Re: [time-nuts] Cold Rubidium?

On Sun, Nov 3, 2019 at 7:04 PM Attila Kinali wrote: > Though, the cost is lower. Low enough that I would choose one of > these instead of buying a 5071. My google sleuthing indicates that they're selling it for about $347k:

Re: [time-nuts] Dead 5061B

Jim Is there any hope. I would believe so. CS tubes are pretty tough. As Scott says HV supplies but you measured those and they appear good as you say. So its a knock down drag out battle. You have nothing to loose so dig in. I wonder if the SRD may have popped. But its funny the ion pump is 0.

[time-nuts] help understanding drift in two ptpd-synchronized systems

Good afternoon, everyone, Thanks to some helpful souls here, I have ptpd-2.0.0 running on a number of STM32F7 dev boards. I’ve got them configured to emit the 125ms PPS pulse and using a logic analyzer or scope with persistence on, I can see that the PPS rising edges are able to stay within a

Re: [time-nuts] A simple sampling DMTD

Hi Yes, it only will be fully correlated well inside the loop bandwidth. The loop bandwidth normally used for this sort of thing is >> 1 Hz. By the time you start doing ADEV, you are in the correlated region. Bob > On Nov 3, 2019, at 3:42 PM, Jan-Derk Bakker wrote: > > Hi Bob, > >> If you

Re: [time-nuts] Cold Rubidium?

On Sun, 03 Nov 2019 21:56:38 + "Poul-Henning Kamp" wrote: > Not _quite_ a DIY project yet, but certainly easier than a fountain... Not by much, though. In terms of infrastructure you need, you are pretty close to a fountain: Advanced laser system with multiple frequencyies locked to an

Re: [time-nuts] A simple sampling DMTD

Dear Attila, > The test was run for 175k seconds (just over 2 days) in a very much > > non-temperature controlled attic. The resulting ADEV can be found at > > http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20ADEV.pdf ; the > > This looks good, but I would still expect the start of the ADEV

Re: [time-nuts] Cold Rubidium?

In message <20191103191220.eb7af29b45fdaf77f2fa4...@kinali.ch>, Attila Kinali writes: Not _quite_ a DIY project yet, but certainly easier than a fountain... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer

Re: [time-nuts] Raspberry Pi TCXO Hat

On Sat, November 2, 2019 6:37 am, Adrian Godwin wrote: > Also - I'm unsure of the benefit of having a TCXO for the ethernet clock Would only be of benefit if using an Ethernet device which timestamps IEEE 1588 packets with the clock running in the NIC. Typical usage on a linux based system

Re: [time-nuts] A simple sampling DMTD

Hi Bob, > If you phase lock the downconversion reference, the VCXO noise that now is uncorrelated > between the channels will become correlated. That may make things worse rather > than better Does the impact not depend on the loop bandwidth and VCXO performance? If I read it correctly, in

Re: [time-nuts] Dead 5061B

Have you checked the HV supplies? Content by Scott Typos by Siri > On Nov 3, 2019, at 2:04 PM, AC0XU (Jim) wrote: > Time Nuts- This 5061B was working fine until a recent power failure, after which the unit would not come on line (alarm light stayed lit). Major symptoms now: Beam I ;

Re: [time-nuts] Question for my new GPSDO

ed breya writes: > I think the main need for the overall DAC system in these is not > linearity, but monotonicity - an increasing digital input always > causes an output change in one direction only, and never reverses. An y=x³ (cubic) transfer function is monotonic but not linear, yet you

[time-nuts] Dead 5061B

Time Nuts- This 5061B was working fine until a recent power failure, after which the unit would not come on line (alarm light stayed lit). Major symptoms now: Beam I ; Second Harmonic; Ion Pump Supply are all 0 on front panel. All other front panel readings are normal. (except for

Re: [time-nuts] Question for my new GPSDO

I think the main need for the overall DAC system in these is not linearity, but monotonicity - an increasing digital input always causes an output change in one direction only, and never reverses. The linearity and other characteristics of the sub-parts comes into play when you need to combine

Re: [time-nuts] A simple sampling DMTD

On Sun, 3 Nov 2019 01:41:08 +0100 Jan-Derk Bakker wrote: > The test was run for 175k seconds (just over 2 days) in a very much > non-temperature controlled attic. The resulting ADEV can be found at > http://www.lartmaker.nl/time-nuts/DMTD%20self-noise%20ADEV.pdf ; the This looks good, but I

Re: [time-nuts] Cold Rubidium?

Moin, On Fri, 25 Oct 2019 09:32:59 -0600 "AC0XU (Jim)" wrote: > Does anyone have any experience/first hand knowledge of this Cold Rubidium > standard? > > https://spectradynamics.com/products/crb-clock/ > > The specs look very good. The mfr

Re: [time-nuts] GPSDO+PC as a NTP server

On Wed, 23 Oct 2019 12:37:24 -0700 Fiorenzo Cattaneo wrote: > GPS and GLONASS are the best GNSS around, they are operated by the > military as a military operation and have the best reliability record. > Beidu is fairly new, and Galileo is operated by civlian agencies. > They've had major

Re: [time-nuts] Question for my new GPSDO

Attila Kinali writes: > There is, as far as I know, only two types of DA converters that > are inherently linear: single-bit delta-sigma modulators and > Kelvin-Varley dividers. No, the Kelvin-Varley is not guaranteed to be linear, same story as a string DAC actually. Whether a delta-sigma

Re: [time-nuts] Question for my new GPSDO

Hoi Tobias, On Wed, 16 Oct 2019 16:30:19 + Tobias Pluess wrote: > I attached my own schematics of the EFC control circuit. I think with this > circuit, it should be possible to achieve a similar resolution as you > mentioned in your thoughts. > > D3 is a 16bit resistor string DAC and

Re: [time-nuts] Question for my new GPSDO

Hi Stepping back a bit here ….. All oscillators have phase noise. It’s going to vary with the offset from carrier. What you get at 10KHz will be much better than what you get at 1Hz. As long as the EFC does not make this any worse, there is no need to get very crazy. Putting the added noise 40

Re: [time-nuts] Used ESE ES-911/GPS/NTP Master Time Clock

CONGRATS. I was trying to understand how the MSC51 processor could have failed, but the Motorola M12 receiver was functional. The ML621 sold as solder-tab or coin version (for socket). ~ $2.00 each. My Harbor Freight Digital Caliper uses the ML621 coin cell size (as well as my 1980s HP

Re: [time-nuts] can of worms: time-of-day in a community radio station

On Sat, 19 Oct 2019 18:24:57 -0700 Fiorenzo Cattaneo wrote: > The main reason I do not trust "pool" servers is because there is no > guarantee of which server you will get. I might be paranoid, but I am > worried about rogue servers, and I much rather trust well known public > stratum-1 NTP

Re: [time-nuts] GPS SV74/PRN04 now trackable...

Tracking it on L1C/A, L1P(Y), L2C and L2P(Y) here on a Septentrio PolaRX4TR - no L5-capable antenna, so nothing on L5, though. As you say, marked as unhealthy. Ole -Opprinnelig melding- Fra: time-nuts På vegne av J Grizzard Sendt: søndag 3. november 2019 04:01 Til:

Re: [time-nuts] A simple sampling DMTD

Hi > On Nov 2, 2019, at 8:41 PM, Jan-Derk Bakker wrote: > > Dear all, > > Attila got me thinking with his remark: > > I am a bit astonished by the high noise level you have. I would have >> expected >> this to yield something below 1ps, judging from what we got from what >> Nicolas >>

Re: [time-nuts] Question for my new GPSDO

On Mon, 14 Oct 2019 20:46:14 + Tobias Pluess wrote: > For sure the 1PPS output will be generated in hardware. I have made good > experiences with using a microcontroller timer: One can use an ordinary PWM > channel and this generates very precise pulses, and no interrupts or the > like

Re: [time-nuts] Question for my new GPSDO

Hoi Tobias, On Mon, 14 Oct 2019 11:49:29 + Tobias Pluess wrote: > I have now designed the EFC circuit such that it is easily possible to use > different DAC and voltage reference models. I have also reverse-engineered > the circuit which is used on the Oscilloquartz GPSDO. They seem to

[time-nuts] Used ESE ES-911/GPS/NTP Master Time Clock

I got my ESE ES-911 to work.The problem that I was seeing was that the unit was not seeing data from the GPS receiver... it would not show a GPS lock, even though the GPS receiver (a Motorola M12+) was working properly.Probing around the ESE motherboard showed the GPS receiver was not