Re: [time-nuts] Totally unrelated, but..

...@febo.com] On Behalf Of Chuck Harris Sent: Wednesday, December 7, 2016 1:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. I don't think so. I first ran into a batch of LM340-5's that were excellent oscillators back in the 1970's... long

Re: [time-nuts] Totally unrelated, but..

I am pretty sure that I ran across this once as well with the 7800/LM340 series in the early 1980s with parts from a major manufacturer like Motorola, National, or Texas Instruments; the regulators ran hot and the output voltages were slightly low no matter what decoupling arrangements were made

Re: [time-nuts] Totally unrelated, but..

On Thu, 8 Dec 2016 02:25:14 +0100, you wrote: >Am 08.12.2016 um 01:20 schrieb Scott Stobbe: >> Yes, the short hand I like to use is 4 nV*sqrt(R/1000). >> >> 2 nV/rthz off a bandgap is pretty darn impressive, that includes a delta >> vbe gained up ~10x. > >Methinks the advantage comes from

Re: [time-nuts] Totally unrelated, but..

...@megapathdsl.net Subject: Re: [time-nuts] Totally unrelated, but.. kb...@n1k.org said: >> the cool thing about those parts is that their PSRR extends up to >> several MHz. A lot of LDOs have good PSRR to kHz. > Which to bring it back to noise in radios ….. cou

Re: [time-nuts] Totally unrelated, but..

; is, to see if there was some very narrow band of sensitivity. > Nothing. > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim > Sent: Wednesday, December 7, 2016 12:31 PM > To: time-nuts@febo.com > Subject: Re: [time-nuts

Re: [time-nuts] Totally unrelated, but..

In message , "Van Horn, David" writes: >I did check the circuit through the whole range that it should >operate in, based on component data sheets. No issues. How long are the wires supplying the regulator

Re: [time-nuts] Totally unrelated, but..

- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Joe Leikhim Sent: Wednesday, December 7, 2016 12:31 PM To: time-nuts@febo.com Subject: Re: [time-nuts] Totally unrelated, but.. Could the low noise parts actually be counterfeit, relabeled as such? Is the circuit the regulator feeds

Re: [time-nuts] Totally unrelated, but..

Ed wrote: It would be helpful to give some specific info about the circuit and regulators used for these experiments, such as operating voltage, load current, and regulator type. I concur. It would also be helpful to have more detail about the phenomenon you are observing (see below).

Re: [time-nuts] Totally unrelated, but..

That's a really nice part, like the old LM723 was bring your own pass element, the 3042 is essentially bring your own reference, I hope that is a trend that continues. And a 10uF capacitor is pretty quiet at 1KHz plus. The other neat thing about the 3042 is the error amplifier is run unity gain

Re: [time-nuts] Totally unrelated, but..

Of Chuck Harris Sent: Wednesday, December 7, 2016 1:57 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. I don't think so. I first ran into a batch of LM340-5's that were excellent oscillators back in the 1970's... long before

Re: [time-nuts] Totally unrelated, but..

On 12/7/16 9:34 PM, Hal Murray wrote: kb...@n1k.org said: the cool thing about those parts is that their PSRR extends up to several MHz. A lot of LDOs have good PSRR to kHz. Which to bring it back to noise in radios ….. could be the issue there. The device isn’t oscillating, it’s just

Re: [time-nuts] Totally unrelated, but..

It would be helpful to give some specific info about the circuit and regulators used for these experiments, such as operating voltage, load current, and regulator type. I may have missed some points in the discussion on this, but I think the following things are the case: 1. The circuit

Re: [time-nuts] Totally unrelated, but..

Hi The problem with a “simple” filter is that they rarely work as well as you might think they do. Grounding and other layout issues generally get you sooner than you would think. Coils and caps are often not as broadband as you would hope…. Bob > On Dec 8, 2016, at 12:34 AM, Hal Murray

Re: [time-nuts] Totally unrelated, but..

kb...@n1k.org said: >> the cool thing about those parts is that their PSRR extends >> up to several MHz. A lot of LDOs have good PSRR to kHz. > Which to bring it back to noise in radios ….. could be the issue there. The > device isn’t oscillating, it’s just not blocking the crud from

Re: [time-nuts] Totally unrelated, but..

Hi > On Dec 7, 2016, at 11:36 PM, jimlux wrote: > > On 12/7/16 4:20 PM, Scott Stobbe wrote: >> Yes, the short hand I like to use is 4 nV*sqrt(R/1000). >> >> 2 nV/rthz off a bandgap is pretty darn impressive, that includes a delta >> vbe gained up ~10x. >> >> On Wed, Dec

Re: [time-nuts] Totally unrelated, but..

On 12/7/16 4:20 PM, Scott Stobbe wrote: Yes, the short hand I like to use is 4 nV*sqrt(R/1000). 2 nV/rthz off a bandgap is pretty darn impressive, that includes a delta vbe gained up ~10x. On Wed, Dec 7, 2016 at 7:03 PM Bob Camp wrote: H the cool thing about those parts is

Re: [time-nuts] Totally unrelated, but..

Yes, the very low frequency noise of these regulators isn't anywhere near as impressive as their high frequency noise.However for some RF circuits the low frequency power supply noise may not be as significant as other effects. Bruce   On Thursday, 8 December 2016 2:59 PM, Gerhard Hoffmann

Re: [time-nuts] Totally unrelated, but..

Am 08.12.2016 um 01:20 schrieb Scott Stobbe: Yes, the short hand I like to use is 4 nV*sqrt(R/1000). 2 nV/rthz off a bandgap is pretty darn impressive, that includes a delta vbe gained up ~10x. Methinks the advantage comes from converting their reference (whatever that may be) to a really

Re: [time-nuts] Totally unrelated, but..

Am 08.12.2016 um 00:50 schrieb jimlux: On 12/7/16 3:32 PM, Richard (Rick) Karlquist wrote: On 12/7/2016 12:16 PM, Clint Jay wrote: I was looking for a low noise regulator to power a log amp/detector earlier this year and was rather surprised to find the 78xx regulators were considerably better

Re: [time-nuts] Totally unrelated, but..

> > >> > > >> > > >> Fortunately this isn't a critical piece of equipment, but I want it > > >> working RIGHT before I put it back in service. > > >> > > >> It's a custom receiver for 457 kHz. > > >> >

Re: [time-nuts] Totally unrelated, but..

I've no doubt there are many excellent low noise regulators out there that are orders of magnitude better than the 78xx series, but there are also many that claim low noise as a headline feature and are actually worse when you dig into the specification. On 7 Dec 2016 23:42, "Richard (Rick)

Re: [time-nuts] Totally unrelated, but..

>> -Original Message- >> >> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Graham / >> KE9H >> >> Sent: Wednesday, December 7, 2016 10:41 AM >> >> To: Discussion of precise time and frequency measurement >> >> Subject:

Re: [time-nuts] Totally unrelated, but..

> > Sent: Wednesday, December 7, 2016 10:41 AM > > To: Discussion of precise time and frequency measurement > > Subject: Re: [time-nuts] Totally unrelated, but.. > > > > Remember that the internal Voltage reference in the original three > terminal regulator desig

Re: [time-nuts] Totally unrelated, but..

Hi You can indeed find regulators with noise densities that work out to be uV/sqrt(Hz) advertised as “low noise”. Who knows how marketing justified making the claim other than “not as totally rotten as our older part”. Bob > On Dec 7, 2016, at 6:32 PM, Richard (Rick) Karlquist

Re: [time-nuts] Totally unrelated, but..

On 12/7/16 3:32 PM, Richard (Rick) Karlquist wrote: On 12/7/2016 12:16 PM, Clint Jay wrote: I was looking for a low noise regulator to power a log amp/detector earlier this year and was rather surprised to find the 78xx regulators were considerably better than many of the "low noise" devices.

Re: [time-nuts] Totally unrelated, but..

On 12/7/2016 12:16 PM, Clint Jay wrote: I was looking for a low noise regulator to power a log amp/detector earlier this year and was rather surprised to find the 78xx regulators were considerably better than many of the "low noise" devices. Are you kidding me? Check out the Linear

Re: [time-nuts] Totally unrelated, but..

I don't think so. I first ran into a batch of LM340-5's that were excellent oscillators back in the 1970's... long before counterfeiting was even remotely possible. The symptom is the regulator puts out only 4.5 out of 5V. LM309's were, however, totally immune. Usually, I had to be really bad

Re: [time-nuts] Totally unrelated, but..

Hi There are a *bunch* of people making stuff like 78xx regulators. Even 20 years ago, there was a lot of difference between brand M, brand T, and brand F on these devices. Today the spread is even larger. Toss in outfits that sub contract the work to who knows where this week …. What you get

Re: [time-nuts] Totally unrelated, but..

I was looking for a low noise regulator to power a log amp/detector earlier this year and was rather surprised to find the 78xx regulators were considerably better than many of the "low noise" devices. But!! I've also had odd experiences with some brands of 78xx devices (and way before the 'net

Re: [time-nuts] Totally unrelated, but..

Could the low noise parts actually be counterfeit, relabeled as such? Is the circuit the regulator feeds sensitive to a narrow band of voltage that the "good regulator" is outside of? Try replacing the regulator with a battery supply and resistor divider to attain the working voltage. Move

Re: [time-nuts] Totally unrelated, but..

Of Graham / KE9H Sent: Wednesday, December 7, 2016 10:41 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. Remember that the internal Voltage reference in the original three terminal regulator designs is a Zener. (Zeners are also useful

Re: [time-nuts] Totally unrelated, but..

The probes don't seem to affect anything. -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Andy Sent: Wednesday, December 7, 2016 7:56 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. >

Re: [time-nuts] Totally unrelated, but..

ysteries. > > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp > Sent: Wednesday, December 7, 2016 9:43 AM > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] Totally unrelated, but.. > > H

Re: [time-nuts] Totally unrelated, but..

Once upon the time, there were some "three legged" voltage regulators, which were very sensitive to the ESR value of the capacitor which was connected to their output. With to low ESR values they oscillated, [the oscillation was "inside" of the regulator, which became warm, or sometimes hot,

Re: [time-nuts] Totally unrelated, but..

- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp Sent: Wednesday, December 7, 2016 9:43 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Totally unrelated, but.. Hi You probably have proven one of the most basic design truths: Parts

Re: [time-nuts] Totally unrelated, but..

Remember that the internal Voltage reference in the original three terminal regulator designs is a Zener. (Zeners are also useful as RF white noise sources.) The regulator is generally an amplifier with DC feedback. If you look at the application notes on the early regulators, they require

Re: [time-nuts] Totally unrelated, but..

Hi You probably have proven one of the most basic design truths: Parts will *always* oscillate just outside the bandwidth of your test gear” :). A few other possible issues: 1) Something else is oscillating and it is simply interacting with the regulator in an odd way. 2) The oscillation /

Re: [time-nuts] Totally unrelated, but..

> > I looked at the reg input and output with scope and spectrum analyzer, and > I don't see anything that indicates excessive noise or oscillation. > Does the receiver's noise persist with the scope or spectrum analyzer attached? Connecting their probes might temporarily "fix" the problem so

Re: [time-nuts] Totally unrelated, but..

Is part of the problem that the level of noise that is of concern is below what a scope can see anyway: PPB? If the noise is not narrow band it might also be not observable using a spectrum analyzer? Pete. On 12/7/2016 4:09 AM, Poul-Henning Kamp wrote: In message

Re: [time-nuts] Totally unrelated, but..

In message , "Van Horn, David" writes: >So what is it that a monolithic regulator (linear) can do which >is not observable on a scope or SA, which would cause a receiver >to think it's getting a signal or

[time-nuts] Totally unrelated, but..

Lots of discussion on here about low noise regulation so someone may know what to look for. I have a receiver which is getting a lot of interference from somewhere. Antenna disconnected, interference still high. After much poking around, we found that replacing a voltage regulator with a