Generated Time Codes; Selection Of Generated Time Code - Meinberg LANTIME/GPS Operating Instructions Manual

Generated Time Codes

Besides the amplitude modulated sine wave signal, the board also provides
unmodulated DC-Level Shift TTL output in parallel. Thus six time codes are
available.
a) B002:
b) B122:
c) B003:
d) B123:
e) AFNOR:
f) IEEE1344:

Selection of Generated Time Code

The time code to be generated can be selected by Menu Setup IRIG-settings or the
GPS Monitorprogram. DC-Level Shift Codes (PWM-signal) B00x and modulated
sine wave carrier B12x are always generated simultaneously. Both signals are
provided at the VG64-Connector, i.e. if code B132 is selected also code B002 is
available. This applies for the codes AFNOR NFS 87-500 and IEEE1344 as well.
The TFOM field in IEEE1344 code is set dependent on the 'already sync'ed' character
('#') which is sent in the serial time telegram. This character is set, whenever the
preconnected clock was not able to synchronize after power up reset. The 'time figure
of merit' (TFOM) field is set as follows.
Clock synchronized once after power up:
Clock not synchronized after power up:
For testing purposes the output of TFOM in IEEE1344 mode can be disabled. The
segment is set to all zeros then.
100 pps, PWM DC signal, no carrier
BCD time-of-year
100 pps, AM sine wave signal, 1 kHz carrier frequency
BCD time-of-year
100 pps, PWM DC signal, no carrier
BCD time-of-year, SBS time-of-day
100 pps, AM sine wave signal, 1 kHz carrier frequency
BCD time-of-year, SBS time-of-day
Code according to NFS-87500, 100 pps,
AM-Sine wave signal, 1kHz carrier frequency,
BCD time-of-year, complete date, SBS time-of-day,
Signal level according to NFS-87500
Code according to IEEE1344-1995, 100 pps,
AM sine wave signal, 1kHz carrier frequency,
BCD time-of-year, SBS time-of-day, IEEE1344
extensions for date, timezone, daylight-saving
and leap second in control functions (CF) segment.
also see table 'Assignment of CF segment in IEEE1344 mode'
TFOM = 0000
TFOM = 1111
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