Use Time-Based and Signal-Based Synchronization to coordinate hardware device timing in a system.

In Time-Based Synchronization, each piece of time-based hardware shares a common wall-clock time reference. For test and measurement hardware, there are many industry standards for time such as IEEE 1588, GPS, network time protocol (NTP), pulse per second (PPS), and inter-range instrumentation group (IRIG) time codes.

With Signal-Based Synchronization, the system uses physical hardware pulses as a reference for events. Each piece of signal-based hardware in the system shares a hardware clock. The clock can be a shared Sample Clock or a high-frequency Reference Clock. Each signal-based device derives a Sample Clock and a shared start trigger from the shared clock. When multiple signal-based devices are synchronized, they update I/O simultaneously and also drift by the same number of samples over a time period.

The following table displays common use cases for each type of hardware synchronization.

Synchronization Type Use Case
Time-Based
  • Correlate data logged by time-based devices, such as XNET devices.
  • Initiate I/O sampling across time-based devices.
Signal-Based
  • Simultaneously sample I/O across several different data acquisition devices.
  • Update the PWM duty cycle of an FPGA device.
  • Update analog outputs of data acquisition devices.