N1077A Optical CDR Test Setups
The illustrations in this topic represent a variety of optical clock recovery using the N1077A. In some situations, the length of the cables used can impact measurement accuracy. For more information, download the N107x-series user's guide at www.keysight.com.
Circled numbers in this figure identify items from the electrical phase matching kits. Optional equalizers can be added to open a closed eye for clock recovery.
Precision Timebase and Trigger Connections from an N107x-Series DCA-M
When using an N107x-series DCA-M clock recovery module with an N1060A, know that the signal from the N107x's Aux Clock Out connector has significantly lower jitter than the signal from the N107x's Recovered Clock Out connector. Therefore:
- Connect the N107x's Aux Clock Out (lower jitter) to the DCA-X's or N1060A's Precision Timebase Input, and
- Connect the N107x's Recovered Clock Out to the DCA-X's Trigger Input.
Example Setup 1. Single-Ended Input, N1077A-SXT, DCA-M Scope
This example setup shows an N1077A-SXT connected to an N1094B oscilloscope with a single-ended electrical input signal. The microwave pickoff is used to tap a portion of the input signal as an input to the clock recovery module.
Example Setup 2. Differential Input, N1077A-SXT, DCA-M Scope
This example setup shows an N1077A-SXT connected to an N1094B oscilloscope with a differential input signal. Two microwave pickoffs are used to tap a portion of the input signal as an input to the clock recovery module.
Example Setup 3. Single-Mode Input, N1077A-SMS, DCA-M Scope
This example setup shows an N1077A-SMS connected to an N1092E oscilloscope. Single-mode fiber can be connected to the N1077A-SMS’s single-mode input connector. Since the N1092-series oscilloscopes do not have a single-mode input, you can use a multimode patchcord in most cases.
Example Setup 4. Multimode Input, N1077A-SMS, DCA-M Scope
This example setup shows an N1077A-SMS connected to an N1092E oscilloscope.
