Meinberg TCR509 - Manual (Page 10)

10
The DCF Simulation Mode
In DCF-Simulation mode the TTL and current loop outputs provide a time mark signal
similar to the signals transmitted by the german VLF time code transmitter DCF77.
Within one minute a complete time code frame is transmitted. Since there are no
timezone and leap second announcements in the IRIG time code, these announcement
flags (daylight saving flag, leap second flag) are neglected. The generated DCF telegram
always contains the time information which is derived from the IRIG Signal and the
system clock. When receiving a time code telegram containing a leap second ( field sec.
is 60 ) the DCF simulation is turned off for a minute. By this the re-synchronization of all
clocks connected to the simulation outputs is enforced. The issued DCF time code frame
contains a date information which is derived from the system clock. The validity of the
system clock date is ensured by a 'day of year' comparison. In case of an invalid system
clock date the DCF simulation is turned off. System clocks initial date can be set via
COM0. In case of brown out or power failure a lithium battery guarantees the system
clocks operation for at least ten years. ( Option: Gold Cap buffering for 150 hours )
M Start of Minute (0)
R RF Transmission via secondary antenna (0)
A1 Announcement of a change in daylight sa-
ving
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 (1)
P1, P2, P3 Even parity bits
TIME_SYN Output
This TTL-Output, which is provided at the 64Pin VG Connector, turns high as soon
as valid time code telegrams are received. Whenever a faulty telegram is detected or the
reception fails completely ( due to a broken wire e.g. ) the TIME_SYN output turns low.