strange oscillator...

[bitrex]

On 2/1/2022 12:59 PM, jlarkin@highlandsniptechnology.com wrote:

On Tue, 1 Feb 2022 12:05:49 -0500, bitrex <user@example.net> wrote:

On 2/1/2022 11:07 AM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 10:59:09 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

piglet wrote:
On 01/02/2022 3:27 pm, jlarkin@highlandsniptechnology.com wrote:
Not actually a Hartley, bacause the Ls are not coupled.



Yes, decades ago I built something similar using an NPN BJT at kHz
frequencies. I used two molded chokes and had initially them loose
coupled but was amazed that I could separate them or re-orient so there
was no mutual couplling and still got oscillation.

I think Irving Gottlieb described three types of Hartley in his
Oscillator Handbook and this is one of his \"type 2\" Hartleys, there is
no mutual coupling and the action is negative resistance.

piglet


With no coupling, it\'s a species of Colpitts--it\'s only the tank Q that
does the impedance transformation, with no help from the transformer
action of the mutual inductance.

Cheers

Phil Hobbs

I was just fooling around. What I really want is a 1.5 GHz oscillator
with two antiphase outputs. A MMIC might be a good gain element.

What about cross-coupled ECL-type oscillator

I could persuade a diff-in-out ecl gate or comparator to oscillate,
but I\'d have to try it. I don\'t have Spice models for those.

I might get lucky and just connect a diff gate into itself, inverted.
and watch it oscillate. Hey good idea! Might be fun to try.

A MMIC is a great gain element, but it\'s basically 50 ohms in and out,
the ideal tank Q killer. The best MMIC ocillator is probably
delay-line, which will give me antiphase outputs. Again, gotta solder
to test that.

If I recall there\'s a way to get a lil chain of D-type flip-flops to
self-oscillate, functioning as a self-oscillating ring counter/delay
line, but I\'m not sure there\'s any e.g. TinyLogic-type parts that can be
coaxed to 1+ GHz, as the minimum propagation time I think tends to be 2-3 ns

> I wish ADI would include their ADCMP parts in LT Spice.

 

[Lasse Langwadt Christensen]

onsdag den 2. februar 2022 kl. 16.45.55 UTC+1 skrev bitrex:

On 2/1/2022 12:59 PM, jla...@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 12:05:49 -0500, bitrex <us...@example.net> wrote:

On 2/1/2022 11:07 AM, jla...@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 10:59:09 -0500, Phil Hobbs
pcdhSpamM...@electrooptical.net> wrote:

piglet wrote:
On 01/02/2022 3:27 pm, jla...@highlandsniptechnology.com wrote:
Not actually a Hartley, bacause the Ls are not coupled.



Yes, decades ago I built something similar using an NPN BJT at kHz
frequencies. I used two molded chokes and had initially them loose
coupled but was amazed that I could separate them or re-orient so there
was no mutual couplling and still got oscillation.

I think Irving Gottlieb described three types of Hartley in his
Oscillator Handbook and this is one of his \"type 2\" Hartleys, there is
no mutual coupling and the action is negative resistance.

piglet


With no coupling, it\'s a species of Colpitts--it\'s only the tank Q that
does the impedance transformation, with no help from the transformer
action of the mutual inductance.

Cheers

Phil Hobbs

I was just fooling around. What I really want is a 1.5 GHz oscillator
with two antiphase outputs. A MMIC might be a good gain element.

What about cross-coupled ECL-type oscillator

I could persuade a diff-in-out ecl gate or comparator to oscillate,
but I\'d have to try it. I don\'t have Spice models for those.

I might get lucky and just connect a diff gate into itself, inverted.
and watch it oscillate. Hey good idea! Might be fun to try.

A MMIC is a great gain element, but it\'s basically 50 ohms in and out,
the ideal tank Q killer. The best MMIC ocillator is probably
delay-line, which will give me antiphase outputs. Again, gotta solder
to test that.
If I recall there\'s a way to get a lil chain of D-type flip-flops to
self-oscillate, functioning as a self-oscillating ring counter/delay
line, but I\'m not sure there\'s any e.g. TinyLogic-type parts that can be
coaxed to 1+ GHz, as the minimum propagation time I think tends to be 2-3 ns

https://hackaday.io/project/28833-microhacks/log/157535-just-how-fast-are-74auc-gates

 

[server]

On Wed, 2 Feb 2022 10:45:42 -0500, bitrex <user@example.net> wrote:

On 2/1/2022 12:59 PM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 12:05:49 -0500, bitrex <user@example.net> wrote:

On 2/1/2022 11:07 AM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 1 Feb 2022 10:59:09 -0500, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

piglet wrote:
On 01/02/2022 3:27 pm, jlarkin@highlandsniptechnology.com wrote:
Not actually a Hartley, bacause the Ls are not coupled.



Yes, decades ago I built something similar using an NPN BJT at kHz
frequencies. I used two molded chokes and had initially them loose
coupled but was amazed that I could separate them or re-orient so there
was no mutual couplling and still got oscillation.

I think Irving Gottlieb described three types of Hartley in his
Oscillator Handbook and this is one of his \"type 2\" Hartleys, there is
no mutual coupling and the action is negative resistance.

piglet


With no coupling, it\'s a species of Colpitts--it\'s only the tank Q that
does the impedance transformation, with no help from the transformer
action of the mutual inductance.

Cheers

Phil Hobbs

I was just fooling around. What I really want is a 1.5 GHz oscillator
with two antiphase outputs. A MMIC might be a good gain element.

What about cross-coupled ECL-type oscillator

I could persuade a diff-in-out ecl gate or comparator to oscillate,
but I\'d have to try it. I don\'t have Spice models for those.

I might get lucky and just connect a diff gate into itself, inverted.
and watch it oscillate. Hey good idea! Might be fun to try.

A MMIC is a great gain element, but it\'s basically 50 ohms in and out,
the ideal tank Q killer. The best MMIC ocillator is probably
delay-line, which will give me antiphase outputs. Again, gotta solder
to test that.

If I recall there\'s a way to get a lil chain of D-type flip-flops to
self-oscillate, functioning as a self-oscillating ring counter/delay
line, but I\'m not sure there\'s any e.g. TinyLogic-type parts that can be
coaxed to 1+ GHz, as the minimum propagation time I think tends to be 2-3 ns

We use Eclips Lite gates, 3 GHz stuff, and the fast ADCMP series
comparators. Even a few GigaComm parts, roughly 7 GHz.

There is some really fast logic around, ballpark 10 ps, but it\'s like
hundreds of dollars per gate.



--

I yam what I yam - Popeye

 

[Arnie Dwyer]

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.

[...]

Without doubt, the worst oscillator I have ever seen anyone design. You
are right. You are not an analog guy.

What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.

You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.

Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.

Instant hostility to idiotic ideas is easy. Did you know you tried to make
an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice to
be an insult and you ignore it. The resulting Q is
20.42/1e-3 = 20,420

Where do you plan of getting inductors like that?

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

Again, you completely ignore helpful advice that could teach you how to go
about designing a useful oscillator. The link I provided was a complete
waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

I defy you to make a useful oscillator by ignoring these rules.

 

[Jeroen Belleman]

Arnie Dwyer wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.
[...]

Without doubt, the worst oscillator I have ever seen anyone design. You
are right. You are not an analog guy.
What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.
You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.
Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.

Instant hostility to idiotic ideas is easy. Did you know you tried to make
an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice to
be an insult and you ignore it. The resulting Q is
20.42/1e-3 = 20,420

Where do you plan of getting inductors like that?

Don\'t be silly. What matters is the loaded Q. And this oscillator
will run just fine even with an effective Q below 10. The bare
coil Q is mostly irrelevant.

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

Many oscillator designs let the transistor current hit zero in order
to limit the amplitude. Inevitably, the signal at the source ends up
looking nasty, at least in the simulation. In a real circuit, it won\'t
look nearly as bad. If you need a purer output, you can always take it
from the top of the tank.

Jeroen Belleman

 

[Anthony William Sloman]

On Thursday, February 3, 2022 at 10:40:25 PM UTC+11, Arnie Dwyer wrote:

jla...@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spa...@not.com
wrote:

jla...@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spa...@not.com
wrote:

jla...@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.

[...]

Without doubt, the worst oscillator I have ever seen anyone design. You
are right. You are not an analog guy.

What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.

You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.

Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.
Instant hostility to idiotic ideas is easy. Did you know you tried to make
an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice to
be an insult and you ignore it. The resulting Q is
20.42/1e-3 = 20,420

Where do you plan on getting inductors like that?

He doesn\'t like thinking about inductors - too complicated - and buys them off the shelf when he has to use them.

The business of designing a special purpose transformer and getting it wound strikes him as more trouble than it can possibly be worth (though he has wound a special purpose inductor around a pencil and made a lot of fuss about the result.)

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

Again, you completely ignore helpful advice that could teach you how to go
about designing a useful oscillator.

He\'s here to garner flattery, not to listen to advice, nor humiliate himself by admitting that it was useful.

The link I provided was a complete
waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

Your first inductor doesn\'t have any parallel capacitance which isn\'t all that physically realistic either.

> I defy you to make a useful oscillator by ignoring these rules.

John Larkin\'s approach to design looks like evolution in action. He does seem to come up with useful - or least marketable - circuits, but if there is a design element in the development process he doesn\'t seem to be willing to talk about it.

--
Bill Sloman, Sydney

 

[John Larkin]

On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spamme@not.com>
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.

[...]

Without doubt, the worst oscillator I have ever seen anyone design. You
are right. You are not an analog guy.

What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.

You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.

Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.

Instant hostility to idiotic ideas is easy. Did you know you tried to make
an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice to
be an insult and you ignore it. The resulting Q is
20.42/1e-3 = 20,420

I don\'t consider your advice to be an insult. But real inductor Qs are
high enough that I can ignore them here; the phemt has gobs of gain.
The first step of circuit design is topology.

Where do you plan of getting inductors like that?

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

I doubt we\'d see those squiggles in real life. But we don\'t truly
trust Spice models for things like this; As Mike say, Spice is for
training your instincts. After futzing with a lot of sims, we pick the
best ones and build them.

Again, you completely ignore helpful advice that could teach you how to go
about designing a useful oscillator. The link I provided was a complete
waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

I defy you to make a useful oscillator by ignoring these rules.

I sell lots of products with oscillators. They always work. About the
only rule I respect is Conservation of Energy. This biz is full of
\"Rules\" that are wrong.


--

John Larkin Highland Technology, Inc trk

The cork popped merrily, and Lord Peter rose to his feet.
\"Bunter\", he said, \"I give you a toast. The triumph of Instinct over Reason\"

 

[Anthony William Sloman]

On Friday, February 4, 2022 at 1:20:06 AM UTC+11, John Larkin wrote:

On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:
On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:
On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:

I doubt we\'d see those squiggles in real life. But we don\'t truly
trust Spice models for things like this; As Mike say, Spice is for
training your instincts.

Of course you aren\'t all that picky about modelling your components carefully either.

> After futzing with a lot of sims, we pick the best ones and build them.

A sim that has an inductor without any parallel capacitance may look better than one with a more realistic inductor.

Again, you completely ignore helpful advice that could teach you how to go
about designing a useful oscillator. The link I provided was a complete
waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

I defy you to make a useful oscillator by ignoring these rules.

I sell lots of products with oscillators. They always work. About the only rule I respect is Conservation of Energy. This biz is full of \"Rules\" that are wrong.

If you understood the rules better, they\'d look wrong a lot less often.

--
Bill Sloman, Sydney

 

[Arnie Dwyer]

John Larkin <jjlarkin@highlandtechnology.com> wrote:

On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer
spamme@not.com> wrote:

jlarkin@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.

[...]

Without doubt, the worst oscillator I have ever seen anyone design.
You are right. You are not an analog guy.

What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.

You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.

Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.

Instant hostility to idiotic ideas is easy. Did you know you tried to
make an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice
to be an insult and you ignore it. The resulting Q is 20.42/1e-3 =
20,420

I don\'t consider your advice to be an insult. But real inductor Qs are
high enough that I can ignore them here; the phemt has gobs of gain.
The first step of circuit design is topology.


Where do you plan of getting inductors like that?

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

I doubt we\'d see those squiggles in real life. But we don\'t truly
trust Spice models for things like this; As Mike say, Spice is for
training your instincts. After futzing with a lot of sims, we pick the
best ones and build them.



Again, you completely ignore helpful advice that could teach you how to
go about designing a useful oscillator. The link I provided was a
complete waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

I defy you to make a useful oscillator by ignoring these rules.

I sell lots of products with oscillators. They always work. About the
only rule I respect is Conservation of Energy. This biz is full of
\"Rules\" that are wrong.

Changing the Q of the inductors to 10 has little effect.

However, adding 1pf stray capacitance across each inductor converts the
squiggles into distorted sine waves suitable for driving a load.

Adding mutual coupling of 0.1 between the inductors will smooth the
waveform even more.

However, these changes turn the circuit into a conventional Hartley, which
nobody uses any more. Vastly improved perfomance is obtained with a
conventional Colpitts. This requires fewer inductors which are expensive
and adds one capacitor which is cheaper.

Congratulations. You have invented a Hartley oscillator.

 

[Arnie Dwyer]

Jeroen Belleman <jeroen@nospam.please> wrote:

Arnie Dwyer wrote:
jlarkin@highlandsniptechnology.com wrote:

[...]

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider
advice to be an insult and you ignore it. The resulting Q is
20.42/1e-3 = 20,420

Where do you plan of getting inductors like that?

Don\'t be silly. What matters is the loaded Q. And this oscillator
will run just fine even with an effective Q below 10. The bare
coil Q is mostly irrelevant.

Ignoring the Q is plain sloppy.

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

Many oscillator designs let the transistor current hit zero in order
to limit the amplitude.

The waveform at the source pin is unusable. You should take a look for
yourself.

Most oscillators operate in class C, where the conduction angle is less
than 50%. The transistor is biased off most of the time.

Driving the oscillator into limiting means forward biasing the base-
collector junction. This decreases the tank Q and generates unwanted
harmonics. A much better option is to limit the energy fed into the tank so
it equals the energy dissipated in the tank. This is normally achieved by
reducing the current into the transistor.

Inevitably, the signal at the source ends up
looking nasty, at least in the simulation. In a real circuit, it won\'t
look nearly as bad.

The signal at the source should not look nasty. JL\'s circuit ignores
component parasitics. This makes the sim irrelevant.

If the real circuit does not resemble the simulation, the simulation is
bad. At the frequencies where SPICE is usable, a close correlation between
actual and simulation should be possible, otherwise you are fooling
yourself.

The signal at the source does not have to look ugly, even in the
simulation. JL\'s oscillator can be made to look usable by adding 1pf caps
across each inductor, and adding a bit of mutual coupling to smooth it even
more. However, this turns it into a Hartley, which nobody uses any more.

Inductors are expensive. Changing the circut into a Colpitts gives vastly
better performance and eliminates one inductor.

If you need a purer output, you can always take it
from the top of the tank.

Taking the output from the top of the tank destroys the Q.

> Jeroen Belleman

 

[John Larkin]

On Thu, 3 Feb 2022 16:36:17 -0000 (UTC), Arnie Dwyer <spamme@not.com>
wrote:

John Larkin <jjlarkin@highlandtechnology.com> wrote:

On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spamme@not.com
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer
spamme@not.com> wrote:

jlarkin@highlandsniptechnology.com wrote:

Not actually a Hartley, bacause the Ls are not coupled.

[...]

Without doubt, the worst oscillator I have ever seen anyone design.
You are right. You are not an analog guy.

What\'s wrong with it? It worked first try.

We have surface-mount inductors in stock, many values, but no tapped
inductors in that range.

You don\'t need tapped inductors. You make the feedback with tapped
capacitors. That means capacitors in series.

Sure. Colpitts has been around for about a century. This is a design
group. Instant hostility to ideas is easy.

Instant hostility to idiotic ideas is easy. Did you know you tried to
make an oscillator with inductor Q\'s of 20,420?

Inductor reactance: 2*pi*2.5e-9*1.3e9 = 20.42 ohms

You do not realize the inductor ESR defaults to 1 milliohm if it is not
specified. I have told you about this many times but you consider advice
to be an insult and you ignore it. The resulting Q is 20.42/1e-3 =
20,420

I don\'t consider your advice to be an insult. But real inductor Qs are
high enough that I can ignore them here; the phemt has gobs of gain.
The first step of circuit design is topology.


Where do you plan of getting inductors like that?

Next problem. Have you looked at the waveform at the source pin of your
oscillator? How do you plan on getting useful output from that?

I doubt we\'d see those squiggles in real life. But we don\'t truly
trust Spice models for things like this; As Mike say, Spice is for
training your instincts. After futzing with a lot of sims, we pick the
best ones and build them.



Again, you completely ignore helpful advice that could teach you how to
go about designing a useful oscillator. The link I provided was a
complete waste of time, but here it is again:

https://tinyurl.com/2p9yrxmy

I defy you to make a useful oscillator by ignoring these rules.

I sell lots of products with oscillators. They always work. About the
only rule I respect is Conservation of Energy. This biz is full of
\"Rules\" that are wrong.

Changing the Q of the inductors to 10 has little effect.

However, adding 1pf stray capacitance across each inductor converts the
squiggles into distorted sine waves suitable for driving a load.

Adding mutual coupling of 0.1 between the inductors will smooth the
waveform even more.

We prefer to use parts that we have or can buy easily, so tapped
inductors are not preferred. Possibly one could plop two 0603 Ls next
to one another and get some coupling... that would depend on
placement.

Little surface-mount baluns can be fun, but the inductances are too
high for a 1.5 GHz oscillator. A balun could do our phase splitting
function if we use a single-ended oscillator.

However, these changes turn the circuit into a conventional Hartley, which
nobody uses any more. Vastly improved perfomance is obtained with a
conventional Colpitts. This requires fewer inductors which are expensive
and adds one capacitor which is cheaper.

Congratulations. You have invented a Hartley oscillator.

But you said it\'s not a Hartley! I knew that.

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

Some of the fast comparators have resistor programmable hysteresis,
which might be useful in an RC oscillator.

--

John Larkin Highland Technology, Inc trk

The cork popped merrily, and Lord Peter rose to his feet.
\"Bunter\", he said, \"I give you a toast. The triumph of Instinct over Reason\"

 

[Anthony William Sloman]

On Friday, February 4, 2022 at 10:58:50 AM UTC+11, John Larkin wrote:

On Thu, 3 Feb 2022 16:36:17 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
John Larkin <jjla...@highlandtechnology.com> wrote:
On Thu, 3 Feb 2022 11:40:13 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:
On Wed, 2 Feb 2022 07:23:10 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:
On Wed, 2 Feb 2022 01:55:39 -0000 (UTC), Arnie Dwyer <spa...@not.com> wrote:
jla...@highlandsniptechnology.com wrote:

<snip>

> We prefer to use parts that we have or can buy easily, so tapped inductors are not preferred. Possibly one could plop two 0603 Ls next to one another and get some coupling... that would depend on placement.

It would also depend on the way the 0603 inductors had realised. Presumably there is going to be some kind of heical current path, but you have to know where the axis of the helix lies before you can place the parts in way that will let them couple.

Making the inductor yourself, or getting somebody to make what you need takes more work, but at least you know what you have got.

> Little surface-mount baluns can be fun, but the inductances are too high for a 1.5 GHz oscillator. A balun could do our phase splitting function if we use a single-ended oscillator.

At GHz frequencies you can make transmission line transformers on a printed circuit board. Buried stripline is less dispersive than microstrip on the surface of the board, tracked above a buried ground plane, and you\'d probably need to pay for some kind of Rogers high-frequency substrate, rather than relying on FR4-epoxy resin bonded glass fibre.

However, these changes turn the circuit into a conventional Hartley, which
nobody uses any more. Vastly improved perfomance is obtained with a
conventional Colpitts. This requires fewer inductors which are expensive
and adds one capacitor which is cheaper.

Congratulations. You have invented a Hartley oscillator.

But you said it\'s not a Hartley! I knew that.

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

Some of the fast comparators have resistor programmable hysteresis,
which might be useful in an RC oscillator.

Probably not. Hysteresis is useful when the comparator is fast enough to switch a couple times as the input goes through the switching threshold. If you want a GHz oscillator the comparator probably isn\'t fast enough to generate problematic hash at cross-over.

--
Bill Sloman, Sydney

 

[Jan Panteltje]

On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

I have used the twisted wire oscillator, very stable too, tunable with a potmeter
causing Vce changes that result in Ccb Cce changes etc:
http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG

For lower frequencies the twisted part is longer,

Chip specs may change. add that ECL to make differential output.
There are probably a million types of oscillators, cavities come to mind too.

 

[John Larkin]

On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

I have used the twisted wire oscillator, very stable too, tunable with a potmeter
causing Vce changes that result in Ccb Cce changes etc:
http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG

For lower frequencies the twisted part is longer,

Chip specs may change. add that ECL to make differential output.
There are probably a million types of oscillators, cavities come to mind too.

We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
diff outout pair was cross-connected to the input, and it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

We\'ll try a comparator next.

I could buy a commercial VCO, but they are expensive.


--

John Larkin Highland Technology, Inc trk

The cork popped merrily, and Lord Peter rose to his feet.
\"Bunter\", he said, \"I give you a toast. The triumph of Instinct over Reason\"

 

[whit3rd]

On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:

We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
diff outout pair was cross-connected to the input, and it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

Huh? What is wrong with temperature coefficient in this application?

> We\'ll try a comparator next.

Logic isn\'t intended to oscillate without a network (because oscillation
forces the inputs into the logic margin, not a logically valid state).
The comparator DOES specify behavior at the threshold, so that\'s \'safe\' in
a sense.

> I could buy a commercial VCO, but they are expensive.

So, now you want to make, not an oscillator, but a clock locked to a frequency
standard? Every PC has something like that, like maybe this
<https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY2XP304BVC/12111211>

 

[Jan Panteltje]

On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>:

On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

I have used the twisted wire oscillator, very stable too, tunable with a potmeter
causing Vce changes that result in Ccb Cce changes etc:
http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG

For lower frequencies the twisted part is longer,

Chip specs may change. add that ECL to make differential output.
There are probably a million types of oscillators, cavities come to mind too.

We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
diff outout pair was cross-connected to the input, and it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

We\'ll try a comparator next.

I could buy a commercial VCO, but they are expensive.

Yes
I have some Sirenza VCOs
vco190-1572t.pdf
https://www.ebay.com/itm/402975121352 about 17 canadian $
payed half that in 2013

There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is:
https://www.ebay.com/itm/19141762235 about USD 8

And I have a 960 MHz vco190-964t.pdf

The twisted wire is cheaper

 

[server]

On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whit3rd@gmail.com>
wrote:

On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:

We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
diff outout pair was cross-connected to the input, and it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

Huh? What is wrong with temperature coefficient in this application?

Huh?



--

I yam what I yam - Popeye

 

[server]

On Sun, 06 Feb 2022 19:11:27 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Sun, 06 Feb 2022 09:54:32 -0800) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
sr9qvg5gc3rues8uvihhuop496q51dt7hv@4ax.com>:

On Fri, 04 Feb 2022 07:19:08 GMT, Jan Panteltje
pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Thu, 03 Feb 2022 15:58:32 -0800) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
l61ovg5sopebot77rkmtl61gsu0lu6vgp4@4ax.com>:

I might do the oscillator with an ECL comparator, which gets me the
differential output. That could be RC, or LC.

I have used the twisted wire oscillator, very stable too, tunable with a potmeter
causing Vce changes that result in Ccb Cce changes etc:
http://panteltje.com/pub/2.4GHz_twisted_oscillator_IMG_3629.GIF
http://panteltje.com/pub/twisted_wire_oscillator_IMG_6629.JPG

For lower frequencies the twisted part is longer,

Chip specs may change. add that ECL to make differential output.
There are probably a million types of oscillators, cavities come to mind too.

We connected an MC10EP11 as a pecl gate, with pulldowns to ground. One
diff outout pair was cross-connected to the input, and it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

We\'ll try a comparator next.

I could buy a commercial VCO, but they are expensive.

Yes
I have some Sirenza VCOs
vco190-1572t.pdf
https://www.ebay.com/itm/402975121352 about 17 canadian $
payed half that in 2013

Sirenza advertises GHz VCOs, but doesn\'t seem to want to sell tham in
smallish quantities. MiniCircuits does, but expensive.

There is a cheaper one at about 1.5 GHz on ebay, dont know how good it is:
https://www.ebay.com/itm/19141762235 about USD 8

And I have a 960 MHz vco190-964t.pdf

Varil seems to be gone. I can\'t find them online.

The twisted wire is cheaper

A PCB transmission line oscillator would be OK, I guess.



--

I yam what I yam - Popeye

 

[whit3rd]

On Sunday, February 6, 2022 at 2:59:56 PM UTC-8, jla...@highlandsniptechnology.com wrote:

On Sun, 6 Feb 2022 11:05:53 -0800 (PST), whit3rd <whi...@gmail.com
wrote:
On Sunday, February 6, 2022 at 9:54:47 AM UTC-8, John Larkin wrote:

We connected an MC10EP11 ...d it oscillates
at 1.5 GHz with a fairly square wave out the 2nd diff pair.

Tempco is mediocre. An LC would probably help. Given that I currently
need a 1.5 GHz clock, doing this might be risky.

Huh? What is wrong with temperature coefficient in this application?
Huh?

Anything that oscillates that high probably has enough slew rate, and \'1.5 GHz\' usually
means between 1.45 and 1.55 is good enough. What, if any, criterion is in danger of thermal
drift out of compliance? Do you know that dependence isn\'t desirable? The target of this
clock surely has some temperature coefficients too.

 

[whit3rd]

On Sunday, February 6, 2022 at 11:06:00 AM UTC-8, whit3rd wrote:

... a clock locked to a frequency
standard? Every PC has something like that, like maybe this
https://www.digikey.com/en/products/detail/cypress-semiconductor-corp/CY2XP304BVC/12111211

Oops; I just read the fine print; it only does 500 MHz with direct crystal input.
On the other hand, it has four outputs; you can combine them so the fundamental
is cancelled but the third harmonic is enhanced. Kinda like a tripler, but no tank
required, just resistors.