Chris wrote:
Just practical question.. How would one measure noise at this
level? If I were evaluate this what would I need?
Generally, one starts with an extremely low noise amplifier. Note
that isolating the very low frequency AC components from the DC
component is a substantial
Charles P.
Steinmetz
Gesendet: Freitag, 1. Februar 2013 18:35
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Low noise power supplies?
Joe wrote:
Back when I was in product engineering there was a VCO design that
used a superfilter circuit. It consisted
Are 4 and 5 regulated? Or is the zener picked to compensate for the VBE
drops?
Any of these circuits where the output transistor is in an emitter
follower configuration will have its noise effected by the load current,
since that current directly effects the output transistor
Bob Camp, Thursday, January 31 11:36 AM (Local NY time):
((...snip...))
With a good enough voltmeter you could carry the analogy one step further
and compute an ADEV like number on the output voltage. I suspect that's
carrying things a bit far.
No, I disagree. That's not carrying things nearly
.
Thanks,
Burt, K6OQK
Subject: Re: [time-nuts] Low noise power supplies?
A non-standard but repeatable way to measure power supply noise is to use a
Transmission Impairment Measuring Set (TIMS) such as the HP3945(6)A or 3551
(2)A. These were intended for use in pairs to assess analog telephone
Hi
The circuit I described, is (as stated) quiet down to 100 Hz. It's 3 db
bandwidth is well below 10 Hz with the 47 uF cap. If you need it quiet down to
10 Hz or 0.1 Hz, you will need to buy a few more caps. It's still not
rocket science.
For most OCXO or atomic standard testing
-nuts-boun...@febo.com
[mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob Camp
Gesendet: Freitag, 1. Februar 2013 13:38
An: Discussion of precise time and frequency measurement
Betreff: Re: [time-nuts] Low noise power supplies?
Hi
The circuit I described, is (as stated) quiet down
Hello, interesting discussion about noise.
It's all way over my knowledge, so my contribution
to discussion maybe is only noise :)
Re batteries I agree with Mark, see below:
Il 2013-01-31 06:42 Mark Sims ha scritto:
A123 20Ah LiFePO4 cells have an internal resistance in the milliohm
range.
Hi
If you use an electrolytic cap on the base (tantalum or what ever) the
leakage current will mess up the output a bit. It does *eventually* die down
some, but you may have to wait for days...
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]
@febo.com
Subject: Re: [time-nuts] Low noise power supplies?
Are 4 and 5 regulated? Or is the zener picked to compensate for the VBE
drops?
Any of these circuits where the output transistor is in an emitter
follower configuration will have its noise effected by the load current,
since
Content-Type: text/plain; charset=ISO-8859-1
In message 2bf4f4e8c8207ae0f94a7e1a1e63c...@quipo.it, Fabio Eboli writes:
Il 2013-01-31 06:42 Mark Sims ha scritto:
A123 20Ah LiFePO4 cells have an internal resistance in the milliohm
range. [...]
Low internal resistance in batteries is an
Joe wrote:
Back when I was in product engineering there was a VCO design that
used a superfilter circuit. It consisted of a pass transistor and
a filter cap from base to ground. The gain of the transistor
multiplied the effective capacitance. I have not seen this configuration since.
They
Sorry, Poul-Henning Kamp, I answered directly
to your mail address, I repost it here...
Il 2013-02-01 18:09 Poul-Henning Kamp ha scritto:
Content-Type: text/plain; charset=ISO-8859-1
In message 2bf4f4e8c8207ae0f94a7e1a1e63c...@quipo.it, Fabio Eboli
writes:
Il 2013-01-31 06:42 Mark
to the fun with wood group send a blank email to
funwithwood-subscr...@yahoogroups.com
- Original Message -
From: David davidwh...@gmail.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Thursday, January 31, 2013 11:10 PM
Subject: Re: [time-nuts] Low
to the fun with wood group send a blank email to
funwithwood-subscr...@yahoogroups.com
- Original Message -
From: John Miles jmi...@pop.net
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Sent: Friday, February 01, 2013 12:03 AM
Subject: Re: [time-nuts] Low
Feb 2013 13:39:14
To: Discussion of precise time and frequency measurementtime-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies?
Well, I stand corrected. Weren't the TM 500 instruments
Content-Type: text/plain; charset=ISO-8859-1
In message blu170-w704bd0870332925fa3e67dce...@phx.gbl, Mark Sims writes:
A123 20Ah LiFePO4 cells have an internal resistance in the milliohm
range. Their M1 26650 format cells are around 8 milliohms. Most
high capacity (3000 mAh) 18650
Content-Type: text/plain; charset=ISO-8859-1
In message bay162-w38a3ac22812ac79a0fbfc6df...@phx.gbl, Tom Knox writes:
Starting with a hp supply this finesse regulator will really clean
up the output. http://www.wenzel.com/documents/finesse.html
I've played with that, and it can do
I've measured AA nicad impedance at a few kHz, but it was years ago. My
recollection is it was in tens of milliohms.
ESR does have a frequency dependency. In the same time frame, I was
trying to find a simple non-instrusive way to detect alkaline cells
versus nicads. The key was in impedance
Poul-Henning Kamp wrote:
Content-Type: text/plain; charset=ISO-8859-1
In messagebay162-w38a3ac22812ac79a0fbfc6df...@phx.gbl, Tom Knox writes:
Starting with a hp supply this finesse regulator will really clean
up the output. http://www.wenzel.com/documents/finesse.html
I've
On 1/31/2013 12:20 AM, Bruce Griffiths wrote:
With some care its possible to make the emitter current of the shunt
transistor approximately PTAT so that, at least for small signals the
temperature dependence of the rejection is reduced significantly.
Sorry, what does PTAT mean? I'm not
PTAT == Proportional To Absolute Temperature
Dave
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Lester wrote:
For a regulated power supply, make one using a 723. The 723 has
far lower noise out than the monolithic regulators.
If you are willing to design your own regulator using a 723, you may
as well use a few more parts to get a much better result. Neither
the internal reference
Am 31.01.2013 03:16, schrieb Richard (Rick) Karlquist:
I know this topic has been discussed in the past on the list, but
a colleague is asking if there are any off the shelf low
noise power supplies for testing oscillators. Something
The E5052B signal source analyzer has low noise power
and
Am 31.01.2013 05:28, schrieb Chris Albertson:
For once the best is also cheap: Batteries.
But not all batteries are the same. You want one with low internal
resistance, so a lead acid flooded battery will be the best.
Fred Walls Co have done tests on batteries. The article is
somewhere on
-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Charles P. Steinmetz
Sent: Thursday, January 31, 2013 5:33 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low noise power supplies?
Lester wrote:
For a regulated power supply
If the main concern is about low-frequency noise the LT1763 might be worth
considering for a simple solution, as it is capable of lower noise than the
data sheet shows. With a bypass capacitor (Cbyp) fitted, the noise floor is
~30nV/rtHz. Although the data sheet only recommends up to 10nF for
Rick,
the E3610A is really clean.
If that isn't good enough, there are some audio-related circuits like
the ALWSR.
http://www.andrewweekes.talktalk.net/Manuals/ALWSR_rev2.9_Iss005s.pdf
It's based on a Walt Jung design (Analog Devices).
Here's the man himself with tons of valuable information
Hi Rick,
I'll answer the question with anther question -- how does one properly measure
power supply noise? Does it boil down to a single number, a couple of key
numbers, or is it a plot, or several plots?
I ask because without some sort of standard test and reporting method it just
becomes a
On 31 January 2013 04:28, Chris Albertson albertson.ch...@gmail.com wrote:
On Wed, Jan 30, 2013 at 6:16 PM, Richard (Rick) Karlquist
rich...@karlquist.com wrote:
I know this topic has been discussed in the past on the list, but
a colleague is asking if there are any off the shelf low
noise
...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak
Sent: Thursday, January 31, 2013 9:43 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low noise power supplies?
Hi Rick,
I'll answer the question with anther question -- how does one properly
Of Tom Van Baak
Sent: Thursday, January 31, 2013 9:43 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low noise power supplies?
Hi Rick,
I'll answer the question with anther question -- how does one properly
measure power supply noise? Does it boil down
On 31.01.2013 09:05, Adrian wrote:
Rick,
the E3610A is really clean.
The discussion is interesting, but the original question did ask about
off the shelf so I have been watching for any mention of HP/Agilent
precision power supplies. The E3610A specification says 200 uVrms, 2mv
pp ripple
is considered low power supply noise? Can you give
me some numbers and over what bandwidth?
Thanks,
Burt, K6OQK
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies?
Hi
To answer the original question - Power Design makes some pretty quiet
bench
supplies. If you
On 31 January 2013 17:11, John Ackermann N8UR j...@febo.com wrote:
And this (very interesting) thread brings up the question of measurement
methods. Some time ago I searched around and didn't find much on a standard
way to measure noise on low voltage DC supplies.
John
Did you try the
-nuts@febo.com
Sent: Thursday, 31 January 2013, 18:02
Subject: Re: [time-nuts] Low noise power supplies?
Hi
A very common way to check one is to use the HP 3561 off of the old 3048
phase noise test set. With a simple op amp based preamp you can easily get
down below 3 nv / sqrt(Hz). With more
Oops,
that should be HP4945(6)A not 3945
Robert.
From: Robert Atkinson robert8...@yahoo.co.uk
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Thursday, 31 January 2013, 18:46
Subject: Re: [time-nuts] Low noise power supplies
Not sure if anyone posted this here yet, but Abracom has a very low noise
(7nV/RtHz at 1KHz) power source for VCO's etc, with various outputs. It's
sold on DIgikey or Mouser I think.
Here is a review of that unit:
_http://jaunty-electronics.com/blog/category/reviews/_
-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of saidj...@aol.com
Sent: Thursday, January 31, 2013 3:58 PM
To: time-nuts@febo.com; les...@veenstras.com
Subject: Re: [time-nuts] Low noise power supplies?
Not sure if anyone posted this here yet, but Abracom has a very low noise
(7nV
-nuts-boun...@febo.com] On
Behalf Of Tom Van Baak
Sent: Thursday, January 31, 2013 9:43 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Low noise power supplies?
Hi Rick,
I'll answer the question with anther question -- how does one properly
measure power supply
Content-Type: text/plain; charset=ISO-8859-1
In message C7259FFFCD3E42C2815B939BA386A0A8@pc52, Tom Van Baak writes:
We have rigorous ways to compare and report oscillator performance;
both as numbers and as plots. Is there something equivalent for
power supplies?
Phase Noise measured on
tvb wrote:
I'll answer the question with anther question -- how does one
properly measure power supply noise? Does it boil down to a single
number, a couple of key numbers, or is it a plot, or several plots?
There are a number of standard ways, some of which have been
mentioned by others,
Charles,
thanks for posting. That is the LTC application note I had in mind.
And here is Bruce's contribution to low noise PS design and measurement:
http://www.ko4bb.com/~bruce/LowNoisePowerSupplies.html
Don't miss to scroll fully down. There is a link to an IEEE paper
discussing chemical
...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of saidj...@aol.com
Sent: Thursday, January 31, 2013 3:58 PM
To: time-nuts@febo.com; les...@veenstras.com
Subject: Re: [time-nuts] Low noise power supplies?
Not sure if anyone posted this here yet, but Abracom has a very low noise
(7nV
Hi
If you are driving a spectrum analyzer, the 10,000X mentioned in the app note
simply is not needed. A gain of 10X or less will get you to below 2 nv /
sqrt(Hz) at 100 Hz and beyond. A 10 Hz blocking cap does not need to be a 24
hours to stabilize device. An AD 797, a couple of metal film
Bob wrote:
An AD 797, a couple of metal film resistors, and a fairly large (say
47 uf) plastic cap work pretty well.
The band from 10 Hz down to 0.1 or 0.01 Hz is generally important
when testing oscillators. To keep the 797 input noise density below
a few nV per root Hz, the terminations
One more thought: Many oscillators have internal regulators that are not
nearly as good as what you can build. No sense using an external supply
with 5 nV per root Hz noise density if it will be re-regulated inside
the oscillator by a circuit that has a noise density of 250 nV per root Hz.
You haven't seen it used because it doesn't work very well. It appeared in
a few pieces of Heathkit equipment but I don't think HP or Tek used it at
all. Any AC component of base to collector voltage has a small but definite
effect on Vbe which transfers voltage in the reverse direction from
I have seen it used in a couple of Tektronix TM500 instruments but the
purpose may have been to generate a lower voltage power supply rail
instead of noise reduction. Tektronix often added LC sections on
their switching power supply outputs and distributed smaller LC
sections to prevent coupling
Are 4 and 5 regulated? Or is the zener picked to compensate for the VBE
drops?
Any of these circuits where the output transistor is in an emitter
follower configuration will have its noise effected by the load current,
since that current directly effects the output transistor
The typical test supply on a bench for clean VCO testing is a small gel cell
battery. For a regulated power supply, make one using a 723. The 723 has
far lower noise out than the monolithic regulators.
Lester B Veenstra MØYCM K1YCM W8YCM
les...@veenstras.com
US Postal Address:
5 Shrine Club
On Wed, Jan 30, 2013 at 6:16 PM, Richard (Rick) Karlquist
rich...@karlquist.com wrote:
I know this topic has been discussed in the past on the list, but
a colleague is asking if there are any off the shelf low
noise power supplies for testing oscillators. Something
a cut above an HP brick
On 1/30/13 8:28 PM, Chris Albertson wrote:
For once the best is also cheap: Batteries.
But not all batteries are the same. You want one with low internal
resistance, so a lead acid flooded battery will be the best.
Most NiCd have very low internal resistance.. much lower than lead acid.
On Wed, Jan 30, 2013 at 9:05 PM, Jim Lux jim...@earthlink.net wrote:
On 1/30/13 8:28 PM, Chris Albertson wrote:
For once the best is also cheap: Batteries.
But not all batteries are the same. You want one with low internal
resistance, so a lead acid flooded battery will be the best.
Lester Veenstra wrote:
The typical test supply on a bench for clean VCO testing is a small gel cell
battery. For a regulated power supply, make one using a 723. The 723 has
far lower noise out than the monolithic regulators.
Depends on the variety of 723 some are noisier than others.
Some
YUP,
The C-130 aircraft uses larger than car battery size wet NiCd to fire up the
Genset that is used to start the Tubo-prop jet engines. Definitely has lower
resistance then the Lead-Acid wet cell.
BillWB6BNQ
Arthur Dent wrote:
But the only NiCd I know about are the AA sized ones.
I
Hi Rick;
Starting with a hp supply this finesse regulator will really clean up the
output. http://www.wenzel.com/documents/finesse.html
Best Wishes;
Thomas Knox
Date: Wed, 30 Jan 2013 18:16:46 -0800
From: rich...@karlquist.com
To: time-nuts@febo.com
Subject: [time-nuts] Low noise power
Ceramic caps can be microphonic. Just something to be on the look out.
Not so much with leaded ceramics, but more of a problem with surface mounts.
Tantalums are prone to overvoltage failure. Best to really overspec them
regarding voltage.
Note that some LDOs are not stable with really low
On Mon, 28 Nov 2011 01:05:22 -0800
gary li...@lazygranch.com wrote:
Ceramic caps can be microphonic. Just something to be on the look out.
Not so much with leaded ceramics, but more of a problem with surface mounts.
Ceramic caps have a lot of other problems too, like capacitance
derating on
On Mon, 28 Nov 2011 16:16:58 -0500 (EST)
saidj...@aol.com wrote:
Use foil caps to avoid vibration-microphonics. Very expensive, but hey you
get what you pay for. Use Tantalum caps if bulk bypassing is needed, using
multiple 100uF units if necessary. The design is not right if you need more
Hi Attila,
I like 2MHz switchers because they use small components (inductors and
capacitors) and are easier to filter out at our usual frequencies of interest.
The LT3502A for example works at 2.2MHz, which gives harmonics at 8.8MHz
and 11MHz, far enough away from 10.0MHz to avoid
To: time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies - dont' use Electrolytics
Hi Attila,
I like 2MHz switchers because they use small components (inductors and
capacitors) and are easier to filter out at our usual frequencies of
interest.
The LT3502A for example works at 2.2MHz
Were getting of off the original thread about Electrolytics versus other
caps a bit..
A switcher at 2.2MHz does not have single frequency spikes in its power
spectrum, but a rather wideband distribution.
Yes, that's Fourier 101 basics.
But what matters to Time nuts is if the switcher is
I molt them in a high-power charge-pump. The same with WIMA MKS.
At normal usage they will last forever and work even at low temperature
whereas normal Al caps won't.
- Henry
gary schrieb:
At sane temperatures, OSCONs are very good. Who runs their gear hot
enough to boil water?
On Fri, 25 Nov 2011 22:25:37 -0800
Chris Albertson albertson.ch...@gmail.com wrote:
One question: How does one avoid using electrolytic caps if you need
(say) 1,000uF or even 100uF. Those would be some mighty big film
caps.
I think, aluminium electrolytics are meant, as these have a lot of
In message cabbxvhvnsaxbx5uorjtqesttd50yedyavkgxh52bpspuayt...@mail.gmail.com
, Chris Albertson writes:
One question: How does one avoid using electrolytic caps if you need
(say) 1,000uF or even 100uF. Those would be some mighty big film caps.
One detail, often overlooked, is that
On Sat, Nov 26, 2011 at 2:13 AM, gary li...@lazygranch.com wrote:
At sane temperatures, OSCONs are very good. Who runs their gear hot enough
to boil water?
National Fire Protection Agency (NFPA) 2007 edition of their design
regulations state the electronics worn by Fire Fighters must work at
On Fri, Nov 25, 2011 at 10:36 PM, Raj vu2...@gmail.com wrote:
How about this way: Amplifying capacitance.. (Base/Ground cap * Beta)
http://sound.westhost.com/project15.htm
The above actually uses several quite large electrolytic. It is a
good example of why you NEED to use them.
Maybe
On 11/26/11 11:13 AM, Chris Albertson wrote:
On Fri, Nov 25, 2011 at 10:36 PM, Rajvu2...@gmail.com wrote:
How about this way: Amplifying capacitance.. (Base/Ground cap * Beta)
http://sound.westhost.com/project15.htm
The above actually uses several quite large electrolytic. It is a
good
Electrolytic caps have an extremely poor lifetime (MTBF). Sanyo on their
website state 50K Hrs at 50C.
This means only 6250 MTBF hours at 80C for one single cap. MTBF gets worse
the more caps are being used of course. I have seen some Panasonic
electrolytics state only 2000 hours MTBF at
Many of us have seen electronic equipment last longer then one year.
Some of use even have still working antiques with old eletro caps.
Those short lifetimes assume a worse case, usually with a very high
ripple current. IOf you can reduce the ripple the MTBF goes up.
One question: How does one
How about this way: Amplifying capacitance.. (Base/Ground cap * Beta)
http://sound.westhost.com/project15.htm
One question: How does one avoid using electrolytic caps if you need
(say) 1,000uF or even 100uF. Those would be some mighty big film
caps.
To second the older electronics:
I maintain nearly 100 analytical instruments. The old designs(1970-late
80's) are almost all electrolytic caps and none of the caps have ever
failed. When I do find a bad cap it's always in a modern design. A high
frequency switcher with under rated caps. When i
At sane temperatures, OSCONs are very good. Who runs their gear hot
enough to boil water?
http://edc.sanyo.com/pdf/e_oscon.pdf
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On Wed, 23 Nov 2011 04:50:49 -0800
Chuck Forsberg WA7KGX N2469R c...@omen.com wrote:
How well would a pair of cascaded 3 terminal regulators do - say a 7815
feeding a 7812.
78xx Regulators are quite noisy. You can use them to filter the
noise of a cheap DC/DC converter, but i wouldnt use them
and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time nuts circuitry
How well would a pair of cascaded 3 terminal regulators do - say a 7815
feeding a 7812.
How sensitive are each of a Thunderbolt's 3 supplies to noise?
On 11/23/2011 04:13
At 2:28 PM + 11/24/11, time-nuts-requ...@febo.com wrote:
Message: 3
Date: Thu, 24 Nov 2011 13:22:38 +0100
From: Attila Kinali att...@kinali.ch
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time nuts
78xx Regulators are quite noisy. You can use them to filter the
noise of a cheap DC/DC converter, but i wouldnt use them feed
high precision electronics. There are a lot better designs these days.
Hi Attila,
Would you mind recommending some low-noise regulators? Perhaps for
both low and high
On Nov 23, 2011, at 5:50 AM, Chuck Forsberg WA7KGX N2469R wrote:
How sensitive are each of a Thunderbolt's 3 supplies to noise?
This doesn't break down the sensitivities to noise, but Tom shows
a range of TBolt output noise for different 3 voltage power supplies:
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time nuts circuitry
At 2:28 PM + 11/24/11, time-nuts-requ...@febo.com wrote:
Message: 3
Date: Thu, 24 Nov 2011 13:22:38 +0100
From: Attila Kinali att
on the output.
-Original Message-
From: Joe Gwinn joegw...@comcast.net
Sender: time-nuts-boun...@febo.com
Date: Thu, 24 Nov 2011 10:14:35
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise
Hi All
,
I find it interesting that this subject came up just as I was looking
into cleaning up some of my supplies that power my RB's.
Anyway
I just bought two of these to play with
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItemitem=130605436528
and they're based on this device...
Hi
The Linear LT1764 is reasonably quiet / high current / low dropout. Don't count
on getting all three at once.
Bob
On Nov 24, 2011, at 12:45 PM, Kevin Rosenberg ke...@rosenberg.net wrote:
78xx Regulators are quite noisy. You can use them to filter the
noise of a cheap DC/DC converter,
The LTC datasheet crows about low current in dropout. Yeah, it's worth
crowing about since not all chip use what is called a sat catcher
circuit. High current in dropout with PNP pass devices can be a problem.
I've seen Micrel regulators that are horrible in dropout. The sat
catcher is yet
On Nov 24, 2011, at 4:46 PM, Bob Camp wrote:
The Linear LT1764 is reasonably quiet / high current / low dropout. Don't
count on getting all three at once.
Thanks, Bob!
Kevin
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On Thu, 24 Nov 2011 11:45:05 -0700
Kevin Rosenberg ke...@rosenberg.net wrote:
78xx Regulators are quite noisy. You can use them to filter the
noise of a cheap DC/DC converter, but i wouldnt use them feed
high precision electronics. There are a lot better designs these days.
Would you
On Tue, 22 Nov 2011 12:38:43 -0500
Bob Camp li...@rtty.us wrote:
There are a couple of circuits (low noise op-amp based)
that can generate lower noise than what he's shown.
What circuits would that be?
Attila Kinali
--
The trouble with you, Shev, is you don't say
How well would a pair of cascaded 3 terminal regulators do - say a 7815
feeding a 7812.
How sensitive are each of a Thunderbolt's 3 supplies to noise?
On 11/23/2011 04:13 AM, Attila Kinali wrote:
On Tue, 22 Nov 2011 12:38:43 -0500
Bob Campli...@rtty.us wrote:
There are a couple of circuits
Hi
Interesting site - Thanks!
A couple of observations:
There are a couple of circuits (low noise op-amp based) that can generate lower
noise than what he's shown.
You need to be careful looking at his results. A lot of what he shows is the
result of changing the model used for the output
In imaging systems, where the noise on the pixel supply was critical, I had
good luck using a buck switcher followed by an LDO, whose maximum PSRR point
determined the operating frequency of the switcher. All normal techniques for
removing SMPS noise still apply.
I used the ISL9000
Hi
With modern high frequency switchers, often a LC filter between the switcher
and the LDO does the trick. The gotcha is that not all the energy is conducted.
Radiated energy quickly becomes the issue….
Depending on what you are timing that may be more or less of an issue. 10 MHz
Omitting the output bypass cap in the single transistor Wenzel
cancellation circuit is somewhat misleading in that it reduces the high
frequency attenuation,
All his other circuits include such caps.
A simple tweak (adjusting a resistor ratio) which makes the shunt
transistor collector current
Another potential problem is that the cascaded emitter follower circuit
shown is likely to oscillate in the VHF region.
An unbypassed resistor in series with the base of each emitter follower
should be used.
Bruce
Bruce Griffiths wrote:
Omitting the output bypass cap in the single transistor
In message 6f9e458f-b701-49c1-8d83-ebda35784...@ulrich-bangert.de, Ulrich Ban
gert writes:
It seems to turn out as if the well known Wenzel suggestions for voltage
regulator finesse were not state of the art [...]
I've played a bit with the Wenzel circuits and they can provide truly
outstanding
As Bob Pease used to say: Spice plots are good for padding bird cages, not
much else :)
Hittite has a fantastic new ultra low noise LDO for VCO's. Haven't had a
chance to check that out, but it looks very promising. Has anyone tried that
part here?
Also, remember that those caps are
The Hittite parts (there are two versions, one with 1 output and one with
4 outputs, HMC860 and HMC976) unfortunately have a foot note
on the data sheet that indicates
that the noise numbers are good in the application circuit, which
happens to include large capacitors. The capacitors are really
measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time nuts circuitry
As Bob Pease used to say: Spice plots are good for padding bird cages, not
much else :)
Hittite has a fantastic new ultra low noise LDO for VCO's. Haven't had a
chance to check that out
-
From: saidj...@aol.com
Sender: time-nuts-boun...@febo.com
Date: Tue, 22 Nov 2011 14:18:20
To: time-nuts@febo.com
Reply-To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time nuts circuitry
As Bob Pease used
they
excel in other performance criteria.
-Original Message-
From: Azelio Boriani azelio.bori...@screen.it
Date: Tue, 22 Nov 2011 21:45:47
To: li...@lazygranch.com; Discussion of precise time and frequency
measurementtime-nuts@febo.com
Subject: Re: [time-nuts] Low noise power supplies for time
Yes, load isolation is a valuable feature I left out. Perhaps the key feature.
The audio designers like it for channel separation.
--Original Message--
From: ed breya
Sender: time-nuts-boun...@febo.com
To: time-nuts@febo.com
ReplyTo: Discussion of precise time and frequency measurement
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