Spectracom NetClock 9400 Series, User Reference Manual

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device than does an IRIG AM (Amplitude Modulation) signal. This is due to the faster rise-time
with the DCLS signal being able to provide a more “crisp” on-time point (more distinct, with
less jitter) than the slower rise-time of an AM modulated signal.
IRIG AM synchronization of a device to its IRIG source is typically measured in the tens of micro
seconds, while synchronization using a IRIG DCLS signal can typically provide around 100
nanoseconds or so (plus the cable delays between NetClock and the other device, as well as
the processing delays of the other system itself).
Note that each of the four IRIG outputs of the Model 1204-15 card has its own available ‘offset’
capability, which is configurable via NetClock’s Web UI, to help account for cabling and pro
cessing delays of the device each output is connected with.
5.5.2 IRIG Carrier Frequencies
Each IRIG code specifies a carrier frequency that is modulated to encode date and time, as well
as control bits to time-stamp events. Initially, IRIG applications were primarily military and gov
ernment associated. Today, IRIG is commonly used to synchronize voice loggers, recall record
ers, and sequential event loggers found in emergency dispatch centers and power utilities.
Table 5-13:
Available IRIG output signals
Format Encoding Modulation Carrier Coded Expressions Bit rate
Time Frame Inter
val
IRIG-A
IRIG-A A000 DCLS N/A BCD
TOY
, CF and SBS 1000 pps 0.1 sec
IRIG-A A001 DCLS N/A BCD
TOY
, CF 1000 pps 0.1 sec
IRIG-A A002 DCLS N/A BCD
TOY
1000 pps 0.1 sec
IRIG-A A003 DCLS N/A BCD
TOY
, SBS 1000 pps 0.1 sec
IRIG-A A004 DCLS N/A BCD
TOY
, BCD
YEAR
, CF and
SBS
1000 pps 0.1 sec
IRIG-A A005 DCLS N/A BCD
TOY
, BCD
YEAR
, and CF 1000 pps 0.1 sec
IRIG-A A006 DCLS N/A BCD
TOY
, BCD
YEAR
1000 pps 0.1 sec
IRIG-A A007 DCLS N/A BCD
TOY
, BCD
YEAR
, and
SBS
1000 pps 0.1 sec
IRIG-A A130 AM 10 kHz BCD
TOY
, CF and SBS 1000 pps 0.1 sec
IRIG-A A131 AM 10 kHz BCD
TOY
, CF 1000 pps 0.1 sec
IRIG-A A132 AM 10 kHz BCD
TOY
1000 pps 0.1 sec
414 NetClock User Reference Guide
APPENDIX