Our traditional Master Clock, the CSD-5300 Master Clock System Driver, provides access to stable, reliable, and UTC-traceable real time. A Master for Your Master To address the Master Clock aspect, Leitch offers the world-renowned CSD-5300 Master Clock System Driver, which is used by many of the world's major timekeeping organizations. The LEITCH CSD-3901 Master Clock System Driver allows programming of time code user bits. This facility can be used to include a specific time offset in the time code. The operating mode of one or more ADCs in a system can then be set to read this offset. A typical application is the display of GMT in addition to local time.
Reference Clock Drivers
Leitch Csd-5300 Manual
From top:
- Austron 2100A GPS Receiver with LORAN-C assist
- Austron 2000 LORAN-C Receiver>
- Spectracom 8170 WWVB Receiver
- Hewlett Packard 5061A Cesium Beam Standard
Leitch Csd-5300 Manual
The TardisSupport for most of the commonly available radio and modem referenceclocks is included in the default configuration of the NTP daemon forUnix ntpd
. Individual clocks can be activated by configurationfile commands, specifically the server and fudgecommands described in the ntpd
program manualpage. The following discussion presents Information on how to selectand configure the device drivers in a running Unix system.Radio and modem clocks by convention have addresses in the form127.127.t.u, where t is the clock type and u is aunit number in the range 0-3 used to distinguish multiple instances ofclocks of the same type. Most of these clocks require support in theform of a serial port or special bus peripheral, but some can workdirectly from the audio codec found in some workstations. The particulardevice is normally specified by adding a soft link/dev/deviceu to the particular hardware device involved,where u correspond to the unit number above.
Most clock drivers communicate with the reference clock using aserial port, usually at 9600 bps. There are several application programinterfaces (API) used in the various Unix and NT systems, most of whichcan be detected at configuration time. Thus, it is important that theNTP daemon and utilities be compiled on the target system or clone. Insome cases special features are available, such as timestamping in thekernel or pulse-per-second (PPS) interface. In most cases these featurescan be detected at configuration time as well; however, the kernel mayhave to be recompiled in order for them to work.
The audio drivers are a special case. These include support for theNIST time/frequency stations WWV and WWVH, the Canadian time/frequencystation CHU and generic IRIG signals. Currently, support for the Solarisand SunOS audio API is included in the distribution. It is left to thevolunteer corps to extend this support to other systems. Furtherinformation on hookup, debugging and monitoring is given in the Audio Drivers page.
Some drivers depending on longwave and shortwave radio services needto know the radio propagation time from the transmitter to the receiver,which can amount to some tens of milliseconds. This must be calculatedfor each specific receiver location and requires the geographiccoordinates of both the transmitter and receiver. The transmittercoordinates for various radio services are given in the Stations, Frequencies and Geographic Coordinates page.Receiver coordinates can be obtained or estimated from various sources.The actual calculations are beyond the scope of this document.
Following is a list showing the type and title of each drivercurrently implemented. The compile-time identifier for each is shown inparentheses. Click on a selected type for specific description andconfiguration documentation, including the clock address, reference ID,driver ID, device name and serial line speed, and features (linedisciplines, etc.). For those drivers without specific documentation,please contact the author listed in the CopyrightNotice page.
Type 1 Undisciplined Local Clock(LOCAL)
Type 2 Trak 8820 GPS Receiver(GPS_TRAK)
Type 3 PSTI/Traconex 1020 WWV/WWVHReceiver(WWV_PST)
Type 4 Spectracom WWVB and GPS Receivers(WWVB_SPEC)
Type 5 TrueTime GPS/GOES/OMEGA Receivers(TRUETIME)
Type 6 IRIG Audio Decoder(IRIG_AUDIO)
Type 7 Radio CHU Audio Demodulator/Decoder(CHU)
Type 8 Generic Reference Driver(PARSE)
Type 9 Magnavox MX4200 GPS Receiver(GPS_MX4200)
Type 10 Austron 2200A/2201A GPS Receivers(GPS_AS2201)
Type 11 Arbiter 1088A/B GPS Receiver(GPS_ARBITER)
Type 12 KSI/Odetics TPRO/S IRIG Interface(IRIG_TPRO)
Type 13 Leitch CSD 5300 Master Clock Controller(ATOM_LEITCH)
Type 14 EES M201 MSF Receiver (MSF_EES)
Type 15 * TrueTime generic receivers
Type 16 Bancomm GPS/IRIG Receiver (GPS_BANCOMM)
Type 17 Datum Precision Time System (GPS_DATUM)
Type 18 NIST Modem Time Service(ACTS_NIST)
Type 19 Heath WWV/WWVH Receiver(WWV_HEATH)
Type 20 Generic NMEA GPS Receiver(NMEA)
Type 21 TrueTime GPS-VME Interface (GPS_VME)
Type 22 PPS Clock Discipline(PPS)
Type 23 PTB Modem Time Service(ACTS_PTB)
Type 24 USNO Modem Time Service(ACTS_USNO)
Type 25 * TrueTime generic receivers
Type 26 Hewlett Packard 58503A GPSReceiver (GPS_HP)
Type 27 Arcron MSF Receiver(MSF_ARCRON)
Type 28 Shared Memory Driver(SHM)
Type 29 Trimble Navigation Palisade GPS(GPS_PALISADE)
Type 30 Motorola UT Oncore GPS(GPS_ONCORE)
Type 31 Rockwell Jupiter GPS (GPS_JUPITER)
Type 34 Ultralink WWVB Receivers
Type 35 Conrad Parallel Port Radio Clock(PCF)
Type 36 Radio WWV/H AudioDemodulator/Decoder(WWV)
Type 37 Forum Graphic GPS Dating station(FG)
* All TrueTime receivers are now supported by one driver, type 5.Types 15 and 25 will be retained only for a limited time and may bereassigned in future.
Additional Information
Leitch Csd-5300 User Manual
Mitigation Rules and the preferKeyword
Debugging Hints for Reference Clock Drivers
Line Disciplines and Streams Drivers
Reference Clock Audio Drivers
Pulse-per-second (PPS) Signal Interfacing
How To Write a Reference Clock Driver
The Network Time Protocol (NTP)Distribution