The Casio Wave Ceptor is a line of radio watch

Radio clock

A radio clock or radio-controlled clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock...

es by Casio

Casio

is a multinational electronic devices manufacturing company founded in 1946, with its headquarters in Shibuya, Tokyo, Japan. Casio is best known for its electronic products, such as calculators, audio equipment, PDAs, cameras, musical instruments, and watches...

. Wave Ceptor watches are able to calibrate themselves to the correct time by receiving time signal

Time signal

A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...

s from various government time services around the world. These signals are normally driven directly by ultra-accurate atomic clock

Atomic clock

An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...

s, and so by synchronizing with the signals, the Wave Ceptor watches achieve long-term accuracy - the same accuracy as the atomic clocks that drive the time signals, which is on the order of one second in three million years.

The Wave Ceptor watches are not the only radio-controlled wristwatches on the market. The German manufacturer Junghans

Junghans

Junghans Uhren GmbH is Germany's largest watch and clock manufacturer.The company is located in Schramberg, Baden-Württemberg. On 15 April 1861 Erhard Junghans created the company „Junghans und Tobler“ together with his brother-in-law Jakob Zeller-Tobler in Schramberg .The company began to produce...

 and Japanese manufacturer Citizen Watch Co.

Citizen Watch Co.

is the core company of a Japanese global corporate group based in Tokyo, Japan. The company was originally founded as Shokosha Watch Research Institute in 1918 and is currently known as the manufacturer of CINCOM precision lathe machine tools as well as CITIZEN watches. The trade name originated...

 also have this feature. Like most radio-controlled watches, the Wave Ceptor watches require no setting or resetting of time, date, daylight saving time

Daylight saving time

Daylight saving time —also summer time in several countries including in British English and European official terminology —is the practice of temporarily advancing clocks during the summertime so that afternoons have more daylight and mornings have less...

, or year; and like most other watches of this kind, they synchronize at least every 24 hours, usually in the middle of the night. Their long-term and short-term accuracy is thus better than 500 ms

Millisecond

A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....

.

As with all radio-controlled watches they revert to free-running quartz

Quartz clock

A quartz clock is a clock that uses an electronic oscillator that is regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks are at least an order of magnitude more accurate than good mechanical clocks...

 accuracy in areas out of range or shielded from time setting signals. The time setting signals usually come from radio emitting towers. However, they are still as accurate as other quartz watches in this mode.

The receivers to which the watches can tune themselves vary by watch submodel. CASIO mentions that in Europe, the watches will tune to the low frequency

Low frequency

Low frequency or low freq or LF refers to radio frequencies in the range of 30 kHz–300 kHz. In Europe, and parts of Northern Africa and of Asia, part of the LF spectrum is used for AM broadcasting as the longwave band. In the western hemisphere, its main use is for aircraft beacon,...

 time signal

Time signal

A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...

 radio station DCF77

DCF77

DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. It is operated by Media Broadcast GmbH , on behalf of the Physikalisch-Technische Bundesanstalt, Germany's...

 located at Mainflingen

Mainflingen

Mainflingen is a small settlement of about 3800 inhabitants, a constituent community of the municipality Mainhausen in Hesse, Germany....

 in Germany or MSF at Anthorn

Anthorn

Anthorn is a village in Cumbria, England. It is situated on the south side of the Solway Firth, on the Wampool estuary, about thirteen miles west of Carlisle...

 (formerly transmitting from Rugby, Warwickshire

Rugby, Warwickshire

Rugby is a market town in Warwickshire, England, located on the River Avon. The town has a population of 61,988 making it the second largest town in the county...

) in the United Kingdom. In Europe the reception range is approximately 1500 kilometres. In the United States, they will tune into WWVB

WWVB

WWVB is a NIST time signal radio station near Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks in most of North America use to synchronize themselves. The signal transmitted from WWVB is a continuous 60 kHz carrier wave, derived from a set of atomic...

 at Fort Collins. In Japan, they will tune to JJY

JJY

JJY is the call sign of a low frequency time signal radio station.The station is located in Japan and broadcasts from two sites, one on Mount Otakadoya, near Fukushima, and the other on Mount Hagane, located on Kyushu Island...

 on 40 kHz Mont Otakadoya, and 60 kHz Mont Hagane. In China, they will tune to BPC

BPC (time signal)

BPC is the callsign of a time signal transmitter in China. It was inaugaurated on April 25, 2002 and transmits a time signal on 68.5 kHz, which can be used for steering radio controlled clocks. As opposed to to other time signal transmitters therefore, a special license is required. The TX-site is...

 at Shangqiu

Shangqiu

Shangqiu is a city in eastern Henan province, Central China. It borders Kaifeng to the northwest, Zhoukou to the southwest, and the provinces of Shandong and Anhui to the northeast and southeast respectively. An ancient city with a rich history, Shangqiu was also the first capital of the Shang...

. Some watches can register only some of these signals.

External links

• Official Wave Ceptor Website
• Casio website
• Manuals for Casio watches; requires Adobe Reader
  Adobe Acrobat
  Adobe Acrobat is a family of application software developed by Adobe Systems to view, create, manipulate, print and manage files in Portable Document Format . All members of the family, except Adobe Reader , are commercial software, while the latter is available as freeware and can be downloaded...