New time code to boost reception for radio-controlled clocks

Mar 06, 2013

(Phys.org) —The National Institute of Standards and Technology (NIST) is changing the way it broadcasts time signals that synchronize radio-controlled "atomic" clocks and watches to official U.S. time in ways that will enable new radio-controlled timepieces to be significantly more robust and reliable.

This new broadcast protocol will not only improve the performance of new radio-controlled clocks and watches, but will encourage the development of new timekeeping products that were not practical with the old broadcast system because of local interference or other limitations. For example, appliances such as refrigerators, microwave ovens and thermostats, as well as traffic light timers and sprinkler systems will be able to take advantage of this new phase modulation broadcast.

Popular radio-controlled timekeepers, which range from wristwatches to wall clocks, are not really —though that's often in their name—but they do set themselves by listening to low-frequency AM time broadcasts from the NIST radio station WWVB in Fort Collins, Colo. Those broadcasts are synchronized to the NIST atomic clock ensemble in nearby Boulder, Colo.

However, sometimes the radio-controlled clocks have difficulty accurately picking up the WWVB time signal because of the clock's location, local , effects of buildings, and other problems. Moreover, a time broadcast from England on the same frequency also interferes with devices on the east coast of the United States that rely on the NIST broadcast, according to John Lowe, station manager for WWVB.

video platformvideo managementvideo solutionsvideo player

To solve these problems, Lowe says, NIST has developed, tested and is now beginning to implement the new phase-modulation WWVB signal. Like a traditional AM radio station, time information is encoded in the WWVB broadcast by changes in the strength or amplitude of the radio signal. Phase modulation adds an additional layer of information encoded by shifting the phase of the carrier wave. (The crests of two waves that are "in phase" pass a point at the same time. If one is phase-shifted, the crest will arrive a little before or after the other.)

This change significantly improves signal reception and overall performance of new products that are designed to utilize this new protocol. Legacy clocks and watches will still continue to function as they have because the amplitude modulation remains the same, but they will not benefit from the increased performance of the new phase modulation protocol, Lowe said.

These new products and non-networked systems will be able to take advantage of the improved NIST format thanks to next generation receiver chips that will begin entering the marketplace in 2013.

For more on radio-controlled clocks work with WWVB, see www.nist.gov/pml/div688/grp40/radioclocks.cfm.

Explore further: Lego-like modular components make building 3-D 'labs-on-a-chip' a snap

add to favorites email to friend print save as pdf

Related Stories

New method developed for synchronizing clocks

Jul 20, 2010

Maintaining the correct time is no longer just a matter of keeping your watch wound -- especially when it comes to computers, telecommunications, and other complex systems. The clocks in these devices must stay accurate to ...

Atomic clock signals may be best shared by fiber-optics

Mar 02, 2007

Time and frequency information can be transferred between laboratories or to other users in several ways, often using the Global Positioning System (GPS). But today's best atomic clocks are so accurate—neither gaining nor ...

Random Antenna Arrays Boost Emergency Communications

Feb 25, 2009

(PhysOrg.com) -- First responders could boost their radio communications quickly at a disaster site by setting out just four extra transmitters in a random arrangement to significantly increase the signal power at the receiver, ...

Atomic time for the Raspberry Pi

Jun 26, 2012

A blog post on DesignSpark - an online community for electronic engineers - has described how the Raspberry Pi mini computer can be synchronised with NPL's atomic time scale via the MSF Radio Time Signal.

Recommended for you

Wireless sensor transmits tumor pressure

Sep 20, 2014

The interstitial pressure inside a tumor is often remarkably high compared to normal tissues and is thought to impede the delivery of chemotherapeutic agents as well as decrease the effectiveness of radiation ...

Seeing through the fog (and dust and snow) of war

Sep 19, 2014

Degraded visibility—which encompasses diverse environmental conditions including severe weather, dust kicked up during takeoff and landing and poor visual contrast among different parts of terrain—often ...

User comments : 0