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The Time from NPL is a radio signal broadcast from the Anthorn Radio Station near Anthorn, Cumbria, which serves as the United Kingdom's national time reference.〔(【引用サイトリンク】publisher=National Physical Laboratory, UK )〕 The time signal is derived from three atomic clocks installed at the transmitter site, and is based on time standards maintained by the UK's National Physical Laboratory (NPL) in Teddington.〔(【引用サイトリンク】publisher=National Physical Laboratory, UK )〕 The service is provided by Babcock International (with which former providers VT Communications merged) under licence from the NPL and is funded by the Department for Business, Innovation and Skills.〔 The signal, also known as the MSF signal (and formerly the Rugby clock) is broadcast at a highly accurate frequency of 60 kHz and can be received throughout the UK, and in much of northern and western Europe. The signal’s carrier frequency is maintained at 60 kHz to within 2 parts in 1012, controlled by caesium atomic clocks at the radio station.〔 == History == A radio station at Rugby was first operated by the Post Office from 1926, with the call-sign GBR. From 19 December 1927, it broadcast a 15.8 kHz time signal from the Royal Observatory which could be received worldwide. It consisted of 306 pulses in the five minutes up to and including 10:00 and 18:00 GMT, with a longer pulse at the start of each minute. Frequency-shift keying was added in 1967, making the signal harder to use as a frequency reference. The time signals, preceded by the callsign "GBR GBR TIME" in morse code, were transmitted during the 5 minutes preceding 03:00, 09:00, 15:00 and 21:00. Transmitter GBZ on 19.6 kHz was used as a reserve, when GBR was off-air for maintenance. Eventually, time signals from GBR were terminated in November 1986 and it is no longer used as a frequency reference.〔 The MSF signals started in 1950, following the transmission pattern described below. They were originally intended to provide frequency references at 2.5, 5 and 10 MHz, originally only occasionally during the day. At first, there were announcements every fifteen minutes, beginning with the Morse code representation of "MSF MSF MSF" (MSF is "-- ··· ··-·" in Morse code), followed by speech "This is MSF, Rugby, England, transmitting ...".〔(【引用サイトリンク】url=http://www.npl.co.uk/science-technology/time-frequency/time/faqs/what-does-msf-stand-for-(faq-time) )〕 From May 1953, the signal was broadcast 24 hours a day, but with regular five-minute stoppages to allow the reception of other signals. The 60 kHz signal finally became an uninterrupted 24-hour service in 1966, and the frequency references were discontinued in February 1988.〔 On 27 February 2007 the NPL started tests of the new time signal transmissions from Anthorn. This station is operated by VT Communications.〔(【引用サイトリンク】title=MSF Radio Time Signal )〕 The formal inauguration of the relocated facility took place on 1 April 2007, when the name of the service became "The Time from NPL" and the signal from Rugby was permanently switched off. The change in location and consequent change in signal strength can make some equipment designed to use the MSF signal fail to continue doing so. This is found more in domestic equipment not designed for optimum sensitivity and positioned haphazardly. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Time from NPL」の詳細全文を読む スポンサード リンク
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