Re: [time-nuts] Effect of EFC noise on phase noise

Am 02.08.2016 um 02:42 schrieb Bruce Griffiths: /"I'm working on a new amplifier based on IF3602 or BF862 FETs that can use 10u foil only."/ / / Similar to that published by Groner in Linear Audio? / / I know that Groner exists from some web site, but had no personal contact. Also I don't read

Re: [time-nuts] Effect of EFC noise on phase noise

"I'm working on a new amplifier based on IF3602 or BF862 FETs that can use 10u foil only." Similar to that published by Groner in Linear Audio? Bruce On Tuesday, 2 August 2016 12:12 PM, Gerhard Hoffmann wrote: Am 01.08.2016 um 22:16 schrieb David: > This duplicates the

Re: [time-nuts] Effect of EFC noise on phase noise

davidwh...@gmail.com said: > I always thought they should bring the varactor or EFC ground out as a > separate pin but I assume that since they do not, ground noise at least > within the oscillator does not limit performance. I'm pretty sure I've seen comments, probably on this list, about

Re: [time-nuts] Effect of EFC noise on phase noise

Hi Ultimately the EFC signal gets to one or more varicap diodes. It likely goes through a bias or attenuator network to get there. Playing with the resistors in the network allows the manufacturer to produce parts with consistent EFC properties. The pinout of your standard OCXO and it’s single

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

> On Aug 1, 2016, at 9:33 AM, Chris Albertson wrote: > > > > In fact that would be a good experiment: Put two clocks up on a large > computer monitor and make one always tick some random number of > milliseconds away from system time and the other always thick on

Re: [time-nuts] Effect of EFC noise on phase noise

Are the EFC inputs all directly DC coupled to the varactor diodes making them high DC impedance? I always thought they should bring the varactor or EFC ground out as a separate pin but I assume that since they do not, ground noise at least within the oscillator does not limit performance. In the

Re: [time-nuts] Effect of EFC noise on phase noise

Am 01.08.2016 um 22:16 schrieb David: This duplicates the problems encountered when trying to quantify low frequency noise from a voltage reference; it is difficult to make an low frequency high pass filter with lower noise than the lowest noise references and the capacitor is the problem. I beg

Re: [time-nuts] Effect of EFC noise on phase noise

Yep, it supports the big C (padded out with increasingly smaller caps) in general wins. For two low pass filters, one with say 100nF and one with 10nF, same fc, the 100nF filter will have 10 times less noise power, or sqrt(10) less rms noise. Near DC is another story. On Mon, Aug 1, 2016 at 5:10

Re: [time-nuts] Effect of EFC noise on phase noise

With my filter , I had good success and 5 K is not too high , Ulrich Sent from my iPhone > On Aug 1, 2016, at 11:46 AM, Bob Camp wrote: > > Hi > > ….. until you discover that you picked the *wrong* capacitor manufacturer and > you have > more noise from leakage in the cap

Re: [time-nuts] Effect of EFC noise on phase noise

HI Broadband is not where you run into the trouble on any of these circuits. It’s always what happens within a decade or two past cutoff or inside the pass band. Bob > On Aug 1, 2016, at 4:50 PM, Scott Stobbe wrote: > > The broadband thermal noise at a circuit

Re: [time-nuts] Q/noise of Earth as an oscillator

A bit short on the phone... Both the ECI and ECEF frames are rotating at sidreal rate. The earth rate is (a small) part of the navigation equations. Thus its needed in inertial nav. Glenn, look at the performance of the big land RLGs - NZ and German that were linked last week. How much better

Re: [time-nuts] Effect of EFC noise on phase noise

The broadband thermal noise at a circuit point with a cap is always kT/c On Monday, 1 August 2016, Bob Camp wrote: > Hi > > If you wire up all the possible circuits and check them all out … the > answer is that big C / small R wins. Big R gets you into resistor noise > issues >

Re: [time-nuts] Effect of EFC noise on phase noise

Hi If you are in the region that a low noise reference will apply to a low deviation precision standard, you are deep into “small angle” territory. The higher order stuff simply does not apply. Rotate the spectrum by 1/f (FM -> PM) and calculate the level at 1 Hz …..end of story. If when you

Re: [time-nuts] Effect of EFC noise on phase noise

Hi If you wire up all the possible circuits and check them all out … the answer is that big C / small R wins. Big R gets you into resistor noise issues and stray pickup. Bob > On Aug 1, 2016, at 4:16 PM, David wrote: > > This duplicates the problems encountered when

Re: [time-nuts] Effect of EFC noise on phase noise

This duplicates the problems encountered when trying to quantify low frequency noise from a voltage reference; it is difficult to make an low frequency high pass filter with lower noise than the lowest noise references and the capacitor is the problem. In Linear Technology Application Note 124,

Re: [time-nuts] Effect of EFC noise on phase noise

I don't have the answer of the top of my head, but phase noise of VCOs and PLLs is well documented. Perhaps "loop filter noise vco" or the like may help. On Mon, Aug 1, 2016 at 11:18 AM, Attila Kinali wrote: > On Mon, 01 Aug 2016 14:36:28 + > "Poul-Henning Kamp"

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

Yo Mark! On Sat, 30 Jul 2016 20:14:02 + Mark Sims wrote: > A couple of people have asked about the poor message arrival time > performance of the popular Adafruit Ultimate GPS receiver. I have several months of Adafruit graphs. I also find that is is usually as

Re: [time-nuts] Effect of EFC noise on phase noise

On 8/1/16 8:18 AM, Attila Kinali wrote: On Mon, 01 Aug 2016 14:36:28 + "Poul-Henning Kamp" wrote: I need some formulas that relate EFC noise to the (added) phase noise of an OCXO. It shouldn't be too difficult to come up with something. But before I make some stupid

Re: [time-nuts] Q/noise of Earth as an oscillator

glennmaill...@bellsouth.net said: > In navigation we used the earth rate of 15.04 degrees per hour. This was > treated as a 'constant' even though it varied with wind, waves on the ocean > and other things affecting the instantaneous rotational speed of the earth. Were the wind and waves and

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

HI You very much are not *done* when you get your point at a million seconds. That’s just where you get to *start* …. Since you are talking about nearly two weeks per sample, there are a *lot* of things that could happen. If your loop needs ten samples to do much with, it will be 4 months

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi Glenn, Your 15.04 number rings a bell [1]. The conventional solar day is simply 86400 seconds (24 hours). So each hour is 15 degrees, exactly. But the actual (sidereal) earth rotation rate is about 86164 SI seconds (23h 56m 4.091s). So each hour is 15.0411 degrees. Someone who understands

Re: [time-nuts] Q/noise of Earth as an oscillator

In navigation we used the earth rate of 15.04 degrees per hour. This was treated as a 'constant' even though it varied with wind, waves on the ocean and other things affecting the instantaneous rotational speed of the earth. How does this factor into leap seconds, or, does it? We accept that

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

From: Mark Sims Well, the whole point of the exercise is to see how well you can do if you DON'T have an internet connection, a 1PPS signal, or a stratum 1 time server available... only the humble messages coming from a 10 dollar GPS receiver. Try getting a net connection in the middle of

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

Hi The issue with any of these approaches is how long it will take to converge. If I start with a pps that is good to 10 ns and my goal is 10 ns or 10 ppb, I’m there in a second. If I start with a serial string that is good to 10ms and my goal is 10 ppb, I’m waiting for a million seconds per

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

As an exercise it might be fun to try to do the best you can with just NMEA. But practically speaking even my very $10, 8-channel motorola GPS receiver can output a PPS to about 50ns. Better then needed for NTP. You friend in the Gobi desert would be better off my $10 GPS That said, if you

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

You are right. NTP, even over a poor internet connection can typically do better then the tens milliseconds we see with some NEMA GPS'. But you eyes and human perfection is still even worse. You can't notice 40mS of error. In fact that would be a good experiment: Put two clocks up on a large

[time-nuts] Adafruit Ultimate GPS timing message arrival times

Well, the whole point of the exercise is to see how well you can do if you DON'T have an internet connection, a 1PPS signal, or a stratum 1 time server available... only the humble messages coming from a 10 dollar GPS receiver. Try getting a net connection in the middle of the Gobi desert

Re: [time-nuts] Effect of EFC noise on phase noise

On Mon, 1 Aug 2016 11:21:10 -0400 KA2WEU--- via time-nuts wrote: > A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans > many things Uhmm.. with 1mF in capacitors... don't you run into into microphonics problems? Or all these capacitors supposed to

Re: [time-nuts] Effect of EFC noise on phase noise

Hi ….. until you discover that you picked the *wrong* capacitor manufacturer and you have more noise from leakage in the cap than you did to start out with :) In general “big C and small R” is the better solution than “big R and small C”. The pesky part is that with electrolytic caps, the

Re: [time-nuts] Effect of EFC noise on phase noise

A good filter in the cable is highly recommended, 5 KOhm & 1000 uF cleans many things In a message dated 8/1/2016 11:12:51 A.M. Eastern Daylight Time, kb...@n1k.org writes: Hi It’s just very standard FM modulation math. The only gotcha is the (often unknown) bandwidth of the EFC port.

Re: [time-nuts] Q/noise of Earth as an oscillator

Hi Jim. > You said: "you need energy; you need energy loss; you need cycles over which > that loss repeatedly occurs." > With regard to the earth, where is the first one? By first one, do you mean where does the initial energy come from? For a pendulum clock, you supply energy with a lift or a

Re: [time-nuts] Effect of EFC noise on phase noise

On Mon, 01 Aug 2016 14:36:28 + "Poul-Henning Kamp" wrote: > >I need some formulas that relate EFC noise to the (added) phase noise of > >an OCXO. It shouldn't be too difficult to come up with something. But > >before I make some stupid mistakes, i wanted to ask whether

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

On Mon, Aug 1, 2016 at 3:01 AM, Hal Murray wrote: > Depends on your internet connection and/or the specific GPS module you are > using. > > I don't know of any good GPS modules that use NMEA. I do know of really > crappy internet connections. Bufferbloat is the

Re: [time-nuts] Effect of EFC noise on phase noise

Hi It’s just very standard FM modulation math. The only gotcha is the (often unknown) bandwidth of the EFC port. Even on a precision OCXO, it might be <10 Hz, it might be over a KHz …. The trap many fall into is the “small angle” restriction. You can get into modulation indexes that will get

Re: [time-nuts] Effect of EFC noise on phase noise

In message <20160801154643.905ed816ac900a8d9a505...@kinali.ch>, Attila Kinali w rites: >I need some formulas that relate EFC noise to the (added) phase noise of >an OCXO. It shouldn't be too difficult to come up with something. But >before I make some stupid mistakes, i wanted to ask

[time-nuts] Effect of EFC noise on phase noise

Moin, I need some formulas that relate EFC noise to the (added) phase noise of an OCXO. It shouldn't be too difficult to come up with something. But before I make some stupid mistakes, i wanted to ask whether someone has already done this or has any references to papers? My google-foo was not

Re: [time-nuts] Very Accurate Delta Time RF Pulse Measurements

Have you looked at the blitzortung.org system? There may be some ideas to glean from that On July 28, 2016 6:12:54 PM CDT, Jerome Blaha wrote: >Hi Guys, > >This is a little outside of time-nuts scope, but not by much. I'm >interested in finding the time between two

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

david-tay...@blueyonder.co.uk said: > From your data and my own measurements, I feel that using the serial NMEA > stream would, today, be a last resort, as an Internet sync would be > considerably better. Would you agree with that? Depends on your internet connection and/or the specific GPS

[time-nuts] Adafruit Ultimate GPS timing message arrival times

Yes, I find it confusing also. I've been reporting the value that Lady Heather uses to do most of her evil internal message off machinations with... For those, the negative offset value is the "natural" polarity. I'm probably going to change it around to something humans (including me)

Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times

From: Mark Sims As mentioned in the post the times reported are the time stamp in the receiver packet minus the system clock time when it was received... negative value indicate the message arrives after the PPS. The polarity of the reported value is consistent with how Lady Heather makes