See eight differential pairs at 60 GHz
Martin Rowe - September 28, 2012High-speed serial buses such as IEEE 802.3ba need the highest-bandwidth oscilloscopes to get accurate views of their waveforms. With 100 Gbps links using four 25-Gbps lanes, each a differential pair, you need two channels to characterize each lane. FPGAs may have more than one 100-Gbps link, so you may need more than one set of four oscilloscope channels. Agilent Technologies’ N1045A sampling oscilloscope module accepts two or four inputs at 60 GHz, depending on options. You can combine up to four modules in a 86100D DCA-X mainframe to get 16 inputs. A fully loaded mainframe lets you characterize up to eight lanes at once. The modules are available with two or four channels.
The N1045A has it’s digitizer in the module, minimizing the electrical distance between the measurement point and the digitizer. According to Agilent’s product manager Robert Sleigh, the module’s digitizer is 1 cm from its input connector. A cable brings power from the mainframe to the sampling module. LEDs on each module correspond to oscilloscope color traces.
The modules are also available with standard jitter or low-jitter options through the addition of the 86107A Precision Timebase Module in the DCA-X mainframe. Adding the 86017A to a system lowers the jitter from approximately 800 fs typical to less than 200 fs.
In addition to IEEE 802.3ba, applications for the N1045A sampling module include:
- IEEE 802.3 bj Ethernet for backplanes and cables
- 25 Gbps Infiniband
- 32 Gbps Fiber Channel
- Optical Internetworking Forum OIF/CEI 28G-SR (chip-to-chip)
- OIF/CEI 28G-VSR (chip-to-module)
- OIF/CEI 25G-LR (backplane)