Figure 7. Sources and Destinations for PXIe-6674T Signal Routing Operations
Using Front Panel PFIs as Single Ended Inputs
The front-panel PFIs can receive external signals from 0 to +5 V. They can be terminated
programmatically with 50 Ω resistances to match the cable impedance and minimize
reflections.
Note
Terminating the signals with a 50 Ω resistance is recommended when the
source is another PXIe-6674T or any other source with a 50 Ω output.
The voltage thresholds for the front-panel PFI inputs are programmable. The input signal is
generated by comparing the input voltage on the PFI connectors to the voltage output of
software-programmable DACs. The thresholds for the PFI lines are individually
programmable, which is useful if you are importing signals from multiple sources with
different voltage swings.
Using Front Panel PFIs as Single Ended Outputs
The front panel PFI outputs are +3.3 V drivers with 50 Ω output impedance. The outputs can
drive 50 Ω loads, such as a 50 Ω coaxial cable with a 50 Ω receiver. This cable configuration
is the recommended setup to minimize reflections. With this configuration, the receiver sees a
PXIe-6674T User Manual
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© National Instruments
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