R T M 3 2 0 4 G P S T i m i n g M o d u l e U s e r M a n u a l
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"Smarter Timing Solutions"
Appendix
E
Timecode Formats
A standard feature of your RTM3204 GPS Timing Module is a single timecode output available at the
rear panel SMB connector identified as AM CODE
The output code format is selectable via a console command. See
cpuopt
s
in
Chapter 3 - Control
and Status Commands
. Each format is described below. Time codes are commonly used to provide
time information to external devices such as displays, magnetic tape devices, strip chart recorders
and several types of embedded computer peripheral cards.
IRIG-B122
This is the most widely used format and is normally the factory default for the AM Code output. The
IRIG-B122 format is a 100 pps code and is used to amplitude modulate a 1000 kHz sine wave carrier.
The information contained in the timecode is seconds through day-of-year coded in Binary Coded
Decimal (BCD). Reference IRIG Document 104-60.
IRIG-B123
In addition to the time information identified in B122 above, this format also contains Straight Binary
Seconds (SBS) of day. SBS is provided at the end of the frame, in the 17 bits starting in position 80.
IEEE-Standard 1344-1995
This standard provides for the addition of time/status data in the control bit positions of IRIG-B. The
information provided there is: Unit and Tens of Years, Leap Second, Daylight Savings, Local Time
Offset, Time Quality and Parity. The IEEE-1344 table provided below shows each bit position with
detailed information.
NASA-36 Bit
NASA-36 bit time code is a 100-bit, pulse width modulated format used to amplitude modulate a
1000 kHz sine wave carrier. The information contained in the timecode is seconds, minutes, hours
and days. The format is used by several military ranges. Reference IRIG Document 104-59.
2137
The 2137 code is a 25-bit pulse width modulated format used to amplitude modulate a 1000 kHz sine
wave carrier. The information contained in the timecode is seconds, minutes and hours. The format
is used by certain security organizations.
Summary of Contents for RTM3204
Page 1: ...Smarter Timing Solutions RTM3204 GPS Timing Module User Manual...
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