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Precision Test
Systems manufacturers many types of frequency standards
and distribution amplifiers that can have optional time
codes outputs. The different types of time codes
are briefly described below.
1 pps
The 1 pps signal
is basically a 1 Hz squarewave or pulse. The
rising edge of this signal can be synchronized to UTC or
GPS time to an accuracy of 20 ns.
The output level
is normally TTL and most of our products will drive this
TTL into a 50 ohm impedance.
IRIG Time
Code
IRIG stands
for
Inter-Range Instrumentation Group and
these codes were originally designed for sending time or
other data round missile test ranges.
There are various
types, but IRIG-B has been adopted as a standard and is
used by government, military, and commercial fields.
These time codes are typically amplitude modulated on a
1 kHz sinewave or TTL. IRIG-B over RS232 is also
available.
IRIG-B sends day
or year, hour, minutes and seconds data with an update
time of one second.
Precision Test
Systems supplies IRIG-B time codes on many of its
products.
ASCII Time
Code
ASCII time code is
simply data sent over RS232 or RS485. It is
typically used for interfacing to computers. ASCII
time code is optionally available on many of our
products.
BCD Time
Code
BCD or binary
coded decimal is an old fashion format, but is still
used by some organizations. Our BCD time code is
unique in that it gives s HH:MM:SS.ssssss format
where H is hours, M is minutes and S is seconds. The
small s is fractional seconds and we offer a resolution
of 100 ns. Update time is every 100 ns and typical
accuracy to UTC is 200 ns.
Other types
of time codes
Other types of
codes include ESE time code, SMPTE time code and EBU
time code. Precision Test Systems can offer these
formats on special order.
If you need a time
format not mentioned here, then contact us to see if
this can be incorporated into our products.
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