词条 | BPM (time service) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
释义 |
BPM is the call sign of the official short-wave time signal service of the People's Republic of China, operated by the Chinese Academy of Sciences, broadcasting from CAS's National Time Service Center in Pucheng County, Shaanxi at {{Coord| 34|56|55.96|N|109|32|34.93|E|type:landmark_region:CN-61|display=it}}, roughly 70 km northeast of Lintong,[1] 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 same frequencies as WWV and WWVH, following the schedule listed below:[2]
Transmission format{{Listen|filename=Bpm_cut.ogg|title=Sample of BPM time signal|description=The BPM time signal, recorded at 2007-01-07 in Beijing}}{{Listen|filename=BPM_5_MHz_record,_start_at_21-07-58_18_Jul_2018.ogg|title=BPM time signal with 125 Hz sub-carrier|description=The BPM time signal, recorded at 2018-07-18 on WebSDR from Netherlands}}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 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.[6]
References1. ^{{cite web | url = http://english.ntsc.cas.cn/rs/fs/200909/t20090917_39104.html | title = National Time Service Center: Facilities}} 2. ^1 {{cite web |title=短波授时台 |url=http://www.time.ac.cn/center/222.html |website=National Time Service Center |deadurl=yes |archiveurl=https://web.archive.org/web/20150410130817/http://www.time.ac.cn/center/222.html |archivedate=2015-04-10 }} 3. ^{{cite web | url = http://forums.watchuseek.com/f17/question-about-wave-ceptor-frequency-reception-46487.html#post258489 | title = Re: A question about Wave Ceptor frequency reception | author = Marco1971 | date = 2007-01-23 | accessdate = 2011-04-29}} 4. ^1 BIPM Annual Report on Time Activities – Time Signals, retrieved 2011 September 12. 5. ^1 2 [https://bbs.pku.edu.cn/attach/fc/ac/fcac420edd48d7bd/BPM%E7%9F%AD%E6%B3%A2%E6%97%B6%E7%A0%81%E6%8E%88%E6%97%B6%E5%8F%91%E6%92%AD%E6%8A%80%E6%9C%AF%E6%96%B9%E6%A1%88_%E8%92%99%E6%99%BA%E8%B0%8B.pdf Dissemination scheme of BPM shortwave time code time-service] (in chinese), retrieved 2018 August 20. 6. ^{{cite web |url = http://tufi.alphalink.com.au/time/time_hf.html |title = HF (SW) Radio - Time NZ & A |access-date = 2011-04-25 |archive-url = https://web.archive.org/web/20150316215505/http://tufi.alphalink.com.au/time/time_hf.html |archive-date = 2015-03-16 |dead-url = yes |df = }} External links
1 : Shaanxi |
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