Free Software for Oscilloscope Timebase Corrections
We have demonstrated a new method of correcting both random and systematic timebase errors in sampling oscilloscopes. High-speed sampling oscilloscopes suffer from systematic timebase distortion (TBD) and random jitter that cause errors in the time in a waveform at which samples are acquired. By implementing the NIST correction method, end users can achieve the best aspects of these oscilloscopes by correcting for both random jitter and systematic timebase distortion, thus providing the end user with an estimate of the residual timing error after the correction process has been applied. This method is nonproprietary. Details of the procedure are described in P. D. Hale, C. M. Wang, D. F. Williams, K. A. Remley, and J. Wepman, "Compensation of random and systematic timing errors in sampling oscilloscopes," IEEE Trans. Instrum. Meas., vol. 55, no. 6, pp. 2146- 2154, Dec. 2006. Both the reprint and software package are available on the High-Speed Measurements Project Web site

EEEL Demonstrates Traceable Waveform Measurement up to 200 GHz
In a joint collaboration with the NIST Electromagnetics Division, we have demonstrated temporal waveform measurements, in a coplanar waveguide, that are calibrated and traceable to fundamental physical units using electro-optic sampling techniques. The calibrations, from 500 MHz to 200 GHz, enable us to correct for the complex characteristic impedance and dispersion of the coplanar waveguide, impedance mismatches, and multiple reflections in the measurement system. Because they are calibrated, these measurements make it possible to calculate such quantities as the Thevenin and Norton equivalent circuits describing the electrical source, and can be used to calibrate future generations of temporal on-wafer measurement systems. This work will support future generations of high-speed components and test equipment that are necessary for 40 Gbit/s and faster fiber-optic communications systems that cannot be supported by present-day state-of-the-art oscilloscopes, whose bandwidths are limited by their coaxial connectors.

Although electro-optic sampling has been used to measure high-speed electrical waveforms for many years, the EEEL measurements are the first mismatch-corrected waveform measurements (using any method) that include a full time-domain uncertainty analysis and are calibrated up to 200 GHz, a factor of four improvement over previous achievements elsewhere. The team quantified the uncertainty in the temporal measurement using a Monte-Carlo simulation that included both systematic and random sources of uncertainty from a measurement of a 5.96 ps pulse with a 95% confidence interval of only 0.21 ps. This time-domain uncertainty analysis is the first of its kind. Details of the procedure are described in D.F. Williams, P.D. Hale, T.S. Clement, and J.M. Morgan, "Calibrated 200 GHz Waveform Measurement," IEEE Trans. Microwave Theory and Tech., Vol 53, no. 4, pp. 1384-1389,April 2005.