Meinberg GPS163TDHS - Manual (Page 9)

9
DCF77 emulation
The GPS163TDHS satellite controlled clock generates time marks which are compa-
tible with the time marks spread by the German long wave transmitter DCF77. If
configured in GPSMON32, these time marks are available as pulse outputs. In
addition, an AM-modulated carrier frequency of 77.5kHz is available at a BNC-
connector in the front panel. This signal can be used as a replacement for a DCF77-
antenna.
The long wave transmitter installed in Mainflingen near Frankfurt/Germany trans-
mits the reference time of the Federal Republic of Germany: time of day, date of
month and day of week in BCD coded second pulses. Once every minute the complete
time information is transmitted. However, GPS163TDHS generates time marks
representing its local time as configured by the user, including announcement of
changes in daylight saving and announcement of leap seconds. The coding sheme is
given below:
M Start of Minute (0.1 s)
R RF Transmission via secondary antenna
A1 Announcement of a change in daylight saving
Z1, Z2 Time zone identification
Z1, Z2 = 0, 1: Daylight saving disabled
Z1, Z2 = 1, 0: Daylight saving enabled
A2 Announcement of a leap second
S Start of time code information
P1, P2, P3 Even parity bits
0
10
20
30
40
50
R
M
1
4
2
1
20
10
8
4
2
1
P
2
2
0
1
0 8 4 2 1
2
4
8
10
1
2
4
8
10
2
0
4 0
8
0
P
3
A1
Z1
Z2
A2
S
1
2
4
8
1
0 2 0 4
0 P
1
Minute
(reserved)
Hour
Day of Month
Day of Week
Year of the Century
Month of Year
Time marks start at the beginning of new second. If a binary "0" is to be transmit-
ted, the length of the corresponding time mark is 100 msec, if a binary "1" is
transmitted, the time mark has a length of 200 msec. The information 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.