Go To Circuits...

[Cursitor Doom]

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.

 

[Phil Hobbs]

On 2023-03-05 12:51, Cursitor Doom wrote:

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.

Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Sun, 05 Mar 2023 17:51:45 +0000, Cursitor Doom <cd@notformail.com>
wrote:

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.

Linear ramp plus comparator time delay.

Triggered LC oscillator with optional phase lock.

Delay-and-width pulse generator, top secret.

GaN based pin driver, ditto.

Power mosfet boosted opamp.

Switchmode power amp

LT3803 based switchers, sepic and flyback

Opamps as voltage regulators

Sallen-Key lowpass filter

3-pole LC lowpass filter, critically damped



I\'ve done a lot of PWM, but it\'s mostly generated digitally lately.

Here\'s an analog PWM generator:

https://www.dropbox.com/s/3j6n35krzxwo73n/23S902B_1_2.pdf?dl=0


How do you usually generate PWM?

 

[Fred Bloggs]

On Sunday, March 5, 2023 at 12:51:54 PM UTC-5, Cursitor Doom wrote:

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

I would steer clear of that noisy thing unless its absolutely necessary.

Cheers,

CD.

 

[Fred Bloggs]

On Sunday, March 5, 2023 at 2:25:57 PM UTC-5, John Larkin wrote:

On Sun, 05 Mar 2023 17:51:45 +0000, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.
Linear ramp plus comparator time delay.

Triggered LC oscillator with optional phase lock.

Delay-and-width pulse generator, top secret.

GaN based pin driver, ditto.

Power mosfet boosted opamp.

Switchmode power amp

LT3803 based switchers, sepic and flyback

Opamps as voltage regulators

Sallen-Key lowpass filter

3-pole LC lowpass filter, critically damped



I\'ve done a lot of PWM, but it\'s mostly generated digitally lately.

Here\'s an analog PWM generator:

https://www.dropbox.com/s/3j6n35krzxwo73n/23S902B_1_2.pdf?dl=0

That\'s some 1970s-ish electronics for you.

How do you usually generate PWM?

 

[John Larkin]

On Sun, 5 Mar 2023 13:01:12 -0800 (PST), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

On Sunday, March 5, 2023 at 2:25:57?PM UTC-5, John Larkin wrote:
On Sun, 05 Mar 2023 17:51:45 +0000, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.
Linear ramp plus comparator time delay.

Triggered LC oscillator with optional phase lock.

Delay-and-width pulse generator, top secret.

GaN based pin driver, ditto.

Power mosfet boosted opamp.

Switchmode power amp

LT3803 based switchers, sepic and flyback

Opamps as voltage regulators

Sallen-Key lowpass filter

3-pole LC lowpass filter, critically damped



I\'ve done a lot of PWM, but it\'s mostly generated digitally lately.

Here\'s an analog PWM generator:

https://www.dropbox.com/s/3j6n35krzxwo73n/23S902B_1_2.pdf?dl=0

That\'s some 1970s-ish electronics for you.

It\'s part of a PM alternator simulator. Should I tell people to stop
buying them?

 

[Fred Bloggs]

On Sunday, March 5, 2023 at 4:08:42 PM UTC-5, John Larkin wrote:

On Sun, 5 Mar 2023 13:01:12 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:
On Sunday, March 5, 2023 at 2:25:57?PM UTC-5, John Larkin wrote:
On Sun, 05 Mar 2023 17:51:45 +0000, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.
Linear ramp plus comparator time delay.

Triggered LC oscillator with optional phase lock.

Delay-and-width pulse generator, top secret.

GaN based pin driver, ditto.

Power mosfet boosted opamp.

Switchmode power amp

LT3803 based switchers, sepic and flyback

Opamps as voltage regulators

Sallen-Key lowpass filter

3-pole LC lowpass filter, critically damped



I\'ve done a lot of PWM, but it\'s mostly generated digitally lately.

Here\'s an analog PWM generator:

https://www.dropbox.com/s/3j6n35krzxwo73n/23S902B_1_2.pdf?dl=0

That\'s some 1970s-ish electronics for you.

It\'s part of a PM alternator simulator. Should I tell people to stop
buying them?

Not all, it\'s an excellent circuit. In the decorative arts community it would be called \"timeless\"- meaning it never goes out of style.

 

[John Larkin]

On Sun, 5 Mar 2023 13:22:52 -0800 (PST), Fred Bloggs
<bloggs.fredbloggs.fred@gmail.com> wrote:

On Sunday, March 5, 2023 at 4:08:42?PM UTC-5, John Larkin wrote:
On Sun, 5 Mar 2023 13:01:12 -0800 (PST), Fred Bloggs
bloggs.fred...@gmail.com> wrote:
On Sunday, March 5, 2023 at 2:25:57?PM UTC-5, John Larkin wrote:
On Sun, 05 Mar 2023 17:51:45 +0000, Cursitor Doom <c...@notformail.com
wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.
Linear ramp plus comparator time delay.

Triggered LC oscillator with optional phase lock.

Delay-and-width pulse generator, top secret.

GaN based pin driver, ditto.

Power mosfet boosted opamp.

Switchmode power amp

LT3803 based switchers, sepic and flyback

Opamps as voltage regulators

Sallen-Key lowpass filter

3-pole LC lowpass filter, critically damped



I\'ve done a lot of PWM, but it\'s mostly generated digitally lately.

Here\'s an analog PWM generator:

https://www.dropbox.com/s/3j6n35krzxwo73n/23S902B_1_2.pdf?dl=0

That\'s some 1970s-ish electronics for you.

It\'s part of a PM alternator simulator. Should I tell people to stop
buying them?

Not all, it\'s an excellent circuit. In the decorative arts community it would be called \"timeless\"- meaning it never goes out of style.

That\'s rev B of the class-D amp. The first pass used a TI audio amp
chip, TPA3255, but it had a suicide wish. The gigantic discrete
mosfets are apparently indestructable.

Here\'s the box. There are three of the PWM boards inside.

http://www.highlandtechnology.com/DSS/P900DS.shtml

You don\'t like the schematic style? I think that one is kind of nice.
Good looking schematics work better.

There are some really hideous schematics around. PADS looks good to me
but only has one layer on schematics, just black on white. I wouldn\'t
mind a usually hidden layer or two, with colors, for notes.

 

[Jan Panteltje]

On a sunny day (Sun, 5 Mar 2023 13:33:22 -0500) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<eeff52ba-cedf-6aed-3b21-0a84597f78e4@electrooptical.net>:

On 2023-03-05 12:51, Cursitor Doom wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.


Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Phil did you ever look into the RTL-SDR world?
https://www.rtl-sdr.com/about-rtl-sdr/
https://www.onelectrontech.com/rtl-sdr-v3-teardown-and-analysis/
Those sticks (and the chips) are available and can replace much of your RF stuff.
I have 4 in use now.....
one as spectrum analyzer + radio receiver (stereo FM) + radar detector + GPS reception + ham radio (AM FM SSB) plus any other RF.
one to receive air traffic, one to receive ship traffic
and one to receive data from my outside weather station.

So first RF thing I turn to.
Of course I have a real Tecsun PL600 radio too
Plus ...
And can replace tons of boat anchors.
https://panteltje.nl/panteltje/xpsa/index.html
old version software, new one has many more buttons and FM stereo and even runs on a Raspberry Pi
or your x86 leptop.
Lots of open source software for it on the internet.

 

[Jan Panteltje]

On a sunny day (Sun, 05 Mar 2023 17:51:45 +0000) it happened Cursitor Doom
<cd@notformail.com> wrote in <68l90i13cpp7v9ht76vjldjl810ipaglg1@4ax.com>:

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.

I dunno about specific circuits, it al depends.
For PWM generation I use Microchip PICs,
those can generate PWM, have ADCs, reference voltage and communication hardware,
hardware comparators plus a lot of other good stuff, internal clock if must be etc etc..:
https://panteltje.nl/panteltje/pic/index.html

There are so many more possibilities:
https://panteltje.nl/panteltje/newsflex/download.html

Much these days is software...
Your question is like asking \'what letter of the alphabet do you use most\'?
Something to do with keyboard layout IIRC.

\'Whatever is available\' comes a lot closer as answer to your question.

 

[Gerhard Hoffmann]

Am 05.03.23 um 19:33 schrieb Phil Hobbs:

On 2023-03-05 12:51, Cursitor Doom wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.


Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Hi,

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

Libbrecht-Hall or current_mirror++ ?
The Howland CCS probably does not need to apply.

Cheers

Gerhard

 

[Anthony William Sloman]

On Monday, March 6, 2023 at 4:51:54 AM UTC+11, Cursitor Doom wrote:

Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Only half-wits get fixated on particular solutions. John Fields thought that the NE555 was the solution to every problem.

If you are such a half-wit, you end up avoiding problems that can\'t be solved with only tool you have in your tool box.

Real-world engineers don\'t have that luxury.

--
Bill Sloman, Sydney

 

[Phil Hobbs]

On 2023-03-06 02:23, Jan Panteltje wrote:

On a sunny day (Sun, 5 Mar 2023 13:33:22 -0500) it happened Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote in
eeff52ba-cedf-6aed-3b21-0a84597f78e4@electrooptical.net>:

On 2023-03-05 12:51, Cursitor Doom wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.


Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Phil did you ever look into the RTL-SDR world?
https://www.rtl-sdr.com/about-rtl-sdr/
https://www.onelectrontech.com/rtl-sdr-v3-teardown-and-analysis/
Those sticks (and the chips) are available and can replace much of your RF stuff.
I have 4 in use now.....
one as spectrum analyzer + radio receiver (stereo FM) + radar detector + GPS reception + ham radio (AM FM SSB) plus any other RF.
one to receive air traffic, one to receive ship traffic
and one to receive data from my outside weather station.

So first RF thing I turn to.
Of course I have a real Tecsun PL600 radio too
Plus ...

Sure, they have their place--I talk about them in my third edition.

Main issue is crappy dynamic range due to 8-bit digitizers. Second
biggest one is crappy phase noise, which they have in common with all
SDR-type systems.

> And can replace tons of boat anchors.

For some purposes, mostly very undemanding ones. My HP 8566B has 30-dB
better close-in phase noise than any SDR-style analyzer I\'ve seen.

https://panteltje.nl/panteltje/xpsa/index.html
old version software, new one has many more buttons and FM stereo and even runs on a Raspberry Pi
or your x86 leptop.
Lots of open source software for it on the internet.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2023-03-06 03:02, Gerhard Hoffmann wrote:

Am 05.03.23 um 19:33 schrieb Phil Hobbs:
On 2023-03-05 12:51, Cursitor Doom wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.


Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Hi,

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it. The key is to drop lots of voltage in the emitter
resistor and bypass the base to the positive supply rather than to
ground. Two poles work better than one. With 5V drop across the
resistor, you can get down to 20 dB below full shot noise, which has
interesting consequences with some lasers.

Libbrecht-Hall or current_mirror++ ?
The Howland CCS probably does not need to apply.

Cheers

Phil

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[whit3rd]

On Monday, March 6, 2023 at 7:39:45 AM UTC-8, Phil Hobbs wrote:

On 2023-03-06 03:02, Gerhard Hoffmann wrote:

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it. The key is to drop lots of voltage in the emitter
resistor and bypass the base to the positive supply rather than to
ground. Two poles work better than one. With 5V drop across the
resistor, you can get down to 20 dB below full shot noise, which has
interesting consequences with some lasers.

Good plan; the transistor has more bandwidth than the op amp.

Two questions: would a MOSFET give equivalent performance to a PNP,
and is a small inductor in series with the emitter resistor any benefit
(I\'m thinking of Rbb/Miller-effect cutoff of the transistor base bypass effectiveness).

 

[Phil Hobbs]

On 2023-03-06 13:40, whit3rd wrote:

On Monday, March 6, 2023 at 7:39:45 AM UTC-8, Phil Hobbs wrote:
On 2023-03-06 03:02, Gerhard Hoffmann wrote:

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it. The key is to drop lots of voltage in the emitter
resistor and bypass the base to the positive supply rather than to
ground. Two poles work better than one. With 5V drop across the
resistor, you can get down to 20 dB below full shot noise, which has
interesting consequences with some lasers.

Good plan; the transistor has more bandwidth than the op amp.

Two questions: would a MOSFET give equivalent performance to a PNP,
and is a small inductor in series with the emitter resistor any benefit
(I\'m thinking of Rbb/Miller-effect cutoff of the transistor base bypass effectiveness).

\"No\" to #1, and \"possibly but generally not\" to #2.

MOSFETs are noisy and have crappy g_M for the same current.

The way I build laser drivers, the emitter resistor is pretty large, so
as to get below the shot noise on the output. The total noise goes down
by 3 dB when the emitter resistor drops 2kT/e (51 mV @ 300K), and I try
to run it at least a few volts.

Thus in order to make a difference over a wide bandwidth, the inductor
it would have to be pretty massive. On the other hand, once its effect
dominated, it would reduce the shot noise characteristic further,
without needing extra headroom. Being (ideally) noiseless, it would
also win linearly rather than as the square root.

Keeping the transistor stable despite a low-Z base bypass might take a
bit of care as well.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Jan Panteltje]

On a sunny day (Mon, 6 Mar 2023 10:27:09 -0500) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<2c5b0e6f-a3fc-03b2-4e9b-e71ffb5f33bf@electrooptical.net>:

On 2023-03-06 02:23, Jan Panteltje wrote:
On a sunny day (Sun, 5 Mar 2023 13:33:22 -0500) it happened Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote in
eeff52ba-cedf-6aed-3b21-0a84597f78e4@electrooptical.net>:

On 2023-03-05 12:51, Cursitor Doom wrote:
Gentlemen,

Over the years, I have found that there is one circuit fragment above
all others that I go back to repeatedly, and that is the PWM
controller in all its guises. I have made more of these than any other
electronic sub-circuit over the last 50 years and they come in handy
for all manner of different applications.
I\'m just curious to know what others here find themselves going back
to repeatedly over the years and would welcome responses from sed
contributors north of the Tropic of Capricorn in this regard.

Cheers,

CD.


Bootstraps, superhets of one sort or another, noise cancellers, cap
multipliers, AC-coupled feedback loops, and a cast of thousands.

Phil did you ever look into the RTL-SDR world?
https://www.rtl-sdr.com/about-rtl-sdr/
https://www.onelectrontech.com/rtl-sdr-v3-teardown-and-analysis/
Those sticks (and the chips) are available and can replace much of your RF stuff.
I have 4 in use now.....
one as spectrum analyzer + radio receiver (stereo FM) + radar detector + GPS reception + ham radio (AM FM SSB) plus any other
RF.
one to receive air traffic, one to receive ship traffic
and one to receive data from my outside weather station.

So first RF thing I turn to.
Of course I have a real Tecsun PL600 radio too
Plus ...

Sure, they have their place--I talk about them in my third edition.

Main issue is crappy dynamic range due to 8-bit digitizers. Second
biggest one is crappy phase noise, which they have in common with all
SDR-type systems.

And can replace tons of boat anchors.

For some purposes, mostly very undemanding ones. My HP 8566B has 30-dB
better close-in phase noise than any SDR-style analyzer I\'ve seen.

OK, sure, 8 bits, but it never hindered me so far..
This is a nice article about GPS receiving with the RTL-SDR:
http://michelebavaro.blogspot.com/2012/04/spring-news-in-gnss-and-sdr-domain.html
Of coure I had to try it, scroll down to \'panteltje\' in that link
note the links to my site are now on panteltje.nl:
https://panteltje.nl/pub/run_50_outside_2728000.gif
https://panteltje.nl/pub/GPS_antenna_T_power_section_IMG_3790.GIF

Bit of mathlab (I used octave)...
Thing is very sensitive...
The big square thing is the active GPS antenna, the small square thing the RTL-SDR [1]
So with a good low noise signal much is possible.
When and were is your third edition coming out?

[1] no idea where I left it, so I have 5 .. hopefully I did not throw it away when moving house...
The latest ones are from ebay and all 1 ppm.

old one with USB connector burned :
https://panteltje.nl/pub/RTL2832_E4000_tuner_PCB_USB_connector_burned_holes_IMG_4671.JPG
put in a new box:
https://www.panteltje.nl/pub/E4000_tuner_in_better_box_with_SMA_IMG_4676.JPG

It does draw some power, the new ones get hot (xtal is temperature controlled).

Latest ones go down to 500 kHz, had build in bias circuit:
https://www.ebay.com/itm/272411458376
have not tried that one, seller is OK, have 2 from them.

https://panteltje.nl/panteltje/xpsa/index.html
old version software, new one has many more buttons and FM stereo and even runs on a Raspberry Pi
or your x86 leptop.
Lots of open source software for it on the internet.

 

[Gerhard Hoffmann]

Am 06.03.23 um 16:39 schrieb Phil Hobbs:

On 2023-03-06 03:02, Gerhard Hoffmann wrote:

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it.

I suppose PNP b/c of the slightly better voltage noise than a
similar NPN, and the inductor is just the 6 dB/oct drop, or is there
more to it?

The key is to drop lots of voltage  in the emitter
resistor and bypass the base to the positive supply rather than to
ground.  Two poles work better than one.  With 5V drop across the
resistor, you can get down to 20 dB below full shot noise, which has
interesting consequences with some lasers.

Now I\'m curious. What would these consequences be?

Cheers
Gerhard

 

[Phil Hobbs]

On 2023-03-08 13:30, Gerhard Hoffmann wrote:

Am 06.03.23 um 16:39 schrieb Phil Hobbs:
On 2023-03-06 03:02, Gerhard Hoffmann wrote:

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it.

I suppose PNP b/c of the slightly better voltage noise than a
similar NPN, and the inductor is just the 6 dB/oct drop, or is there
more to it?

Common-cathode laser. The \'simulated inductor\' thing is just a cap
multiplier with the base bypassed to the far end of the emitter resistor
rather than to ground. Like this:

V+
0--*--RRRR--* *------------------*
| \\ / |
| V / ---
| ------- \\ / ~~ >
| C C | V ~~ >
*- C C------*-----RRRR---0 Vctl ---
C C |
GGG

with maybe another pole (also bypassed to V+) for good measure, and a
nice quiet op amp looking at the same resistor, doing the DC regulation.

The key is to drop lots of voltage  in the emitter resistor and bypass
the base to the positive supply rather than to ground.  Two poles work
better than one.  With 5V drop across the resistor, you can get down
to 20 dB below full shot noise, which has interesting consequences
with some lasers.

Now I\'m curious. What would these consequences be?

Amplitude squeezing, sometimes. Thirty-odd years ago, all sorts of
quantum optics folk were working on \"squeezed states\", in which the
Heisenberg uncertainty product <delta A><delta phi> was modified to give
less <delta A> and more <delta phi>.

It was all Ti:sapphire lasers and optical parametric oscillators and
four-wave mixing and stuff--tables full of expensive parts on expensive
mounts, conferences with big banquets, yada yada, all to get about a
decibel worth.

Then these Japanese guys (whose paper I can\'t seem to locate) took a
LN2-cooled diode laser, biased it with a stack of batteries and a big
resistor, and got 3 dB, because the bias current was way sub-Poissonian
and that constrained the pumping.

They had the world record for some years, iirc. (I love things like
that--doing something amazing with almost zero apparatus.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2023-03-08 14:06, Phil Hobbs wrote:

On 2023-03-08 13:30, Gerhard Hoffmann wrote:
Am 06.03.23 um 16:39 schrieb Phil Hobbs:
On 2023-03-06 03:02, Gerhard Hoffmann wrote:

What are the Go To Laser drivers when the first 5 requirements
are stability and low noise? Just DC, no modulation.

A PNP simulated inductor with a very long tail and a low noise op amp
wrapped round it.

I suppose PNP b/c of the slightly better voltage noise than a
similar NPN, and the inductor is just the 6 dB/oct drop, or is there
more to it?

Common-cathode laser.  The \'simulated inductor\' thing is just a cap
multiplier with the base bypassed to the far end of the emitter resistor
rather than to ground.  Like this:

V+
0--*--RRRR--*       *------------------*
   |         \\     /                   |
   |          V   /                   ---
   |         -------                  \\ / ~~
   |  C C      |                       V  ~~
   *- C C------*-----RRRR---0 Vctl    ---
      C C                              |
                                      GGG

with maybe another pole (also bypassed to V+) for good measure, and a
nice quiet op amp looking at the same resistor, doing the DC regulation.

The key is to drop lots of voltage  in the emitter resistor and
bypass the base to the positive supply rather than to ground.  Two
poles work better than one.  With 5V drop across the resistor, you
can get down to 20 dB below full shot noise, which has interesting
consequences with some lasers.

Now I\'m curious. What would these consequences be?

Amplitude squeezing, sometimes.  Thirty-odd years ago, all sorts of
quantum optics folk were working on \"squeezed states\", in which the
Heisenberg uncertainty product <delta A><delta phi> was modified to give
less <delta A> and more <delta phi>.

It was all Ti:sapphire lasers and optical parametric oscillators and
four-wave mixing and stuff--tables full of expensive parts on expensive
mounts, conferences with big banquets, yada yada, all to get about a
decibel worth.

Then these Japanese guys (whose paper I can\'t seem to locate) took a
LN2-cooled diode laser, biased it with a stack of batteries and a big
resistor, and got 3 dB, because the bias current was way sub-Poissonian
and that constrained the pumping.

Machida and Yamamoto, it was. One of their early pubs is
<https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.60.792>

They had the world record for some years, iirc.  (I love things like
that--doing something amazing with almost zero apparatus.)

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com