Digital transmission system testing puts greater demands on test equipment. Jitter and timing errors can cause intermittent problems that are difficult to troubleshoot. Researchers at the National Institute of Standards and Technology (NIST) recognized the need for improved accuracy and clarity when analyzing signals using high-speed oscilloscopes and developed a method for correcting common timing errors in these instruments.
The NIST Tech Beat article NIST Method Improves Timing in Oscilloscopes explains, "The NIST method, based on an approach developed in laboratory experiments and implemented in freely available software, constructs an alternative time base. The software analyzes an oscilloscope's measurements of both a signal of interest and two reference waves that are offset from each other. The reference waves are generated by an external device and are synchronized in time with the signal being measured. Measurements of the reference waves are compared with a calculation of an ideal wave to produce an estimate of total time errors due to distortion and jitter. These errors then can be corrected automatically for each measurement made by the oscilloscope."
NIST said the correction method can be applier to older standard equipment, can correct time records of almost any length, and can be applied to electromagnetic signals of almost any frequency. The Time Correction software package is available free of charge at www.boulder.nist.gov/div815/HSM_Project/Software.htm.
