Optical CDR Caution
To Safely Perform Optical Clock Recovery Using DCA-M Modules
When performing optical clock recovery, always select the Enable High Gain setting on N1077B and N1078A DCA-M modules that support this feature.
Avoid damaging DCA-M modules when performing clock recovery on optical signals by performing the following steps in the order given.
To setup optical clock recovery
- In the module's Setup dialog, select the Clock Recovery tab. In the tab Input field, select the clock recovery input source to be optical.
- Connect the jumper cable between the electrical Data Out and Data In + connectors as shown in the following figure.
- In the Input field of the Setup dialog's Clock Recovery tab, the Select Enable High Gain.
Always enable high gain after performing steps 1 and 2.
If the Clock Recovery tab does not include the Enable High Gain setting, you can safely omit this step as this feature is not supported on the DCA-M module that you are using.
To turn off optical clock recovery
- Clear the Enable High Gain, setting or press Setup > Default Setup.
- Remove the jumper cable.
General Cautions
Never exceed maximum optical input signal power to the Data In connector regardless of the state of the Enable High Gain setting. Failure to observe this caution will result in damage to the instrument.
Before selecting Enable High Gain, always connect the supplied semi-ridged jumper cable between the electrical Data Out and Data In + connectors. Failure to observe this caution may result in damage to the instrument.
Always clear Enable High Gain before disconnecting the supplied semi-ridged jumper cable between the electrical Data Out and Data In + connectors. Failure to observe this caution may result in damage to the instrument.
When Enable High Gain is selected, never connect an electrical cable to the electrical Data In + connectors except for the supplied semi-ridged jumper cable which connects the intstrument's Data Out and Data In + connectors. Failure to observe this caution may result in damage to the N1078A.
Enable High Gain is only displayed in the dialog when a DCA-M is connected and is only active when an optical channel is selected.