Time and Frequency

The second is one of the base units defined in the International System of Units (SI) and is defined as follows: The duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium-133 atom. The measurement traceability to the SI of our time and frequency measurements is obtained using our rubidium standards that have been calibrated at the National Research Council of Canada.

Our calibration measurement capability, meeting the requirements of our SCC accreditation to ISO/IEC 17025:2017 and the NRC CLAS certification, is within ±3.3E-10 over the range of 1 Hz to 550 MHz. During the past 25 years our measurement system has been monitored with statistical process control charts that demonstrate our measurement system is well within our scope of accreditation.

The devices we calibrate within our time and frequency capability range from mechanically activated stopwatches to electronic frequency counters.

Our complete accredited scope may be seen on the National Research Council’s CLAS web site: scope >