Clock Metrics


I meant TDEV not NDEV.

On 4/7/2021 12:16 PM, Hesham via wrote:

Hi All

Attached you find the recent WSTS presentation on Clock Metrics. It describes MDEV and MTIE.


On 4/1/2021 4:09 PM, Elad Wind wrote:

Hi everyone,


Very exciting events around TAP this month



#1   GTC’21 - April 15

Ahmad, Dotan and myself with talk to the benefits of precise timing in DCs,

The lessons learned in enabling timing services, and insights to future of DC Timing

Free registration: (session #31889)


#2   Clock Statistics and Characterization Techniques - By Dr. Marc Weiss, NIST

  • Part 1: April 7 (@ 11am PDT) - OCP TAP bi-weekly meeting
  • Part 2: April 21 (@ 11am PDT) - OCP TAP bi-weekly meeting   




By the end of the 1990's methods of modeling and characterizing clocks had been standardized by people at NIST, HP, and other organizations into IEEE and ITU standards. Dr. Marc Weiss, formerly of the NIST Time and Frequency Division, will give a tutorial summarizing these models and methods. Clocks are usually modeled with deterministic and stochastic parameters. The deterministic parameters are an initial time and frequency offset from the reference standard, and a linear frequency drift term. The stochastic parameters are characterized by five power-law spectra, i.e. the Fourier frequencies in the spectra of the clock noise obey behavior characterized by their power exponent. These Fourier spectra can be determined quickly using three statistical tools based on the Allan Variance. Marc will present the story of clock modeling and characterization in a two-part tutorial. He will first discuss different aspects of the clock model illustrating them in data from H-masers at NIST. He then will show characterization techniques using the Allan Variance, the Modified Allan Variance, and the Time Variance.


About Marc Weiss

Mathematician Marc Weiss in the NIST Boulder laboratory that controls an experimental demonstration of time transfer over commercial telecommunications networks. In the experiment, equipment in this room locks onto NIST’s official version of international time, transfers time signals back and forth between NIST and U.S. Naval Observatory time services in Colorado Springs, and measures system time transfer accuracy.






Elad Wind, TAP Project Lead