Filter cap choice for ultra low ripple

On Mon, 10 Aug 2015 13:29:39 +0100, Pomegranate Bastard wrote:

On 09 Aug 2015 18:19:15 GMT, joe hey <joehey@mailinator.com> wrote:

On Sun, 09 Aug 2015 13:40:35 -0400, DecadentLinuxUserNumeroUno wrote:

On Sun, 09 Aug 2015 19:25:14 +0200, David Brown
david.brown@hesbynett.no> Gave us:

On 09/08/15 16:27, Cursitor Doom wrote:
Gentlemen,

What is currently the best choice of filter capacitor for the PSU
section of a high-end signal generator the output of which
(obviously)
really needs to be as ripple-free as humanly possible?
Just in *GENERAL* terms, please guys; don't want to get bogged down
in specifics and calculations at this stage, please!


Decadent Linux may be extraordinarily rude,

(O.T.)

He reminds me of a quite (electronically) brilliant Finnish guy who got
poisoned from his mercury amalgam fillings, became 'as mad as a hatter',
tried to sue the (Finnish) government and the medical establishment, did
probably some other things wrong too, and finally had to leave the
country due to harassment/persecution and went to the USA with his
electronics knowledge, where he continued ranting around where and
whenever he got the opportunity and at the slightest provocation.

It seems that mercury poisoning does that to your brain/constitution.

joe

Well done Joe, you scored a 3'er.
Click to expand...

Yes, he is very funny, almost cute. :)

joe
 
On 10 Aug 2015 17:43:24 GMT, joe hey <joehey@mailinator.com> Gave us:

Yes, he is very funny, almost cute. :)

joe
Click to expand...

Yeah and you almost have an inkling of human intelligence.

Then you go off all palsy wowsy with the group retard. The pommy
bitch is a troll, dumbshit.
 
On Mon, 10 Aug 2015 16:27:54 -0400, DecadentLinuxUserNumeroUno
<DLU1@DecadentLinuxUser.org> wrote:

On 10 Aug 2015 17:43:24 GMT, joe hey <joehey@mailinator.com> Gave us:

Yes, he is very funny, almost cute. :)

joe

Yeah and you almost have an inkling of human intelligence.

Then you go off all palsy wowsy with the group retard. The pommy
bitch is a troll, dumbshit.
Click to expand...

You are a complete and utter imbecile.
 
On Sun, 09 Aug 2015 12:57:33 -0400 DecadentLinuxUserNumeroUno
<DLU1@DecadentLinuxUser.org> wrote in Message id:
<6i1fsahvgduinju2082pbucq08218h2rnu@4ax.com>:

On Sun, 9 Aug 2015 09:03:07 -0700 (PDT), Phil Hobbs <pcdhobbs@gmail.com
Gave us:

If you can afford a volt or so of loss, a 2-stage cap multiplier is the ticket. You can get way over 120 dB rejection of SMPS frequencies.

Cheers

Phil Hobbs

A "high end signal generator" would likely have a linear PS in it, not
a noisy SMPS.
Click to expand...

Sheesh...

You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators
that have switchers in them. Why don't you download a service manual for
an HP 8563E/EC and see for yourself?
 
On Tue, 11 Aug 2015 06:49:55 -0400, JW <none@dev.null> wrote:

On Sun, 09 Aug 2015 12:57:33 -0400 DecadentLinuxUserNumeroUno
DLU1@DecadentLinuxUser.org> wrote in Message id:
6i1fsahvgduinju2082pbucq08218h2rnu@4ax.com>:

On Sun, 9 Aug 2015 09:03:07 -0700 (PDT), Phil Hobbs <pcdhobbs@gmail.com
Gave us:

If you can afford a volt or so of loss, a 2-stage cap multiplier is the ticket. You can get way over 120 dB rejection of SMPS frequencies.

Cheers

Phil Hobbs

A "high end signal generator" would likely have a linear PS in it, not
a noisy SMPS.

Sheesh...

You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators
that have switchers in them. Why don't you download a service manual for
an HP 8563E/EC and see for yourself?
Click to expand...

SMPS have improved greatly during the years.
In the old days SMPS was a no-no in high quality audio applications or
for powering amateur radio HF-transceivers.

These days dithering the switching frequency or manually adjusting the
switching frequency will either blend the spurs into background noise
or at least move spurs out of desired reception frequency range.

However, based on the original question, the OP might be able with
some help to construct a quiet linear (50/60 Hz) PS, but absolutely
not a quiet SMPS.
 
On Tue, 11 Aug 2015 06:49:55 -0400, JW <none@dev.null> Gave us:

>You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators

Oh boy! JW is a repair tech!
 
On Tue, 11 Aug 2015 15:07:55 +0300, upsidedown@downunder.com Gave us:

On Tue, 11 Aug 2015 06:49:55 -0400, JW <none@dev.null> wrote:

On Sun, 09 Aug 2015 12:57:33 -0400 DecadentLinuxUserNumeroUno
DLU1@DecadentLinuxUser.org> wrote in Message id:
6i1fsahvgduinju2082pbucq08218h2rnu@4ax.com>:

On Sun, 9 Aug 2015 09:03:07 -0700 (PDT), Phil Hobbs <pcdhobbs@gmail.com
Gave us:

If you can afford a volt or so of loss, a 2-stage cap multiplier is the ticket. You can get way over 120 dB rejection of SMPS frequencies.

Cheers

Phil Hobbs

A "high end signal generator" would likely have a linear PS in it, not
a noisy SMPS.

Sheesh...

You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators
that have switchers in them. Why don't you download a service manual for
an HP 8563E/EC and see for yourself?

SMPS have improved greatly during the years.
In the old days SMPS was a no-no in high quality audio applications or
for powering amateur radio HF-transceivers.

These days dithering the switching frequency or manually adjusting the
switching frequency will either blend the spurs into background noise
or at least move spurs out of desired reception frequency range.

However, based on the original question, the OP might be able with
some help to construct a quiet linear (50/60 Hz) PS, but absolutely
not a quiet SMPS.
Click to expand...
We are using envelope tracking and DPD. A good old fashioned EMI
filter properly designed and placed at various locations in a design
also serves well.
 
On 8/9/2015 4:12 PM, DecadentLinuxUserNumeroUno wrote:
On Sun, 9 Aug 2015 13:47:44 -0500, "Tim Williams"
tmoranwms@charter.net> Gave us:

Best?

All things considered, same as always, electrolytic. Low cost, high value,
moderate to low ESR, reasonable life (when not run hot).

For any other considerations, it's up to you. Cost? Operating frequency?
Size? General *considerations*, yes, but no generalized *conclusion*.
That's what us designers get paid for. ;-)

Even more generally, however: you seem to dismiss system-level
considerations as obvious! But no, a signal generator is a system. The
power supply only needs to be as well-filtered as the PSRR of the output
stage, preamps and such require for the desired output noise level. And if
there's a regulator stage in there as well, even less (primary) filtering is
needed.

And you can locally filter and regulate stages that are unusually sensitive,
or rebuild them in terms of ratios and ground-referenced voltages, to
increase their PSRR.

There should be absolutely no excuse for excruciatingly clean DC, not since
tubes have gone the way of the dodo. Complementary semiconductors (and good
constant current characteristics) free us from the burden of B+ referenced
signals and low PSRR. :)

Tim

Isn't the term you were searching for 'PARD'?
Click to expand...

Of course he was. He was looking for a description of you:

https://en.wikipedia.org/wiki/Pard_%28legendary_creature%29
 
On Tue, 11 Aug 2015 08:42:03 -0500, John S <Sophi.2@invalid.org> Gave
us:

>Of course he was. He was looking for a description of you:

Fuck off, troll retard. Then die, jackass.
 
On Sun, 9 Aug 2015 13:47:44 -0500, "Tim Williams"
<tmoranwms@charter.net> wrote:

Best?

All things considered, same as always, electrolytic. Low cost, high value,
moderate to low ESR, reasonable life (when not run hot).

For any other considerations, it's up to you. Cost? Operating frequency?
Size? General *considerations*, yes, but no generalized *conclusion*.
That's what us designers get paid for. ;-)

Even more generally, however: you seem to dismiss system-level
considerations as obvious! But no, a signal generator is a system. The
power supply only needs to be as well-filtered as the PSRR of the output
stage, preamps and such require for the desired output noise level. And if
there's a regulator stage in there as well, even less (primary) filtering is
needed.

And you can locally filter and regulate stages that are unusually sensitive,
or rebuild them in terms of ratios and ground-referenced voltages, to
increase their PSRR.

There should be absolutely no excuse for excruciatingly clean DC, not since
tubes have gone the way of the dodo. Complementary semiconductors (and good
constant current characteristics) free us from the burden of B+ referenced
signals and low PSRR. :)

Tim
Click to expand...

Some opamps have terrible high-frequency PSRR. Some have negative PSRR
in some configurations, namely gain from a supply rail to the output.


--

John Larkin Highland Technology, Inc
lunatic fringe electronics

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On Sun, 09 Aug 2015 18:16:55 -0700, whit3rd wrote:

Output buffer amplifiers (transistor follower type) are insensitive to
power supply ripple and noise. Other parts of a 'signal generator' may
need any amount of current, or voltage regulation, or isolation from
other stages. So, it's too complex a problem for 'choice of filter
capacitor'.
Click to expand...

Well, be that as it may, several designers here have been able to
interpret the original, simple question without difficulty and have
provided precisely the pointers I was looking for - and I'm most grateful
to them. It's a shame some other folks have a basic English comprehension
problem; perhaps it's not their first language, but that's life I
guess. :-/
 
On Mon, 10 Aug 2015 04:36:39 -0400, DecadentLinuxUserNumeroUno wrote:

> You obviously do not know how to read a thread.

Yeah, and YOU obviously don't know how to read AT ALL.
 
On 08/11/2015 11:35 AM, John Larkin wrote:
On Sun, 9 Aug 2015 13:47:44 -0500, "Tim Williams"
tmoranwms@charter.net> wrote:

Best?

All things considered, same as always, electrolytic. Low cost, high value,
moderate to low ESR, reasonable life (when not run hot).

For any other considerations, it's up to you. Cost? Operating frequency?
Size? General *considerations*, yes, but no generalized *conclusion*.
That's what us designers get paid for. ;-)

Even more generally, however: you seem to dismiss system-level
considerations as obvious! But no, a signal generator is a system. The
power supply only needs to be as well-filtered as the PSRR of the output
stage, preamps and such require for the desired output noise level. And if
there's a regulator stage in there as well, even less (primary) filtering is
needed.

And you can locally filter and regulate stages that are unusually sensitive,
or rebuild them in terms of ratios and ground-referenced voltages, to
increase their PSRR.

There should be absolutely no excuse for excruciatingly clean DC, not since
tubes have gone the way of the dodo. Complementary semiconductors (and good
constant current characteristics) free us from the burden of B+ referenced
signals and low PSRR. :)

Tim

Some opamps have terrible high-frequency PSRR. Some have negative PSRR
in some configurations, namely gain from a supply rail to the output.
Click to expand...

Yup. Negative PSR is often putrid on 'single supply' op amps, for
instance. Others are pretty good, e.g. the LME49990 (100 dB @ 20 kHz).

It's nice to be able to use the analogue supply rail for biasing,
especially with a single supply, which is another argument for *ahem*
advanced filtering. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net
 
On Tue, 11 Aug 2015 16:18:53 -0400, DefecatingLinuxLuserNumeroUno wrote:

You fucking retard. Phil DID make exactly the suggestion the
oblivious twit missed.
Click to expand...

Yeah, and plenty of other people made useful suggestions, whereas YOU
didn't even understand a simple question!
It's clear all you do here is get mad and confused and start flinging
your excrement around the place, like an angry chimpanzee.
<shrug> Every group has one....
 
On Tue, 11 Aug 2015 06:49:55 -0400 JW <none@dev.null> wrote in Message id:
<udkjsapq9mll1ql7vaika09lv94o42t2rb@4ax.com>:

On Sun, 09 Aug 2015 12:57:33 -0400 DecadentLinuxUserNumeroUno
DLU1@DecadentLinuxUser.org> wrote in Message id:
6i1fsahvgduinju2082pbucq08218h2rnu@4ax.com>:

On Sun, 9 Aug 2015 09:03:07 -0700 (PDT), Phil Hobbs <pcdhobbs@gmail.com
Gave us:

If you can afford a volt or so of loss, a 2-stage cap multiplier is the ticket. You can get way over 120 dB rejection of SMPS frequencies.

Cheers

Phil Hobbs

A "high end signal generator" would likely have a linear PS in it, not
a noisy SMPS.

Sheesh...

You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators
that have switchers in them. Why don't you download a service manual for
an HP 8563E/EC and see for yourself?
Click to expand...

Oops. That's a SA, but the same holds true for generators as well.
Got my 856X mixed up with 866X.
 
On Tue, 11 Aug 2015 08:33:25 -0400 DecadentLinuxUserNumeroUno
<DLU1@DecadentLinuxUser.org> wrote in Message id:
<0qqjsahqbag5bcq8bf45q8nfsc4plaf8is@4ax.com>:

On Tue, 11 Aug 2015 06:49:55 -0400, JW <none@dev.null> Gave us:

You're AlwayWrong as usual. I've repaired plenty of HP/Agilent generators

Oh boy! JW is a repair tech!
Click to expand...

Yup. I fix the T & M equipment (that incompetent pinheads like you blow up
on a daily basis) for several large-ish used equipment dealers. Pay is
excellent, and very little paperwork which I loathe. Best of all, I do it
at home.

Anyway...

A "high end signal generator" would likely have a linear PS in it, not
a noisy SMPS.
Click to expand...

Care to address this particular piece of idiocy, or would you like to
admit you were wrong, AW?
 
On Tue, 11 Aug 2015 08:42:03 -0500 John S <Sophi.2@invalid.org> wrote in
Message id: <mqctvt$9bp$6@dont-email.me>:

On 8/9/2015 4:12 PM, DecadentLinuxUserNumeroUno wrote:
On Sun, 9 Aug 2015 13:47:44 -0500, "Tim Williams"
tmoranwms@charter.net> Gave us:

Best?

All things considered, same as always, electrolytic. Low cost, high value,
moderate to low ESR, reasonable life (when not run hot).

For any other considerations, it's up to you. Cost? Operating frequency?
Size? General *considerations*, yes, but no generalized *conclusion*.
That's what us designers get paid for. ;-)

Even more generally, however: you seem to dismiss system-level
considerations as obvious! But no, a signal generator is a system. The
power supply only needs to be as well-filtered as the PSRR of the output
stage, preamps and such require for the desired output noise level. And if
there's a regulator stage in there as well, even less (primary) filtering is
needed.

And you can locally filter and regulate stages that are unusually sensitive,
or rebuild them in terms of ratios and ground-referenced voltages, to
increase their PSRR.

There should be absolutely no excuse for excruciatingly clean DC, not since
tubes have gone the way of the dodo. Complementary semiconductors (and good
constant current characteristics) free us from the burden of B+ referenced
signals and low PSRR. :)

Tim

Isn't the term you were searching for 'PARD'?


Of course he was. He was looking for a description of you:

https://en.wikipedia.org/wiki/Pard_%28legendary_creature%29
Click to expand...

Heh.

:)
 
On Tue, 11 Aug 2015 14:47:45 -0400, JW <none@dev.null> Gave us:

Yup. I fix the T & M equipment (that incompetent pinheads like you blow up
on a daily basis)
Click to expand...

I do not blow up circuits or test and development gear. I make the
most well grounded test labs in existence, then I develop using them.

Bought about ten 7 inch copper bars just last month to assist in the
facilitation of just that goal.

But I don't expect you to respect ESD protocols either. After all,
you are a presumptuous jackass.
 
On Tue, 11 Aug 2015 14:47:45 -0400, JW <none@dev.null> Gave us:

Care to address this particular piece of idiocy, or would you like to
admit you were wrong, AW?
Click to expand...

Just bought a 40GHz generator last week. Guess what type of supply it
has.

Oh, that's right... you are too stupid to work with anything in that
frequency range.

Just WTF do you think 'high end' means, chump?
 
On Tue, 11 Aug 2015 20:04:19 +0000 (UTC), Cursitor Doom
<curd@notformail.com> Gave us:

On Mon, 10 Aug 2015 04:36:39 -0400, DecadentLinuxUserNumeroUno wrote:

You obviously do not know how to read a thread.

Yeah, and YOU obviously don't know how to read AT ALL.
Click to expand...

You fucking retard. Phil DID make exactly the suggestion the
oblivious twit missed.

Fuck you, doomed bitch.
 
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