[time-nuts] Re: Looking for a new GNSS-receiver for a disciplined oscillator - Which one to buy?

[Georg Sauthoff]

Hello,

for the record, some additional information:

On Sat, Apr 16, 2022 at 12:10:19PM +0200, Georg Sauthoff wrote:
[..]
> The MCX623106GC-CDAT might be a similar successor (100 GBE with PPS
> In/Out, Enhanced-SyncE & PTP GM support and GNSS, PCIe 4.0 x16), but I
> don't even find a dedicated product page for it - let a lone a shop
> listing.

Not a dedicated product page, but Nvidia has a manual on configuring
ts2phc, ptp4l etc. for these NICs:

https://docs.nvidia.com/networking/display/NVIDIA5TTechnologyUserManualv10/PHC%20Synchronization%20with%20Onboard%20GNSS

The manual also specifies the specific GNSS receiver that is used on
these NICs: UBLOX UBX-m8030

cf. https://docs.nvidia.com/networking/display/NVIDIA5TTechnologyUserManualv10/On+Board+GNSS+Receiver

[..]
> Intel also lists a NIC with GPS onboard option, but it's pretty new,
> i.e. probably still at the sample/pre-order stage.

It's a variant of the Intel E810-XXVDA4T NIC:
https://www.intel.com/content/www/us/en/products/sku/211608/intel-ethernet-network-adapter-e810xxvda4t/specifications.html

To be precise, the variant with onboard GNSS receiver is the
E810XXVDA4TGG1 (cf. the Product Brief,
https://cdrdv2.intel.com/v1/dl/getContent/641626).

Some details regarding time syncronisation features (also from the
product brief):


'Onboard high-precision oscillator maintains high
accuracy during holdover (when the synchronization
source is not available), providing up to four hours with
less than +/- 1.5 microsecond of phase error.

Optional GNSS mezzanine enables integrated
support for frequency, phase, and time-of-day
synchronization with Global Navigation Satellite
Systems, including GPS, Galileo, GLONASS, BeiDou,
and QZSS. Available on E810XXVDA4TGG1 only.
Subminiature version B (SMB) coaxial connector allows
connection to an external active GNSS antenna.

Dual external SubMiniature version A (SMA) coaxial
connectors allow connection to external 1PPS timing
sources, such as GNSS signaling, devices and to
timing recipients, enabling the network adapter to act as
a grandmaster and as a timing source for other
equipment. The output capability provides a way to
audit the phase accuracy of each node.

U.FL connectors, embedded coaxial connectors,
allow 1PPS signal connectivity between the adapter and
motherboard or another adapter. Dedicated send and
receive U.FL ports are embedded on the adapter.'


The product brief doesn't name the used GNSS receiver, perhaps Intel
wants to stay flexible and doesn't want to commit to a certain
vendor/module.


FWIW, both the Nvidia and Intel NICs also support SyncE for frequency
synchronisation.

Best regards,
Georg

-- 
'The medium is the message'
    (Marshall McLuhan. Understanding Media: The Extensions of Man. 1964)