National Instruments PXI-6683H PXI Synchronization Modules

The National Instruments PXI-6683H Synchronization Module has a GPS receiver, which controls a dynamic GPS antenna and processes the RF signals (1.575 GHz) from the satellites. The GPS receiver then creates an extremely exact pulse per second (PPS) that the NI PXI-6683H uses to accomplish sub-microsecond synchronization.  

The GPS is an arrangement of more than 2 dozen satellites in medium Earth orbit that are continually transmitting signals down to earth. GPS receivers can distinguish these signals and determine area, speed, direction and time very precisely. GPS satellites are fitted with atomic clocks, and the signals they transmit to Earth contain timing data. This makes the GPS framework a precise timing and synchronization source.

IRIG-B IRIG is another important function on the NI PXI-6683H, which is a standard used to transmit exact timing data between instruments to accomplish synchronization. IRIG-B is a specific use of the IRIG standard, in which 100 bits of information are sent each second. Inserted in the information is a seconds' limit marker that the accepting instrument uses to synchronize its time-base to the IRIG source. Whatever is left of the information contains data, such as the time of day, days since the start of the year, and alternatively, control functions, and the quantity of seconds since the beginning of the day, encoded as a straight binary number.

The NI PXI-6683H module is equipped for utilizing a PPS (pulse per second) signal for synchronization. Any PFI, PXI_Trigger or PXI_Star line can be configured as the PPS input terminal.