World Library  
Flag as Inappropriate
Email this Article

RBU (radio station)

Article Id: WHEBN0033158118
Reproduction Date:

Title: RBU (radio station)  
Author: World Heritage Encyclopedia
Language: English
Subject: BPC (time signal), OLB5, Y3S, Time transfer, Nauen Transmitter Station
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

RBU (radio station)

RBU is a time code radio station located in Moscow ().[1] It transmits a continuous 10 kW time code on 66⅔ kHz.[2] This is commonly written as 66.66[1] or 66.666 kHz,[3] but is actually 200/3 = 66.6̅ kHz.[2] Until 2008, the transmitter site was near Kupavna . In 2008, it has been transferred to the Taldom transmitter at .[4][5]

Time code

Every 100 ms, synchronized to the UTC second, one bit is transmitted:
RBU tenth second format[6][7]
Start Duration Signal
+0 ms 10 ms Unmodulated carrier
+10 ms 80 ms Carrier PM modulated with 100 Hz or 312.5 Hz tone, modulation index 0.698
+90 ms 5 ms Unmodulated carrier
+95 ms 5 ms Carrier off

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:

RBU second format[6][7]
Start Significance
0 ms Time code data bit 1
100 ms Time code data bit 2
200 ms Always 0 (100 Hz tone)
300 ms
400 ms
500 ms
600 ms
700 ms Always 0, except 1 before start of minute
800 ms
900 ms Always 1 (312.5 Hz tone)

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.[8]

RBU time code[6][7]
Shaded bits are fixed
Second Data bit 1 Data bit 2 Second Data bit 1 Data bit 2
Weight Meaning Weight Meaning Weight Meaning Weight Meaning
00 1 Always 1 1 Always 1 30 4 Year
(00–99)
8 Truncated MJD
(0000–9999)
01 0 Unused, zero +0.1 DUT1
(+0.1–+0.8 s)
Unary encoding,
bit set if
DUT1 ≥ Weight
31 2 4
02 0 +0.2 32 1 2
03 +0.02 dUT1
(+0.02–+0.10 s)
Bit set if
dUT1 ≥ Weight[9]
+0.3 33 10 Month
(01–12)
1
04 +0.04 +0.4 34 8 0 Unused, zero
05 +0.06 +0.5 35 4 0
06 +0.08 +0.6 36 2 0
07 +0.10 +0.7 37 1 0
08 0 Unused, zero +0.8 38 4 Day of week
1=Monday
7=Sunday
0
09 0 −0.1 DUT1
(−0.1–−0.8 s)
Unary encoding,
bit set if
DUT1 ≤ Weight
39 2 0
10 0 −0.2 40 1 0
11 −0.02 dUT1
(−0.02–−0.10 s)
Bit set if
dUT1 ≤ Weight[9]
−0.3 41 20 Day of month
(1–31)
0
12 −0.04 −0.4 42 10 0
13 −0.06 −0.5 43 8 0
14 −0.08 −0.6 44 4 0
15 −0.10 −0.7 45 2 0
16 0 Unused, zero −0.8 46 1 0
17 0 0 Unused, zero 47 20 Hour
(00–23)
0
18 ± ΔUT
Moscow time
minus UTC
Always +4 since
27 March 2011
8000 Truncated
Julian Day
(0000–9999)

Last 4 digits of
Modified Julian
day
number
48 10 0
19 10 4000 49 8 P1 TJD bits 18–25 Even
parity

over
20 8 2000 50 4 P2 TJD bits 26–33
21 4 1000 51 2 0 Unused, zero
22 2 800 52 1 0
23 1 400 53 40 Minute
(00–59)
P3 ΔUT bits 18–23
24 0 Unused, zero 200 54 20 P4 Year bits 25–32
25 80 Year
(00–99)
100 55 10 P5 Month/DoW bits 33–40
26 40 80 56 8 P6 Day bits 41–46
27 20 40 57 4 P7 Hour bits 47–52
28 10 20 58 2 P8 Minute bits 53–59
29 8 10 59 1 0 Unused, zero

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.

References

  1. ^ a b  
  2. ^ a b International Telecommunication Union (6 October 2010), Characteristics of standard-frequency and time-signal emissions in allocated bands and characteristics of stations emitting with regular schedules with stabilized frequencies, outside of allocated bands, retrieved 2014-10-30  Supplement to Recommendation ITU-R TF.768 “Standard frequencies and time signals”.
  3. ^ William Hepburn (2006-10-29), VLF time signal brioadcasts, retrieved 2011-09-20 
  4. ^ "Москва". Vcfm.ru. Retrieved 2012-10-24. 
  5. ^ "RWM". Dic.academic.ru. Retrieved 2012-10-24. 
  6. ^ a b c Klaus Betke (1 August 2002), Standard Frequency and Time Signal Stations on Longwave and Shortwave (PDF), pp. 16–17, retrieved 2011-09-20 . Note that there is a modulation type error in this reference.
  7. ^ a b c Standard Time and Frequency Signals (DOC), pp. 4,15–17, retrieved 2014-08-03  -- official signal specification, in russian.
  8. ^ 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.
  9. ^ a b  
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.