Changes in the WWVB Radio Signal Affects Precision Frequency and Timing Reference

Technical & Application Notes

Spectracom had used the WWVB signal to synchronize its time and frequency references and master clocks in North America before the wide-spread use of GPS for precision timing applications. The last of these WWVB products has not been promoted for over 10 years and officially went end-of-life in 2005. A change in the WWVB signal was being considered in recent years to reduce impact of electro-magnetic interference and allowing for improved reception in consumer-grade clocks and watches1. However, this change affects the operation of precise time and frequency standards whose receivers are based on phase-locked loops, such as Spectracom WWVB receivers, so these products will no longer operate as intended.
[1] J.P. Lowe, “We Help Move Time through the Air”, Radio World, March 23, 2011, Vol. 35, No. 8 pp. 69, 70.