Pages on this website
A PPS driver for Linux systems with GPIO pins (e.g. Raspberry Pi), requiring no kernel patches.
- Lindy Precision Clock driver
I'm developing a driver for the NTP daemon reference implementation for the Lindy Precision Clock.
All that time keeping lingo explained.
Jans is an unusual NTP server: it can return the systemclock time (and just that) but it can also return blatantly incorrect time.
Patch against ntp 4.2.5p158 to enable NMEA-PPS.
- my setup
My servers are part of the NTP pool project. One can see here what my network consists of.
- ntp - be on time, always
For the "deb-a-day"-website I wrote an article trying to convince people to become part of the NTP pool.
- NTP monitor
One can let his/hers NTP server be monitored via this page.
OmniSync is a driver for NTPd for people who are firewall-challenged. It allows you to sync against the daytime service (port 13 tcp/udp), time (port 37 tcp/udp), http and https (both also via proxy server).
- Query NTP server
At this page one can check if their NTP server is reachable over the internet.
Patch to make ppsldisc (Linux PPS patch) behave like a more UNIX-like daemon (forks itself into the background and writes pid to a file).
Links on the net
- Cesium: also known as atomic clock
- DCF77: German time signal
- GPS: Global Positioning System, also emits a time signal
- HBG: Swiss time signal (uses DCF-77 protocol)
- MSF: time signal from NPL (UK)
- NTP: Network Time Protocol, a method for distributing the current time across a network
- OCXO: a crystal in controlled-temperature environment
- PPS: Pulse Per Second
- Rubidium: also known as atomic clock
- TCXO: a crystal oscillator
- TDF: French time signal
- VCO: voltage controlled oscillator
- WWVB: NIST time signal (US)
- Linux PPS
Rodolfo Giometti is developing a PPS implementation for the Linux kernel.
This company has atomic clock watches/clocks/etc. Only for US!
- how atomic clocks work
Web-page describing how atomic clocks work.
- radio clocks for pcs
Building your own radio-clock. Describes hardware for a DCF-77 as well as an MSF receiver.
Describes the 'time'-protocol which can be retrieved via port 37 (TCP and UDP).
Describes the 'network time protocol' (port 123 UDP). This one is preferred over 'time' (port 37) as it also handles delays and jitters correctly.
- Time @ wikipedia
Document in Wikipedia which describes time.
- PIC NTP server
A microcontroller based NTP server, synchronized to a GPS receiver.
- IEEE 1588
A precision clock synchronization protocol for networked measurement and control systems.