Table Of Contents

Performing System Compensation

Last Modified: January 13, 2021

System compensation is a required step in the VCSEL I-V Test Subsystem setup process. You must perform system compensation before you perform pulse compensation and I-V measurements. After the initial setup is complete, you must perform system compensation again if any connections within the VCSEL I-V Test Subsystem change, such as a cable replacement, or if the facility environment exceeds the environmental specifications for the subsystem.

Before you begin, complete the following pre-requisites:
  • Connect the PXI chassis to facility ground and a power source.
  • Install an LO/Sense LO connector assembly on each PXIe-4135 in the PXI chassis.
  • Connect each NI-4134 to the facility ground and a power source.
  • Connect each NI-4134 to a PXIe-4135 and the PXIe-8880.
  • Connect each NI-4134 to a PXIe-4135 and your computer.
NI recommends naming the BNC cables after the NI-4134 pulse generator outputs as follows and marking each BNC cable with an indicator so you can differentiate between cables during compensation and general operation of the VCSEL I-V Test Subsystem.
  • SCOPE cable—BNC cable that connects the load board to a 30 dB attenuator installed on the PXIe-5162 front panel
  • PRIMARY cable—BNC cable that connects the load board to the HIGH SPEED PULSE PRIMARY output on the back panel of the NI-4134 pulse generator
  • SECONDARY cable—BNC cable that connects the load board to the HIGH SPEED PULSE SECONDARY output on the back panel of the NI-4134 pulse generator
spd-note-notice
Notice  

Consistently connect the above BNC cables to the corresponding NI-4134 outputs during the operation of the VCSEL I-V Test Subsystem. Otherwise, the compensation data and measurement results will be inaccurate.

Equipment

The following equipment is required to perform system compensation on one subsystem channel.

  • Male BNC short connector (x1)
  • Female BNC short connector (x1)
  • 30 dB attenuator (x1)
  • BNC (m)-to-BNC (m) cables (x2 for full impedance NI-4134 configuration, x3 for half impedance NI-4134 configuration)
    • PRIMARY cable
    • SECONDARY cable (half impedance NI-4134 configuration only)
    • SCOPE cable

Complete the following steps to perform system compensation.

  1. Select Help»Find Examples from LabVIEW and navigate to Toolkits and Modules»VCSEL I-V Test to open VCSEL System and Pulse Compensation.lvproj.
  2. Open the System Compensation VI.
  3. Follow the instructions on the VI front panel to complete system compensation.
After the system compensation is complete, the System Compensation VI automatically saves the system compensation data for pulse compensation and I-V measurements.

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