give you similar data compared to the “old school” stuff.
>>> 
>>> All the points about the need for linearity are correct.  The best
>>> point of access to the math of phase noise (both AM and PM) is
>>> modulation theory - phase noise is low-index modulation of the RF
>>> carrier signal.  Given the very low modulation index, only the first
>>> term of the approximating Bessel series is significant.  The difference
>>> between AM and PM is the relative phasing of the modulation sidebands.
>>> Additive npose has no such phase relationship.
>> 
>> May I just follow up on the assumption there. The Bessel series is the
>> theoretical for what goes on in PM and also helps to explain one
>> particular error I have seen. For one oscillator with particular bad
>> noise, a commercial instruments gave positive PM nummbers. Rather than
>> measuring the power of the signal, it measured the power of the carrier.
>> Under the assumption of low index modulation the Bessel for the carrier
>> is very close to 1, so it is fairly safe assumption. However, for higher
>> index the carrier suppresses, and that matches that the Bessel becomes
>> lower. That's what happen, so a read-out of the carrier is no longer
>> representing the power of the signal.
>> 
>> However, if you do have low index modulation, you can assume the center
>> carrier to be as close to full power as you want, and the two
>> side-carriers has a very simple linear approximation.
>> 
>> Cheers,
>> Magnus
>> ___
>> 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.
>> 
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Re: [time-nuts] AM vs PM noise of signal sources

[donald collie]

So to be lowest noise, an oscillator should have the highest Q resonator
possible in its feedback loop, operate in class "A" [for maximum
linearity], and utilise active amplifier device(s) that contribute the
least noise [both amplitude, or 1/f], and phase. This latter implies
operating the active device at maximum output level [ie signal to noise].
The quality of the power supply effects the amplifier SNR, so in the
persuit of superlative oscillator phase noise, the power supply should be
as good as possible.
Resistors in the oscillator carrying DC make 1/f noise - the best in this
respect are the metal type, I think - so use metal resistors or WW.
What are the other conciderations that come into the design, for lowest
noise of the oscillator itself
Split, then
lump...;-).Cheers, de : Don
ZL4GX


Virus-free.
www.avg.com

<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

On Sat, Jan 6, 2018 at 1:08 PM, Magnus Danielson  wrote:

> Joseph,
>
> On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
> > On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
> >> Send time-nuts mailing list submissions to
>
> >> If I pass both a sine wave tone and a pile of audio noise through a
> >> perfectly
> >> linear circuit, I get no AM or PM noise sidebands on the signal. The
> >> only way
> >> they combine is if the circuit is non-linear. There are a lot of ways
> >> to model
> >> this non-linearity. The “old school” approach is with a polynomial
> >> function. That
> >> dates back at least into the 1930’s. The textbooks I used learning it
> >> in the 1970’s
> >> were written in the 1950’s. There are *many* decades of papers on
> >> this stuff.
> >>
> >> Simple answer is that some types of non-linearity transfer AM others
> >> transfer PM.
> >> Some transfer both. In some cases the spectrum of the modulation is
> >> preserved.
> >> In some cases the spectrum is re-shaped by the modulation process. As
> >> I recall
> >> we spend a semester going over the basics of what does what.
> >>
> >> These days, you have the wonders of non-linear circuit analysis. To
> >> the degree
> >> that your models are accurate and that the methods used work, I’m
> >> sure it will
> >> give you similar data compared to the “old school” stuff.
> >
> > All the points about the need for linearity are correct.  The best
> > point of access to the math of phase noise (both AM and PM) is
> > modulation theory - phase noise is low-index modulation of the RF
> > carrier signal.  Given the very low modulation index, only the first
> > term of the approximating Bessel series is significant.  The difference
> > between AM and PM is the relative phasing of the modulation sidebands.
> > Additive npose has no such phase relationship.
>
> May I just follow up on the assumption there. The Bessel series is the
> theoretical for what goes on in PM and also helps to explain one
> particular error I have seen. For one oscillator with particular bad
> noise, a commercial instruments gave positive PM nummbers. Rather than
> measuring the power of the signal, it measured the power of the carrier.
> Under the assumption of low index modulation the Bessel for the carrier
> is very close to 1, so it is fairly safe assumption. However, for higher
> index the carrier suppresses, and that matches that the Bessel becomes
> lower. That's what happen, so a read-out of the carrier is no longer
> representing the power of the signal.
>
> However, if you do have low index modulation, you can assume the center
> carrier to be as close to full power as you want, and the two
> side-carriers has a very simple linear approximation.
>
> Cheers,
> Magnus
> ___
> 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.
>
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Re: [time-nuts] AM vs PM noise of signal sources

[Magnus Danielson]

Joseph,

On 01/05/2018 09:16 PM, Joseph Gwinn wrote:
> On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
>> Send time-nuts mailing list submissions to

>> If I pass both a sine wave tone and a pile of audio noise through a 
>> perfectly 
>> linear circuit, I get no AM or PM noise sidebands on the signal. The 
>> only way
>> they combine is if the circuit is non-linear. There are a lot of ways 
>> to model 
>> this non-linearity. The “old school” approach is with a polynomial 
>> function. That
>> dates back at least into the 1930’s. The textbooks I used learning it 
>> in the 1970’s 
>> were written in the 1950’s. There are *many* decades of papers on 
>> this stuff. 
>>
>> Simple answer is that some types of non-linearity transfer AM others 
>> transfer PM. 
>> Some transfer both. In some cases the spectrum of the modulation is 
>> preserved.
>> In some cases the spectrum is re-shaped by the modulation process. As 
>> I recall 
>> we spend a semester going over the basics of what does what. 
>>
>> These days, you have the wonders of non-linear circuit analysis. To 
>> the degree 
>> that your models are accurate and that the methods used work, I’m 
>> sure it will 
>> give you similar data compared to the “old school” stuff. 
> 
> All the points about the need for linearity are correct.  The best 
> point of access to the math of phase noise (both AM and PM) is 
> modulation theory - phase noise is low-index modulation of the RF 
> carrier signal.  Given the very low modulation index, only the first 
> term of the approximating Bessel series is significant.  The difference 
> between AM and PM is the relative phasing of the modulation sidebands.  
> Additive npose has no such phase relationship.

May I just follow up on the assumption there. The Bessel series is the
theoretical for what goes on in PM and also helps to explain one
particular error I have seen. For one oscillator with particular bad
noise, a commercial instruments gave positive PM nummbers. Rather than
measuring the power of the signal, it measured the power of the carrier.
Under the assumption of low index modulation the Bessel for the carrier
is very close to 1, so it is fairly safe assumption. However, for higher
index the carrier suppresses, and that matches that the Bessel becomes
lower. That's what happen, so a read-out of the carrier is no longer
representing the power of the signal.

However, if you do have low index modulation, you can assume the center
carrier to be as close to full power as you want, and the two
side-carriers has a very simple linear approximation.

Cheers,
Magnus
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Re: [time-nuts] AM vs PM noise of signal sources

[Magnus Danielson]

Hi Attila,

On 01/05/2018 12:27 PM, Attila Kinali wrote:
> On Tue, 2 Jan 2018 23:34:18 +0100
> Magnus Danielson  wrote:
> 
> [About AM noise being of equal power as PM noise]
> 
>> Now, for actual sources this is no longer true. The AM noise can be much
>> higher, which is why it can be a real danger to the PM noise if there is
>> a AM to PM noise conversion. One source of such conversion can be the
>> amplification stage, but another could be a mistuned filter, which have
>> different amplitudes of the side-bands, which can create conversion as
>> the balance does not balance the same way anymore.
> 
> Yes, exactly. I am currently trying to understand how noise affects
> circuits an how input and circuit noise get converted to output noise.
> First assumption that needs to be dropped is that the noise processes
> is purely additive and independent of the signal. This means that a
> noise process does not anymore produce equal AM and PM power.

I'd say that first assumption should be that you are not linear.
Still, linear systems can already do conversion of AM to/from PM. The
lack of balance keeps being ignored for so many cases.

Then with nonlinearity things intermodulate and you get all the fun you
want.

> I think I have a 90% solution of the noise processes and conversions
> in a sine-to-square converter (aka zero-crossing detector, aka comparator).
> But there is one process that keeps puzzling me. I think I know where in
> the circuit it must come from, but I have no explanation as to how it happens.

OK, let me see the notes on that...

Cheers,
Magnus
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

It can be either. The easy example is a tone that is outside the entire band of 
the noise. 
If it is a “real” noise spectrum, that’s never going to be the case. There will 
always be
*some* noise at the tone frequency in a real system. 

Bob

> On Jan 5, 2018, at 2:49 PM, Dana Whitlow  wrote:
> 
> But what I'm wondering, because this is important to the discussion, is the
> tone at a frequency encompassed on both sides by the noise band?  Or
> is the tone outside the noise band?
> 
> Dana
> 
> 
> On Fri, Jan 5, 2018 at 1:35 PM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> The audio (or RF) tone is summed with “baseband" noise. 1/F noise seems
>> to be the flavor of the day in recent postings. The only reason to use
>> audio
>> in the example is that it is really easy to demonstrate things at audio
>> with
>> a sound card.
>> 
>> Bob
>> 
>>> On Jan 5, 2018, at 1:42 PM, Dana Whitlow  wrote:
>>> 
>>> Is this an audio tone, summed with audio noise whose spectrum surrounds
>>> that of the tone?
>>> 
>>> Dana
>>> 
>>> 
>>> On Fri, Jan 5, 2018 at 9:56 AM, Bob kb8tq  wrote:
>>> 
 Hi
 
 If I pass both a sine wave tone and a pile of audio noise through a
 perfectly
 linear circuit, I get no AM or PM noise sidebands on the signal. The
>> only
 way
 they combine is if the circuit is non-linear. There are a lot of ways to
 model
 this non-linearity. The “old school” approach is with a polynomial
 function. That
 dates back at least into the 1930’s. The textbooks I used learning it in
 the 1970’s
 were written in the 1950’s. There are *many* decades of papers on this
 stuff.
 
 Simple answer is that some types of non-linearity transfer AM others
 transfer PM.
 Some transfer both. In some cases the spectrum of the modulation is
 preserved.
 In some cases the spectrum is re-shaped by the modulation process. As I
 recall
 we spend a semester going over the basics of what does what.
 
 These days, you have the wonders of non-linear circuit analysis. To the
 degree
 that your models are accurate and that the methods used work, I’m sure
>> it
 will
 give you similar data compared to the “old school” stuff.
 
 Bob
 
> On Jan 5, 2018, at 6:27 AM, Attila Kinali  wrote:
> 
> On Tue, 2 Jan 2018 23:34:18 +0100
> Magnus Danielson  wrote:
> 
> [About AM noise being of equal power as PM noise]
> 
>> Now, for actual sources this is no longer true. The AM noise can be
>> much
>> higher, which is why it can be a real danger to the PM noise if there
>> is
>> a AM to PM noise conversion. One source of such conversion can be the
>> amplification stage, but another could be a mistuned filter, which
>> have
>> different amplitudes of the side-bands, which can create conversion as
>> the balance does not balance the same way anymore.
> 
> Yes, exactly. I am currently trying to understand how noise affects
> circuits an how input and circuit noise get converted to output noise.
> First assumption that needs to be dropped is that the noise processes
> is purely additive and independent of the signal. This means that a
> noise process does not anymore produce equal AM and PM power.
> 
> I think I have a 90% solution of the noise processes and conversions
> in a sine-to-square converter (aka zero-crossing detector, aka
 comparator).
> But there is one process that keeps puzzling me. I think I know where
>> in
> the circuit it must come from, but I have no explanation as to how it
 happens.
> 
> 
> Attila Kinali
> --
> It is upon moral qualities that a society is ultimately founded. All
> the prosperity and technological sophistication in the world is of no
> use without that foundation.
>   -- Miss Matheson, The Diamond Age, Neil Stephenson
> ___
> 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.
 
 ___
 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.
 
>>> ___
>>> 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.
>> 
>> ___
>> 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 

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

[Joseph Gwinn]

On Fri, 05 Jan 2018 12:00:01 -0500, time-nuts-requ...@febo.com wrote:
> Send time-nuts mailing list submissions to
>   time-nuts@febo.com
> 
> To subscribe or unsubscribe via the World Wide Web, visit
>   https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> or, via email, send a message with subject or body 'help' to
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> 
> You can reach the person managing the list at
>   time-nuts-ow...@febo.com
> 
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of time-nuts digest..."
> 
> 
> Today's Topics:
> 
>1. Re: Stable32 now available (Graham)
>2. Re: Stable32 now available (Dr. David Kirkby)
>3. Re: AM vs PM noise of signal sources (Bob kb8tq)
>4. HP 105B: Modern replacement for NiCad battery pack?
>   (Ulf Kylenfall)
> 
> 
> --
> 
> --
> 
> Message: 3
> Date: Fri, 5 Jan 2018 10:56:17 -0500
> From: Bob kb8tq <kb...@n1k.org>
> To: Discussion of precise time and frequency measurement
>   <time-nuts@febo.com>
> Subject: Re: [time-nuts] AM vs PM noise of signal sources
> Message-ID: <f69f7893-ae69-4430-bafa-752746bd0...@n1k.org>
> Content-Type: text/plain; charset=utf-8
> 
> Hi
> 
> If I pass both a sine wave tone and a pile of audio noise through a 
> perfectly 
> linear circuit, I get no AM or PM noise sidebands on the signal. The 
> only way
> they combine is if the circuit is non-linear. There are a lot of ways 
> to model 
> this non-linearity. The “old school” approach is with a polynomial 
> function. That
> dates back at least into the 1930’s. The textbooks I used learning it 
> in the 1970’s 
> were written in the 1950’s. There are *many* decades of papers on 
> this stuff. 
> 
> Simple answer is that some types of non-linearity transfer AM others 
> transfer PM. 
> Some transfer both. In some cases the spectrum of the modulation is 
> preserved.
> In some cases the spectrum is re-shaped by the modulation process. As 
> I recall 
> we spend a semester going over the basics of what does what. 
> 
> These days, you have the wonders of non-linear circuit analysis. To 
> the degree 
> that your models are accurate and that the methods used work, I’m 
> sure it will 
> give you similar data compared to the “old school” stuff. 

All the points about the need for linearity are correct.  The best 
point of access to the math of phase noise (both AM and PM) is 
modulation theory - phase noise is low-index modulation of the RF 
carrier signal.  Given the very low modulation index, only the first 
term of the approximating Bessel series is significant.  The difference 
between AM and PM is the relative phasing of the modulation sidebands.  
Additive npose has no such phase relationship.

Joe Gwinn


> Bob
> 
>> On Jan 5, 2018, at 6:27 AM, Attila Kinali <att...@kinali.ch> wrote:
>> 
>> On Tue, 2 Jan 2018 23:34:18 +0100
>> Magnus Danielson <mag...@rubidium.dyndns.org> wrote:
>> 
>> [About AM noise being of equal power as PM noise]
>> 
>>> Now, for actual sources this is no longer true. The AM noise can be much
>>> higher, which is why it can be a real danger to the PM noise if there is
>>> a AM to PM noise conversion. One source of such conversion can be the
>>> amplification stage, but another could be a mistuned filter, which have
>>> different amplitudes of the side-bands, which can create conversion as
>>> the balance does not balance the same way anymore.
>> 
>> Yes, exactly. I am currently trying to understand how noise affects
>> circuits an how input and circuit noise get converted to output noise.
>> First assumption that needs to be dropped is that the noise processes
>> is purely additive and independent of the signal. This means that a
>> noise process does not anymore produce equal AM and PM power.
>> 
>> I think I have a 90% solution of the noise processes and conversions
>> in a sine-to-square converter (aka zero-crossing detector, aka comparator).
>> But there is one process that keeps puzzling me. I think I know where in
>> the circuit it must come from, but I have no explanation as to how 
>> it happens.
>> 
>> 
>>  Attila Kinali
>> -- 
>> It is upon moral qualities that a society is ultimately founded. All 
>> the prosperity and technological sophistication in the world is of no 
>> use without that foundation.
>> -- Miss Matheson, The Diamond Age, Neil Stephenson
>> ___
> 
> End of time-nuts Digest, Vol 162, Issue 7
> *
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Re: [time-nuts] AM vs PM noise of signal sources

[Dana Whitlow]

But what I'm wondering, because this is important to the discussion, is the
tone at a frequency encompassed on both sides by the noise band?  Or
is the tone outside the noise band?

Dana


On Fri, Jan 5, 2018 at 1:35 PM, Bob kb8tq  wrote:

> Hi
>
> The audio (or RF) tone is summed with “baseband" noise. 1/F noise seems
> to be the flavor of the day in recent postings. The only reason to use
> audio
> in the example is that it is really easy to demonstrate things at audio
> with
> a sound card.
>
> Bob
>
> > On Jan 5, 2018, at 1:42 PM, Dana Whitlow  wrote:
> >
> > Is this an audio tone, summed with audio noise whose spectrum surrounds
> > that of the tone?
> >
> > Dana
> >
> >
> > On Fri, Jan 5, 2018 at 9:56 AM, Bob kb8tq  wrote:
> >
> >> Hi
> >>
> >> If I pass both a sine wave tone and a pile of audio noise through a
> >> perfectly
> >> linear circuit, I get no AM or PM noise sidebands on the signal. The
> only
> >> way
> >> they combine is if the circuit is non-linear. There are a lot of ways to
> >> model
> >> this non-linearity. The “old school” approach is with a polynomial
> >> function. That
> >> dates back at least into the 1930’s. The textbooks I used learning it in
> >> the 1970’s
> >> were written in the 1950’s. There are *many* decades of papers on this
> >> stuff.
> >>
> >> Simple answer is that some types of non-linearity transfer AM others
> >> transfer PM.
> >> Some transfer both. In some cases the spectrum of the modulation is
> >> preserved.
> >> In some cases the spectrum is re-shaped by the modulation process. As I
> >> recall
> >> we spend a semester going over the basics of what does what.
> >>
> >> These days, you have the wonders of non-linear circuit analysis. To the
> >> degree
> >> that your models are accurate and that the methods used work, I’m sure
> it
> >> will
> >> give you similar data compared to the “old school” stuff.
> >>
> >> Bob
> >>
> >>> On Jan 5, 2018, at 6:27 AM, Attila Kinali  wrote:
> >>>
> >>> On Tue, 2 Jan 2018 23:34:18 +0100
> >>> Magnus Danielson  wrote:
> >>>
> >>> [About AM noise being of equal power as PM noise]
> >>>
>  Now, for actual sources this is no longer true. The AM noise can be
> much
>  higher, which is why it can be a real danger to the PM noise if there
> is
>  a AM to PM noise conversion. One source of such conversion can be the
>  amplification stage, but another could be a mistuned filter, which
> have
>  different amplitudes of the side-bands, which can create conversion as
>  the balance does not balance the same way anymore.
> >>>
> >>> Yes, exactly. I am currently trying to understand how noise affects
> >>> circuits an how input and circuit noise get converted to output noise.
> >>> First assumption that needs to be dropped is that the noise processes
> >>> is purely additive and independent of the signal. This means that a
> >>> noise process does not anymore produce equal AM and PM power.
> >>>
> >>> I think I have a 90% solution of the noise processes and conversions
> >>> in a sine-to-square converter (aka zero-crossing detector, aka
> >> comparator).
> >>> But there is one process that keeps puzzling me. I think I know where
> in
> >>> the circuit it must come from, but I have no explanation as to how it
> >> happens.
> >>>
> >>>
> >>>  Attila Kinali
> >>> --
> >>> It is upon moral qualities that a society is ultimately founded. All
> >>> the prosperity and technological sophistication in the world is of no
> >>> use without that foundation.
> >>>-- Miss Matheson, The Diamond Age, Neil Stephenson
> >>> ___
> >>> 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.
> >>
> >> ___
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> >> mailman/listinfo/time-nuts
> >> and follow the instructions there.
> >>
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> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

The audio (or RF) tone is summed with “baseband" noise. 1/F noise seems 
to be the flavor of the day in recent postings. The only reason to use audio 
in the example is that it is really easy to demonstrate things at audio with 
a sound card. 

Bob

> On Jan 5, 2018, at 1:42 PM, Dana Whitlow  wrote:
> 
> Is this an audio tone, summed with audio noise whose spectrum surrounds
> that of the tone?
> 
> Dana
> 
> 
> On Fri, Jan 5, 2018 at 9:56 AM, Bob kb8tq  wrote:
> 
>> Hi
>> 
>> If I pass both a sine wave tone and a pile of audio noise through a
>> perfectly
>> linear circuit, I get no AM or PM noise sidebands on the signal. The only
>> way
>> they combine is if the circuit is non-linear. There are a lot of ways to
>> model
>> this non-linearity. The “old school” approach is with a polynomial
>> function. That
>> dates back at least into the 1930’s. The textbooks I used learning it in
>> the 1970’s
>> were written in the 1950’s. There are *many* decades of papers on this
>> stuff.
>> 
>> Simple answer is that some types of non-linearity transfer AM others
>> transfer PM.
>> Some transfer both. In some cases the spectrum of the modulation is
>> preserved.
>> In some cases the spectrum is re-shaped by the modulation process. As I
>> recall
>> we spend a semester going over the basics of what does what.
>> 
>> These days, you have the wonders of non-linear circuit analysis. To the
>> degree
>> that your models are accurate and that the methods used work, I’m sure it
>> will
>> give you similar data compared to the “old school” stuff.
>> 
>> Bob
>> 
>>> On Jan 5, 2018, at 6:27 AM, Attila Kinali  wrote:
>>> 
>>> On Tue, 2 Jan 2018 23:34:18 +0100
>>> Magnus Danielson  wrote:
>>> 
>>> [About AM noise being of equal power as PM noise]
>>> 
 Now, for actual sources this is no longer true. The AM noise can be much
 higher, which is why it can be a real danger to the PM noise if there is
 a AM to PM noise conversion. One source of such conversion can be the
 amplification stage, but another could be a mistuned filter, which have
 different amplitudes of the side-bands, which can create conversion as
 the balance does not balance the same way anymore.
>>> 
>>> Yes, exactly. I am currently trying to understand how noise affects
>>> circuits an how input and circuit noise get converted to output noise.
>>> First assumption that needs to be dropped is that the noise processes
>>> is purely additive and independent of the signal. This means that a
>>> noise process does not anymore produce equal AM and PM power.
>>> 
>>> I think I have a 90% solution of the noise processes and conversions
>>> in a sine-to-square converter (aka zero-crossing detector, aka
>> comparator).
>>> But there is one process that keeps puzzling me. I think I know where in
>>> the circuit it must come from, but I have no explanation as to how it
>> happens.
>>> 
>>> 
>>>  Attila Kinali
>>> --
>>> It is upon moral qualities that a society is ultimately founded. All
>>> the prosperity and technological sophistication in the world is of no
>>> use without that foundation.
>>>-- Miss Matheson, The Diamond Age, Neil Stephenson
>>> ___
>>> 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.
>> 
>> ___
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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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Re: [time-nuts] AM vs PM noise of signal sources

[Dana Whitlow]

Is this an audio tone, summed with audio noise whose spectrum surrounds
that of the tone?

Dana


On Fri, Jan 5, 2018 at 9:56 AM, Bob kb8tq  wrote:

> Hi
>
> If I pass both a sine wave tone and a pile of audio noise through a
> perfectly
> linear circuit, I get no AM or PM noise sidebands on the signal. The only
> way
> they combine is if the circuit is non-linear. There are a lot of ways to
> model
> this non-linearity. The “old school” approach is with a polynomial
> function. That
> dates back at least into the 1930’s. The textbooks I used learning it in
> the 1970’s
> were written in the 1950’s. There are *many* decades of papers on this
> stuff.
>
> Simple answer is that some types of non-linearity transfer AM others
> transfer PM.
> Some transfer both. In some cases the spectrum of the modulation is
> preserved.
> In some cases the spectrum is re-shaped by the modulation process. As I
> recall
> we spend a semester going over the basics of what does what.
>
> These days, you have the wonders of non-linear circuit analysis. To the
> degree
> that your models are accurate and that the methods used work, I’m sure it
> will
> give you similar data compared to the “old school” stuff.
>
> Bob
>
> > On Jan 5, 2018, at 6:27 AM, Attila Kinali  wrote:
> >
> > On Tue, 2 Jan 2018 23:34:18 +0100
> > Magnus Danielson  wrote:
> >
> > [About AM noise being of equal power as PM noise]
> >
> >> Now, for actual sources this is no longer true. The AM noise can be much
> >> higher, which is why it can be a real danger to the PM noise if there is
> >> a AM to PM noise conversion. One source of such conversion can be the
> >> amplification stage, but another could be a mistuned filter, which have
> >> different amplitudes of the side-bands, which can create conversion as
> >> the balance does not balance the same way anymore.
> >
> > Yes, exactly. I am currently trying to understand how noise affects
> > circuits an how input and circuit noise get converted to output noise.
> > First assumption that needs to be dropped is that the noise processes
> > is purely additive and independent of the signal. This means that a
> > noise process does not anymore produce equal AM and PM power.
> >
> > I think I have a 90% solution of the noise processes and conversions
> > in a sine-to-square converter (aka zero-crossing detector, aka
> comparator).
> > But there is one process that keeps puzzling me. I think I know where in
> > the circuit it must come from, but I have no explanation as to how it
> happens.
> >
> >
> >   Attila Kinali
> > --
> > It is upon moral qualities that a society is ultimately founded. All
> > the prosperity and technological sophistication in the world is of no
> > use without that foundation.
> > -- Miss Matheson, The Diamond Age, Neil Stephenson
> > ___
> > 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.
>
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

If I pass both a sine wave tone and a pile of audio noise through a perfectly 
linear circuit, I get no AM or PM noise sidebands on the signal. The only way
they combine is if the circuit is non-linear. There are a lot of ways to model 
this non-linearity. The “old school” approach is with a polynomial function. 
That
dates back at least into the 1930’s. The textbooks I used learning it in the 
1970’s 
were written in the 1950’s. There are *many* decades of papers on this stuff. 

Simple answer is that some types of non-linearity transfer AM others transfer 
PM. 
Some transfer both. In some cases the spectrum of the modulation is preserved.
In some cases the spectrum is re-shaped by the modulation process. As I recall 
we spend a semester going over the basics of what does what. 

These days, you have the wonders of non-linear circuit analysis. To the degree 
that your models are accurate and that the methods used work, I’m sure it will 
give you similar data compared to the “old school” stuff. 

Bob

> On Jan 5, 2018, at 6:27 AM, Attila Kinali  wrote:
> 
> On Tue, 2 Jan 2018 23:34:18 +0100
> Magnus Danielson  wrote:
> 
> [About AM noise being of equal power as PM noise]
> 
>> Now, for actual sources this is no longer true. The AM noise can be much
>> higher, which is why it can be a real danger to the PM noise if there is
>> a AM to PM noise conversion. One source of such conversion can be the
>> amplification stage, but another could be a mistuned filter, which have
>> different amplitudes of the side-bands, which can create conversion as
>> the balance does not balance the same way anymore.
> 
> Yes, exactly. I am currently trying to understand how noise affects
> circuits an how input and circuit noise get converted to output noise.
> First assumption that needs to be dropped is that the noise processes
> is purely additive and independent of the signal. This means that a
> noise process does not anymore produce equal AM and PM power.
> 
> I think I have a 90% solution of the noise processes and conversions
> in a sine-to-square converter (aka zero-crossing detector, aka comparator).
> But there is one process that keeps puzzling me. I think I know where in
> the circuit it must come from, but I have no explanation as to how it happens.
> 
> 
>   Attila Kinali
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
> ___
> 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.

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

[Attila Kinali]

On Tue, 2 Jan 2018 23:34:18 +0100
Magnus Danielson  wrote:

[About AM noise being of equal power as PM noise]

> Now, for actual sources this is no longer true. The AM noise can be much
> higher, which is why it can be a real danger to the PM noise if there is
> a AM to PM noise conversion. One source of such conversion can be the
> amplification stage, but another could be a mistuned filter, which have
> different amplitudes of the side-bands, which can create conversion as
> the balance does not balance the same way anymore.

Yes, exactly. I am currently trying to understand how noise affects
circuits an how input and circuit noise get converted to output noise.
First assumption that needs to be dropped is that the noise processes
is purely additive and independent of the signal. This means that a
noise process does not anymore produce equal AM and PM power.

I think I have a 90% solution of the noise processes and conversions
in a sine-to-square converter (aka zero-crossing detector, aka comparator).
But there is one process that keeps puzzling me. I think I know where in
the circuit it must come from, but I have no explanation as to how it happens.


Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] AM vs PM noise of signal sources

[Magnus Danielson]

Attila,

Since we talk background noise and white noise, the amplitude is the
same for AM and PM. This is part of the AM/PM lecture of NIST that I
know you have participated in at least once.

Under the assumption of low modulation index, which is fair assumption
for background noise compared to most carriers, both the AM and PM noise
of a certain side-offset has two side-band peaks, a lower and an upper.
The big difference is that for AM they have the same polarity and for PM
they have opposite polarity. Thus, they are as orthogonal as common mode
and differential mode. Noise on both absolute frequencies will combine
and contribute to the same AM and PM levels. It's that simple.

So, for that scenario you know one you know the other.

Now, for actual sources this is no longer true. The AM noise can be much
higher, which is why it can be a real danger to the PM noise if there is
a AM to PM noise conversion. One source of such conversion can be the
amplification stage, but another could be a mistuned filter, which have
different amplitudes of the side-bands, which can create conversion as
the balance does not balance the same way anymore.

Also turns out that the nitty-gritty of cross-correlation spectrum
analysis also occurs in AM-to-PM conversion and cancellation. This I had
not paid full attention to, but got reminded off at the workshop. Thus,
they are tied together and should be measured and understood together.

Cheers,
Magnus


On 01/02/2018 08:55 PM, Attila Kinali wrote:
> Hi,
> 
> I am currently looking at noise calculations that deal with AM and PM noise.
> To check whether the calculations make sense, I am looking for some numbers
> of the white noise floor AM and PM noise levels of signal sources.
> Unfortunately, almost everyone only deals with PM noise and hardly
> anyone mentiones AM noise levels. The best I could find sofar is [1]
> which supports the notion that AM noise is so far below PM noise, that
> it is insignificant. Does someone else have more data and would be willing
> to share?
> 
>   Attila Kinali
> 
> 
> [1] http://www.wenzel.com/documents/amnoise.htm
> 
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Re: [time-nuts] AM vs PM noise of signal sources

[Bob kb8tq]

Hi

Just as with PM noise, AM noise is a “that depends” sort of thing. The first 
dependency is on your test gear. If the AM noise was well below the PM 
noise, would you be able to measure it? Equally, if you are doing something 
like a diode detector - can it measure AM below XXX dbc? If the detector is
only good to -120 dbc/Hz, you aren’t going to “see” -130 ….

Noise on output state supply lines can generate AM. In some cases the stage
is a better AM modulator than PM modulator. Limiting (like with a logic gate) 
is not going to pass AM noise well.  That combination can make for some 
“interesting” noise profiles. 

One “old time” assumption for wide band noise is that there is no process that
will generate AM independent of PM. Thus they will always be in an equal power
relationship. The key phrase here is wide band. Think in terms of notching out 
the
carrier and looking at the result on a spectrum analyzer in this case. 

One of the classic arguments for an AGC or for certain types of limiters in
oscillators is AM to PM conversion. The concern here is “close to carrier” 
rather than far removed. There certainly are examples tossed around where
AM noise is significantly higher than PM noise at low offsets. 

So, no data that I can share. Maybe a few things in there will be of help.

Bob



> On Jan 2, 2018, at 2:55 PM, Attila Kinali  wrote:
> 
> Hi,
> 
> I am currently looking at noise calculations that deal with AM and PM noise.
> To check whether the calculations make sense, I am looking for some numbers
> of the white noise floor AM and PM noise levels of signal sources.
> Unfortunately, almost everyone only deals with PM noise and hardly
> anyone mentiones AM noise levels. The best I could find sofar is [1]
> which supports the notion that AM noise is so far below PM noise, that
> it is insignificant. Does someone else have more data and would be willing
> to share?
> 
>   Attila Kinali
> 
> 
> [1] http://www.wenzel.com/documents/amnoise.htm
> 
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
> ___
> 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.

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

[Attila Kinali]

Hi,

I am currently looking at noise calculations that deal with AM and PM noise.
To check whether the calculations make sense, I am looking for some numbers
of the white noise floor AM and PM noise levels of signal sources.
Unfortunately, almost everyone only deals with PM noise and hardly
anyone mentiones AM noise levels. The best I could find sofar is [1]
which supports the notion that AM noise is so far below PM noise, that
it is insignificant. Does someone else have more data and would be willing
to share?

Attila Kinali


[1] http://www.wenzel.com/documents/amnoise.htm

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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