Dynamic calibration of oscilloscopes and waveform recorders using pulse standards

Abstract

After arguing that virtually no one calibrates oscilloscopes or waveform recorders properly and completely, the author points out that, in most cases, the tools for performing complete and proper calibrations are available when they are required by the application. After a brief introduction describing the current methods used to calibrate oscilloscopes, the problems associated with oscilloscope vertical channel bandwidth testing are discussed and illustrated. Then, a solution that involves pulse signals and an NIST-developed deconvolution algorithm is described. The proposed method for the complete and correct calibration of an oscilloscope voltage channel's speed of response is based on measuring, digitizing, and deconvolving a standard (known) pulse. It is noted that there is an added cost associated with this complete and correct calibration method, and it may not be justified for all applications. For analog oscilloscopes in particular, it may end up being cheaper to purchase a new 'smart' digitizing oscilloscope, well suited to the application of this calibration technique, than to try to apply these methods to the analog scope.<>