BPM is the call sign of the official short-wave

time signal A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day. Church bells or voices announcing hours of prayer gave way to automatically operated chimes on public clocks; however, a ...

service of the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, operated by the

Chinese Academy of Sciences The Chinese Academy of Sciences (CAS); ), known by Academia Sinica in English until the 1980s, is the national academy of the People's Republic of China for natural sciences. It has historical origins in the Academia Sinica during the Republi ...

, broadcasting from CAS's

National Time Service Center The National Time Service Center (NTSC; ) has the task of generating, maintaining and broadcasting standard time in China. It is located in Xi'an, Shaanxi, China. Its predecessor was the Shaanxi Astronomy Observatory of the Chinese Academy of Scien ...

Pucheng County, Shaanxi Pucheng County () is a county in the east of Shaanxi province, China. It is under the administration of the prefecture-level city of Weinan Weinan () is a prefecture-level city in the east central Shaanxi province, China. The city lies on the lo ...

at , roughly 70 km northeast of

Lintong Lintong District (), formerly Lintong County, is one of 11 urban districts of the prefecture-level city of Xi'an, the capital of Shaanxi Province, Northwest China. The district was approved to establish from the former ''Lintong County'' () by th ...

, along with NTSC's long-wave time signal BPL on 100 kHz. BPM is broadcast at 2.5, 5.0, 10.0, and 15.0

MHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...

, the same frequencies as WWV and

WWVH WWVH is the callsign of the U.S. National Institute of Standards and Technology's shortwave radio time signal station located at the Barking Sands Missile Range, in Kekaha, on the island of Kauai in the state of Hawaii. WWVH is the Pacific si ...

, following the schedule listed below:

Transmission format

BPM transmits different signals on a half-hour schedule, modulated with 1 kHz audio tones to provide second and minute ticks: BPM is idiosyncratic in that it transmits

UT1 Universal Time (UT or UT1) is a time standard based on Earth's rotation. While originally it was mean solar time at 0° longitude, precise measurements of the Sun are difficult. Therefore, UT1 is computed from a measure of the Earth's angle with ...

time between minutes 25 through to 29 and 55 through to 59, which creates an odd click-beep effect when heard below a stronger time signal station such as WWV especially when UT1 seconds are halfway between UTC seconds, close to a leap-second event.

References

External links

National Time Service Center

from the National Time Service Center, Chinese Academy of Sciences https://www.sigidwiki.com/wiki/BPM Time signal radio stations Radio stations in China Shortwave radio stations {{PRChina-stub