Re: [time-nuts] High-end GPSDO's

On Sun, 19 Aug 2018 15:27:03 -0700 Ralph Devoe wrote: > Thanks for the notes on the FS740. I missed it back last November. It > looks so user-friendly that I might have to get one. Most SRS stuff is > really well done. Yes, indeed. All SRS schematics I have read looked really like someone who

[time-nuts] High-end GPSDO's

Thanks for the notes on the FS740. I missed it back last November. It looks so user-friendly that I might have to get one. Most SRS stuff is really well done. The question I have is whether it is practical to get to the 10(-13) level with a good Rb and a good GPSDO. The Rb's aging rate is low

Re: [time-nuts] Choosing a GPS IC for carrier phase measurements

Hi > On Aug 19, 2018, at 5:26 PM, Nicolas Braud-Santoni > wrote: > > On Sat, Aug 18, 2018 at 08:25:11PM +0200, Attila Kinali wrote: >> On Thu, 16 Aug 2018 17:45:30 +0200 >> Nicolas Braud-Santoni wrote: >> >>> The main issue I'm running into is that most timing GPS modules will >>> happily

Re: [time-nuts] Choosing a GPS IC for carrier phase measurements

On Sat, Aug 18, 2018 at 10:13:49PM +0200, Magnus Danielson wrote: > >> 2) replace the internal oscillator with one phase locked to your OCXO. > >> [...] > > > > If you go this route, the close in phase noise of your signal needs to be > > in the > > “pretty good TCXO” range. There are indeed

Re: [time-nuts] Choosing a GPS IC for carrier phase measurements

On Sat, Aug 18, 2018 at 08:25:11PM +0200, Attila Kinali wrote: > On Thu, 16 Aug 2018 17:45:30 +0200 > Nicolas Braud-Santoni wrote: > > > The main issue I'm running into is that most timing GPS modules will > > happily give you carrier phase measurements... for their internal > > oscillator, and

Re: [time-nuts] History Channel "In Search of" Time Travel

In the UK, www.history.com forcibly redirects to www.history.co.uk On Sun, Aug 19, 2018 at 1:44 PM, Didier Juges wrote: > That would be very nice since I missed it. > Thanks in advance, > Didier KO4BB > > On Sat, Aug 18, 2018, 2:24 PM Dan Rae wrote: > > > If anyone wants to see this I could

Re: [time-nuts] TNS-BUF update

Without the benefit of agressive low pass filtering the noise of an LT3042 at 10Hz is at least an order of magnitude worse than that of an unfiltered LED for the same output voltage. The noise of Nitride passivated LEDs degrades significantly with aging and there is a strong correlation between

Re: [time-nuts] TNS-BUF update

There are some NIR sensitive photodiodes that take advantage of the NIR transparency of some black epoxies. Bruce > On 20 August 2018 at 02:48 Dana Whitlow wrote: > > > Be watchful about the black epoxy. It may just be a dyed (otherwise > clear) epoxy, > and some of the black dyes in common

Re: [time-nuts] High-end GPSDO's

On Sat, 18 Aug 2018 20:53:19 +0200 Attila Kinali wrote: > Just to avoid confusion: I don't want to bash the FS740, not at all. > It's a very well designed device with lots of ingenious solutions for > small details (see also my quick review of it at [2]), but it's still > just a GPSDO and has to

[time-nuts] TNS-BUF update

Also check your red LEDs. I have some that have a Vf of over 3V. They could be a blue LED/phosphor (not likely, blue -> red conversion is rather inefficient) or two red LEDs in series. ___ time-nuts mailing list -- time-nuts@lists.febo.com To

Re: [time-nuts] TNS-BUF update

Am 19.08.2018 um 14:43 schrieb Bruce Griffiths: Yes, I looked at the plots and I see exactly what I described. 2nV/rtHz at frequencies somewhat above the reference current source output RC filter, rising to a high value at frequencies below the current source output filter pole. This is an

Re: [time-nuts] TNS-BUF update

Be watchful about the black epoxy. It may just be a dyed (otherwise clear) epoxy, and some of the black dyes in common use pass near IR quite readily. This would probably be most troublesome if the ambient light source were of the incandescent persuasion. Also, small diodes in clear packages

Re: [time-nuts] TNS-BUF update

That's a very good point. I have used LEDs as photocells many times, the first time was in 1974 when it was easier for this university student to get LEDs than photocells. I have also made a bi-directional optically isolated data link using a single fiber optic cable and two fiber optic

Re: [time-nuts] TNS-BUF update

Yes, I looked at the plots and I see exactly what I described. 2nV/rtHz at frequencies somewhat above the reference current source output RC filter, rising to a high value at frequencies below the current source output filter pole. This is an inherent property of the architecture. The LT3042 is

Re: [time-nuts] TNS-BUF update

Am 19.08.2018 um 10:22 schrieb Bruce Griffiths: Rick I devised the bias circuit for the TNS-BUF. It exploits the fact that for a RED LED at least the difference between the LED forward voltage and the transistor Vbe is ~ 1V and has a fairly low tempco and has low noise (at least for RED