1 General Information about DCF77
1 General Information about DCF77
The radio remote clocks made by Meinberg receive the signal from the long wave transmitter DCF77. This long
wave transmitter installed in Mainflingen near Frankfurt/Germany transmits the reference time of the Federal
Republic of Germany. This time reference is either the Central European Time (Mitteleuropäische Zeit, MEZ)
or the Central European Summer Time (Mitteleuropäische Sommerzeit, MESZ). The transmitter is controlled
by the atomic clock plant at the Federal Physical Technical Institute (PTB) in Braunschweig/Germany and
transmits the current time of day, date of month and day of week in coded second pulses. Once every minute
the complete time information is available.
At the beginning of every second the amplitude of the high precision 77.5 kHz carrier frequency is lowered
by 75% for a period of 0.1 or 0.2 sec. The length of these time marks represent a binary coding scheme using
the short time mark for logical zeroes and the long time mark for logical ones. The infomation on the current
date and time as well as some parity and status bits can be decoded from the time marks of the 15th up to the
58th second every minute. The absence of any time mark at the 59th second of a minute signals that a new
minute will begin with the next time mark.
Our radio remote clocks decode the highly accurate information on date and time within a wide range around
Germany. So some of our clocks are installed in Bibao/Spain as well as in the City of Umeå in northern Sweden
- fully statisfying the requirements of the users. The radio remote clocks automatically switch to summertime
and back. The reception of the time information is free of charge and does not need to be registered.
Gernerally it is important to position the antenna in an optimal way. It should be mounted at least 30 cen-
timeters away from the clock unit and from solid steel. The antenna should be aligned at a right angle to the
direction of the transmitter (Frankfurt).
0
10
20
30
40
50
R
M
1
4
2
1
0
2
10
8
4
2
1
P
2
2
0 0
1
8
4
2
1
2
4
8
10
1
2
4
8
10
2
0
4
0
8
0
P
3
A1
1
Z
Z2
A2
S
1
2
4
8
1
0
2
0
4
0
P
1
Kodierung
nach Bedarf
Minute
Stunde
Kalendertag
Wochentag
Kalender-
monat
Kalenderjahr
M
Minutenmarke (0.1 s)
R
Aussendung über Reserveantenne
A1
Ankündigung Beginn/Ende der Sommerzeit
Z1, Z2
Zonenzeitbits
Z1, Z2 = 0, 1:
Standardzeit (MEZ)
Z1, Z2 = 1, 0:
Sommerzeit (MESZ)
A2
Ankündigung einer Schaltsekunde
S
Startbit der codierten Zeitinformation
P1, P2, P3
gerade Paritätsbits
DCF600HS
Date: 24th July 2018
1
