JG
Joseph Gwinn
Sat, Jan 6, 2018 9:31 PM
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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 donaldbcollie@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
> ------------------------------
>
> Message: 2
> Date: Sat, 6 Jan 2018 09:19:31 -0500
> From: Bob kb8tq <kb8tq@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-D877881078E5@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 <donaldbcollie@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
> ******************************************
MD
Magnus Danielson
Sat, Jan 6, 2018 10:29 PM
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>> From: Bob kb8tq <kb8tq@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-D877881078E5@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
DW
Dana Whitlow
Sun, Jan 7, 2018 2:12 AM
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 <magnus@rubidium.dyndns.org
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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.
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 <magnus@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 <kb8tq@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-D877881078E5@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.
>
BK
Bob kb8tq
Sun, Jan 7, 2018 3:05 AM
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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 donaldbcollie@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
Hi
> On Jan 6, 2018, at 4:31 PM, Joseph Gwinn <joegwinn@comcast.net> wrote:
>
>> ------------------------------
>>
>> Message: 2
>> Date: Sat, 6 Jan 2018 09:19:31 -0500
>> From: Bob kb8tq <kb8tq@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-D877881078E5@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 <donaldbcollie@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
>> ******************************************
> _______________________________________________
> 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.
DC
donald collie
Sun, Jan 7, 2018 12:02 PM
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 [Im thinking of quartz crystals] dont 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 k8yumdoober@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 <
magnus@rubidium.dyndns.org
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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.
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&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
Virus-free.
www.avg.com
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoober@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 <
> magnus@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 <kb8tq@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-D877881078E5@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.
> >
> _______________________________________________
> 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.
>
UR
Ulrich Rohde
Sun, Jan 7, 2018 1:02 PM
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, donaldbcollie@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 [Im thinking of quartz crystals] dont 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&utm_source=link&utm_campaign=sig-email&utm_content=webmail
Virus-free.
www.avg.com
http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow k8yumdoober@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 <
magnus@rubidium.dyndns.org
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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.
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, donaldbcollie@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&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
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<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoober@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 <
> magnus@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 <kb8tq@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-D877881078E5@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.
> >
> _______________________________________________
> 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.
BK
Bob kb8tq
Sun, Jan 7, 2018 2:57 PM
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, donaldbcollie@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 [Im thinking of quartz crystals] dont 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&utm_source=link&utm_campaign=sig-email&utm_content=webmail
Virus-free.
www.avg.com
http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail
<#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow k8yumdoober@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 <
magnus@rubidium.dyndns.org
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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.
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, donaldbcollie@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&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> Virus-free.
> www.avg.com
> <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> On Sun, Jan 7, 2018 at 3:12 PM, Dana Whitlow <k8yumdoober@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 <
>> magnus@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 <kb8tq@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-D877881078E5@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.
>>>
>> _______________________________________________
>> 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.
BK
Bob kb8tq
Sun, Jan 7, 2018 3:08 PM
On Jan 6, 2018, at 9:12 PM, Dana Whitlow k8yumdoober@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
On 01/06/2018 10:31 PM, Joseph Gwinn wrote:
Message: 2
Date: Sat, 6 Jan 2018 09:19:31 -0500
From: Bob kb8tq kb8tq@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-D877881078E5@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.
Hi
> On Jan 6, 2018, at 9:12 PM, Dana Whitlow <k8yumdoober@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 <magnus@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 <kb8tq@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-D877881078E5@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.
>>
> _______________________________________________
> 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.
J
jimlux
Sun, Jan 7, 2018 3:33 PM
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.
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.
AT
Arnold Tibus
Sun, Jan 7, 2018 4:05 PM
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.
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
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
