9. Use Channel A for CDR

DUT's will have one or more PLLs and for each PLL the DCA-M oscilloscope must recover the clock from one of the PLL's lanes. However, on DCA-Ms, input Channel A is dedicated to clock recovery and measurements. All other DCA-M input channels are for measurements only and cannot be used to recovery the clock.

Invalid Setup

The following setup will not work, because all lanes of switch 2 in the N7731C are routed to the N1092B's Channel B for which clock recovery is not available. If you try to create this Hardware Diagram, FlexOTO will display the following message:

"Connect DUT Fixture 2 Lane 1 to a DCA-M Measurement channel with clock recovery or add a lane to the clock domain that can be used for clock recovery at the same time."

This Setup Works!

The solution to this problem is to swap one or more DUT lanes so that each DUT will have at least one lane connected to Channel A on the N1092B. This is shown in the following drawing.