Meinberg TCR511PCI, Руководство пользователя

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3 Introduction: Abstract of Time Code
The transmission of coded timing signals began to take on widespread importance in the early 1950s. Especially
the US missile and space programs were the forces behind the development of these time codes, which were used
for the correlation of data. The denition of time code formats was completely arbitrary and left to the individual
ideas of each design engineer. Hundreds of dierent time codes were formed, some of which were standardized
by the "Inter Range Instrumentation Group" (IRIG) in the early 60s.
Except these "IRIG Time Codes" other formats, like NASA36, XR3 or 2137, are still in use. The board &PROD-
UCT however only decodes IRIG-A, IRIG-B or AFNOR NFS 87-500 formats. The AFNOR code is a variant of
the IRIG-B format. Within this code the complete date is transmitted instead of the "Control Functions" of the
IRIG telegram.
3.1 Description of IRIG-Codes
The specication of individual IRIG time code formats is dened in IRIG Standard 200-04. They are described by
an alphabetical character followed by a three-digit number sequence. The following identication is taken from
the IRIG Standard 200-98 (only the codes relevant to TCR5xx are listed):
character bit rate designation A 1000 pps
B 100 pps
1st digit form designation 0 DC Level Shift width coded
1 sine wave carrier amplitude modulated
2nd digit carrier resolution 0 no carrier (DC Level Shift)
1 100 Hz, 10 msec resolution
2 1 kHz, 1 msec resolution
3 10 kHz, 100
µ
sec resolution
3rd digit coded expressions 0 BCD, CF, SBS
1 BCD, CF
2 BCD
3 BCD, SBS
BCD: time of year, BCD-coded
CF: Control-Functions (user dened)
SBS: seconds of day since midnight (binary)
TCR511PCI Date: 2009-06-24 3