Enhanced Resolution Time-Domain Reflectometry for High Speed Channels: Characterizing Spatial Discontinuities with Non-ideal Stimulus

In the recent past, there has been steady growth in the data transfer rate of modern digital serial communication systems. Consequently, accurate characterization of high-speed signal transmission lines is necessary for ensuring high signal integrity. Time domain reflectometry (TDR) has been widely used in prior research to characterize high speed interconnect. The accuracy of the characterization depends on the sampling rate and the slew rate of the TDR input excitation signal. At high speeds it is not always possible to deliver "perfect" (impulse/step) TDR stimulus. In this paper, an algorithm is presented to compensate for the inherent distortion in nonideal TDR stimulus to improve the accuracy of interconnect characterization. The algorithm is applied to the problem of micro strip transmission line characterization for identifying discontinuities in signal interconnect. Hardware measurements validate the effectiveness of the proposed technique.