Calibration

Calibration of the PXIe-6674T consists of verifying the measurement accuracy of the device and correcting for any measurement error. The PXIe-6674T is factory calibrated before shipment at approximately 25 °C to the levels indicated in the PXIe-6674T Specifications. The associated calibration constants—the corrections that were needed to meet specifications—are stored in the onboard nonvolatile memory (EEPROM). The driver software uses these stored values.

Factory Calibration

The factory calibration of the PXIe-6674T involves calculating and storing four calibration constants. These values control the accuracy of two features of the device, which are discussed in the following sections.

OCXO Frequency

The OCXO frequency can be varied over a small range. The output frequency of the OCXO is adjusted using this constant to meet the specification listed in the PXIe-6674T Specifications.

PXI_CLK10 Phase

When using the PLL to lock PXI_CLK10 to an external reference clock, the phase between the clocks can be adjusted. The time between rising edges of PXI_CLK10 and the input clock is minimized using this constant.

Note The PXI_CLK10 phase is set during manufacturing and does not need to be recalibrated.