A fast-pulse oscilloscope calibration system

A system is described for calibrating high-bandwidth oscilloscopes using pu lse signals. The fast-pulse oscilloscope calibration system (FPOCS) is to b e used to determine the step response parameters for digitizing oscilloscop es having bandwidths of similar to 20 GHz. The system can provide measureme nt traceability to standards maintained at the U.S. National Institute of S tandards and Technology (NIST), It comprises fast electrical step generatio n hardware, a personal computer (PC) and software, and a reference waveform , i.e., a data file containing an estimate of the step generator output sig nal. The reference waveform is produced by prior measurement by NIST of the step generator output signal (calibration step signal). When the FPOCS is in use, the calibration step signal is applied to the device under test, wh ich is an oscilloscope sampling channel. The measured step waveform is corr ected for timebase errors, then the reference waveform is deconvolved from it. The results are impulse, step, and frequency response estimates, and th eir associated parameters (e.g., transition duration, transition amplitude, -3 dB bandwidth) and uncertainties. The system and its components are desc ribed, and preliminary test results are presented.