Keysight Technologies N4917BSCB 400G User Manual

Contents

Keysight Technologies N4917BSCB 400G User Manual Manual pdf 70 page image

70 Keysight N4917BSCB 400G Optical Receiver Test Application User Guide5 Performing Stressed Receiver Compliance Tests with N4917BSCB SoftwareCalibrating the stressed receiver conformance test signalThe normative requirement for optical receivers to be compliant accordingto the IEEE 802.3bs/cd standards is the stressed receiver sensitivity whichis measured with the methods defined in IEEE 802.3bs section 121.8.9using the conformance test signal described in section 121.8.9.2 and inIEEE 802.3cd sections 138.8.10, 139.7.10, and 140.7.10 for the relevantstandards.The N4917BSCB compliance test solution offers a fully automatedcalibration procedure to generate this compliance test signal which is thenused to perform the stressed receiver sensitivity measurement anddetermine the receiver compliance.Figure 24 Unavailable tests due to missing instrument connectionsOptimizing the BERT deemphasisRunning the automated conformance test signal calibration requires anoptimized BERT output that compensates the non-ideal frequencyresponse on the signal path due to amplifiers and E/O converter.Hence, it is recommended to run an automated BERT deemphasisoptimization prior to the stressed receiver conformance test signalcalibration. By default, running the "Auto-calibration of stressed eyesignal" automatically performs a BERT deemphasis optimization prior tostarting the actual calibration procedure. This feature can be disabled bychanging the value of the "Optimize deemphasis on calibration start"configuration variable to false. Alternatively, the BERT deemphasisoptimization can be performed separately by running the "Optimize BERTdeemphasis" test from the Utility functions.NOTE To run the automated calibration from the test tree (Select tests tab), allinstruments in the Set Up tab needs to be connected and configuredsuccessfully, otherwise one or more tests will be unavailable.