TDR/TDT Module Characterizes Multiport 25/28/100-Gb/s Designs

January 27, 2014. Agilent Technologies Inc. today introduced the Agilent N1055A 35/50-GHz (8-ps) time-domain reflectometry and transmission module for the Agilent 86100D DCA-X platform. The module provides fast, accurate impedance and S-parameter measurements on high-speed designs that have up to 16 ports.

On next-generation digital communication systems such as IEEE 802.3ba/bj/bm (40-Gb/100-Gb Ethernet), engineers face significant challenges, such as assessing crosstalk across many channels and controlling impedance at faster edge speeds.

The 86100D DCA-X oscilloscope mainframe can be configured with one to four N1055A TDR/TDT plug-in modules to provide a 2- to 16-channel TDR/TDT measurement system that is both economical and accurate. The 2/4 port TDR/TDT remote heads can be configured with a sampler bandwidth of 35 GHz or 50 GHz, providing single-ended and differential measurement capability, including True-Mode stimulus functionality.

“Time domain reflectometry is an intuitive and easy-to-use method for characterizing signal paths,” said Jay Alexander, vice president and general manager of Agilent’s Oscilloscope and Protocol Division. “But as the industry transitions to higher data rates, classic TDR measurement instruments may no longer have the performance required for new designs. Agilent’s new 86100D-based TDR/TDT solution is engineered to give customers the fast and accurate impedance and S-parameter measurements they need for their next-generation designs.”

High-Resolution TDR/TDT Measurements

High TDR resolution is essential for accurately characterizing complex high-speed structures such as connectors, interconnects, and printed-circuit boards that must operate at data rates to 28 Gb/s and beyond. With TDR step edge speeds as fast as 8 ps and receiver bandwidths of 50 GHz, the DCA-TDR solution resolves the magnitude and location of impedance discontinuities.

Fast, Accurate Multiport S-Parameters

With Agilent 86100D Option 202 enhanced impedance and S-parameter analysis software, scattering parameters (S-parameters) are generated in real time within the oscilloscope and simultaneously displayed with time-domain results. The N1055A’s fast rise time enables calibrated S-parameter measurements to 50 GHz and above. The high-channel-count capability of the DCA-TDR solution also helps to minimize cable reconnections and facilitate more efficient near-end crosstalk and far-end crosstalk measurements in both R&D and high-volume test applications.

TDR/TDT calibration dramatically enhances measurement accuracy by removing systematic imperfections in the instrumentation as well as the impact of adapters, cables, and fixtures used to connect to the DUT. The DCA-TDR solution achieves a breakthrough for accuracy and ease-of-use with its support for electronic calibration (ECal) modules, leveraging a calibration technique originally developed for vector network analyzers. A special Agilent N4694A DC 67-GHz ECal module was developed for the DCA-TDR to let users calibrate and de-skew channels and TDR modules quickly. The result is a fully integrated TDR/TDT/S-parameter measurement system that provides calibrated results on up to 16 channels in real-time.

For more on the N1055A 35/50-GHz (8-ps) time-domain reflectometry and transmission module visit

Agilent will be highlighting the N1055A among other solutions at DesignCon. Visit here for more.


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