Re: [time-nuts] Noise Floor

> Is there a _done_ solution to expand a Timepod to > ~ 100 MHz, narrow-bandish is OK. I'm willing to solder, > but I'm not ready for yet another development project. > Not now. A pair of double-balanced mixers driven by independent signal generators works well. The mixer RF inputs are driven by

Re: [time-nuts] Noise Floor

Hi > On Mar 24, 2020, at 7:31 PM, jimlux wrote: > > On 3/24/20 2:17 PM, John Miles wrote: It would be interesting to know what ADC was used and if there's an SDR-board out there that uses the same ADC. >>> >>> Uh.. I remember John telling me what ADC it was, but I forgot, sorry. >> It

Re: [time-nuts] Noise Floor

> And then, getting the data reliably out of the ADC into the FPGA, and > synchronized across multiple channels. That particular part doesn't > guarantee the startup state of the internal pipeline. There's a sync pin for use with the clock divider, but AFAIK it does nothing when the divider isn't

Re: [time-nuts] Mains frequency data for Europe

The entsoe.eu site is full of 404... the only site I can find with frequency data is this (for the Belgian grid): What happened to the grid frequency in Europe in Jan 2019 and Apr 2019:

[time-nuts] Symmetricom analog network clocks.

Some years ago, symmetricom sold out some analog network clocks. Last winter, both of mine froze up and would not adjust. Being naturally curious, I opened one up, and found the motor and wheels that drive the hands. Knowing that this type of motor has problems, I simply unplugged it and manual

Re: [time-nuts] Noise Floor

On 3/24/20 2:17 PM, John Miles wrote: It would be interesting to know what ADC was used and if there's an SDR-board out there that uses the same ADC. Uh.. I remember John telling me what ADC it was, but I forgot, sorry. It uses four AD9265s. The TimePod used four LTC2216s, but the AD9265s su

Re: [time-nuts] Mains frequency data for Europe

Hello Attila, In principle I have that data (I've been logging the grid's phase since 2008), but I'll need to do a bit of work to extract it to a usable format. Please contact me off-list. Regards, Pieter-Tjerk On Tue, Mar 24, 2020 at 04:30:25PM +0100, Attila Kinali wrote: > Hi, > > Does som

Re: [time-nuts] Noise Floor

Am 24.03.20 um 20:06 schrieb Attila Kinali: If you want an SDR like system to play with, try the Red Pitaya? You get 2 ADC channels 125MHz/14Bit or 128.x MHz/16 Bit, 2 DAC channels, 2 ARM CPUs, Network etc and it boots Linux when you plug in an USB power supply. It has existing apps such as

Re: [time-nuts] Noise Floor

> > It would be interesting to know what ADC was used and if there's an > > SDR-board out there that uses the same ADC. > > Uh.. I remember John telling me what ADC it was, but I forgot, sorry. It uses four AD9265s. The TimePod used four LTC2216s, but the AD9265s support higher clock rates with

Re: [time-nuts] Noise Floor

On Tue, 24 Mar 2020 18:26:28 +0200 Anders Wallin wrote: > It would be interesting to know what ADC was used and if there's an > SDR-board out there that uses the same ADC. > Our experience with the Ettus radios is that although they have 2 channels > there is a lot of cross-talk between rx1 and r

Re: [time-nuts] weird Raspberry PPS+GPS NTP server behaviour

Folks, Thanks for all the help. I've put up a simple Web page showing the program and its results here: https://www.satsignal.eu/ntp/Raspberry-Pi-ntpheat.html A good gain on that Raspberry Pi in a centrally heated room and nearer the radiator than it should be. Cheers, David -- SatSignal

Re: [time-nuts] Noise Floor

Hi Since the unit is still in warranty, I’m a bit hesitant to crack it open and start poking around :). While it’s not 100% obvious, the ADC clock comes out the back and then returns to the unit via a SMA jumper. At least in theory you *could* supply your own clock to the unit. How well that wo

Re: [time-nuts] Noise Floor

On 3/24/20 9:26 AM, Anders Wallin wrote: Our experience with the Ettus radios is that although they have 2 channels there is a lot of cross-talk between rx1 and rx2 channels, which makes a diy SDR-based phase-meter challenging. The early USRPs in particular (I don't have as much experience wi

Re: [time-nuts] Noise Floor

On Tue, 24 Mar 2020 18:26:28 +0200 Anders Wallin wrote: > The user-manual provides some details on the internals: > http://www.miles.io/PhaseStation_53100A_user_manual.pdf > Figure 6, page 35, would indicate that there is no analog mixing stage, > just direct ADC. I was in the lucky position tha

Re: [time-nuts] Noise Floor

Hi > On Mar 24, 2020, at 10:01 AM, Attila Kinali wrote: > > Hoi Bob, > > I see you got your hands on a PhaseStation. Color me jealous! :-) If you recall all my grumbles, back in a bit I mentioned my pile of ever more broken test gear. Keeping it all in repair had become so time consuming th

[time-nuts] Mains frequency data for Europe

Hi, Does someone here have recordings of the mains frequency of the west European Grid from the last weeks and from the same time last year? There is something I've been told which I would like to fact-check. I wasn't able to find anything online. Thanks in advance Attila

Re: [time-nuts] Noise Floor

Thanks for posting these! The user-manual provides some details on the internals: http://www.miles.io/PhaseStation_53100A_user_manual.pdf Figure 6, page 35, would indicate that there is no analog mixing stage, just direct ADC. Maybe it also shows the ADCs clocked at (max) 125 MHz, with some HPF and

Re: [time-nuts] Noise Floor

Hoi Bob, I see you got your hands on a PhaseStation. Color me jealous! :-) The noise floor data is impressive! For reference: Expensive DMTD systems for metrological applications are usually at 1e-13 @ 1s and a lot more expensive. I see I have to pester John more on how he designed the PhaseStat

[time-nuts] Noise Floor

Hi Sorry about dumping the text from the previous post !!! Obviously the mailer on that machine needs a bit of attention. So here’s what it *should* have said: When we are doing typical measurements on our time / frequency standards, much of it involves measuring noise. In many ways it is clos