Aim AXC-FDX-2, Hardware Manual

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3 . Structure of the AXC-FDX-2
AXC-FDX-2 Hardware Manual 12
3.1.3 IRIG- and Time Code Section
The main functions of the Time Code Processor (TCP) are:
a. IRIG-B compatible Time Code Decoder function
b. Time Code Encoder
– IRIG-B compatible Time Encoder function
3.1.3.1 IRIG-B Synchronization Unit
The supported IRIG Time Code Format is B122.
B Bit Rate =100Hz, Bit Time = 10ms,
Bits/Frame =100, Frame Time = 1000mS, Frame Rate = 1Hz
1 Modulation type=Sine wave Carrier, amplitude modulated
2 Carrier Frequency = 1kHz (1ms resolution)
2 BCD coded
The time code information can be used for time-tagging and multi-channel
synchronization.
3.1.3.2 Timecode Encoder/Decoder
On the AXC-FDX-2 a freewheeling IRIG function is implemented. If no external IRIG
signal is detected, the IRIG Decoder switches automatically to the freewheeling
operation mode. If an external IRIG-B signal is detected in freewheeling mode, the Time
Tag is automatically synchronized to this external IRIG-B signal.
The time tag on the board is generated in the format shown below.
Time Element Number of bits
DAYS of year 9
HOURS of Day 5
MINUTES of Hour 6
SECONDS of Minute 6
MICROSECONDS
of Second 20
100ns of Microsecond 4
Summary 50 (7 Bytes, stored in two 32bit words)
Table 3-1 Time Tag Format