Meinberg RU226 - Manual

FUNKUHREN
RU226
DCF77-receiver
General information about DCF77
The Meinberg receiver module RU226 receives the signal of the long wave transmitter DCF77.
This long wave transmitter installed in Mainflingen near Frankfurt/Germany transmits the refe-
rence time of the Federal Republic of Germany. This time reference is either the Central European
Time (MEZ) or the Central European Summer Time (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. The complete time information is available once every
minute.
At the beginning of every second the amplitude of the high precision 77.5kHz carrier frequency
is shifted to 25% for a period of 0.1 or 0.2 sec. The length of these time marks represents a binary
coding scheme using the long time mark for logical ones and the short one for logical zeroes. The
information about the current date and time as well as some parity and status bits can be decoded
from the time marks of the 15th to the 58th second every minute. The absence of any time mark at
the 59th second of a minute indicates the beginning of a new minute with the next time mark.
Switching to MESZ or MEZ can be done automatically. The reception of the time information
is free of charge and does not need to be registered.
Figure : decoding scheme
M Start of minute (0.1 sec)
R RF transmission via secondary atenna
A1 Announcement of a change in daylight saving
Z1, Z2 Time zone identification
A2 Announcement of a leap second
S Start of time code information
P1, P2, P3 Parity bits
General information RU226
The module RU226 is mounted in a plastic case and contains the ferrite antenna and the comlete
straight receiver. Two LEDs are included for visualization of the demodulated time marks and the
field intensity of the DCF-signal. The case is delivered with a stick pad for easy mounting (e.g. on
windows/furniture). As an output-signal, the demodulated time marks are available at a four-wire
cable.