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RBU is a time code radio station located in Moscow (). It transmits a continuous 10 kW time code on 66⅔ kHz.〔 Supplement to Recommendation ITU-R TF.768 “Standard frequencies and time signals”.〕 This is commonly written as 66.66〔 or 66.666 kHz, but is actually 200/3 = 66.6̅ kHz.〔 Until 2008, the transmitter site was near Kupavna and used as antenna three T-antennas spun between three 150 metres tall grounded masts. In 2008, it has been transferred to the Taldom transmitter at . == Time code == Every 100 ms, synchronized to the UTC second, one bit is transmitted: 100 Hz modulation encodes a binary 0, while 312.5 Hz modulation encodes a binary 1. Each UTC second consists of 10 such bits. 6 of them are fixed, two encode minute boundaries, and two provide time code information: Each minute, the two bits of time code encode the local time of the following minute (like DCF77) and some additional information. Because the time code starts with two 1 bits, the top of the minute is uniquely marked by 5 consecutive 1 bits.〔See (Nils Schiffhauer's radio monitoring pages ). Under "Audio Clips - Medium Wave (& Longwave)" are audio samples of several time signal stations, including both an audio clip and a spectrogram "waterfall diagram" of RBU at the top of the hour. It clearly shows the 0.1 second bits producing sidebands straddling the carrier at ±100 Hz and ±312.5 Hz, and the 5 consecutive 1 bits marking the top of the minute. The carrier has been shifted down by 66.0 kHz, so it shows up on the plot at 666⅔ Hz.〕 dUT1 is an additional, higher-precision correction to DUT1. UT1 = UTC + DUT1 + dUT1. Bits with a weight of ± are 0 for positive, 1 for negative. The time transmitted is Moscow local time; UTC can be computed by subtracting the value of the ΔUT field. 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「RBU (radio station)」の詳細全文を読む スポンサード リンク
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