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Precision
Test Systems manufacturers several timing products.
These include:
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GPS10RBN
Frequency Standard. Options for this product
include IRIG-B, IRIG-E, BCD and 1 pps timing
outputs.
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GPS10RBN-16 BCD Timer Unit. This unit
generates a BCD (binary coded decimal) output with
100 ns resolution and typically 100 ns accuracy to UTC world time. It is usually used with the
GPS10RBN Frequency Standard but can be used as a
stand alone model as well. The BCD timer
output is in the form HH:MM:SS.sssssssss where HH is
hours, MM is minutes, SS is seconds and ss is
decimal seconds to 100 ns resolution.
Time
Codes, generally in serial form, are used to convey time
information from one point to another. Many different
time code formats have been developed over the years, by
both commercial and military agencies. Many of our
products support one or more of these time codes as a
standard feature; we can also address less common
formats on a
custom
basis. Here is a description of the more common formats:
BCD
Time Code
BCD or binary coded
decimal is an old fasion time code but still in use
today by some companies. Precision Test Systems is
unique in it provides a ultra high resolution BCD time
code. The format is HH:MM:SS.sssssssss, where H is
hours, M is minutes, S is seconds and s is decimal
seconds. Resolution of oure BCD time code is 100
ns and accuracy can be as accurate as plus/minus 200 ns.
ESE
Time Code™
ESE
Time Code™ was originally developed in the mid 70's as
an inexpensive way to send time of day to remote digital
slave displays. The original format, TC76™, was capable
of sending six digits of time data, or four digits of
elapsed timer data (using a slightly altered bit
format). The time can be sent in 12 or 24 hour format.
No AM/PM data is sent in 12 hour mode, however. The
newer, TC89™ time code adds two bits of information to
convey AM/PM and display mode information. TC89 is
compatible with old non-microprocessor slaves, although
the older slaves don't recognize the mode bits.
Subsequent to this, TC90™ time code was developed to
take advantage of the new microproceesor based slaves.
It is not compatible with the old slaves, but provides
both Time and Date, and Auxiliary data when required.
The ES160A and ES185A provide both TC89 and TC90 codes
on separate connectors. With a few exceptions, TC89 is
the standard output on most other products which feature
ESE output.
SMPTE / EBU Time Code
SMPTE / EBU time code
is used by the video & audio industries for providing
frame-accurate time references for editing video & audio
tape, or as a master time reference for radio / TV
stations. When used for editing, the code is typically
recorded on a spare audio or time code track on the
tape. SMPTE (Society of Motion Picture & Television
Engineers) code runs at 29.97 frames/second; EBU
(European Broadcasting Union) code runs at 25
frames/second. These codes send Hour, Minute, Second and
Frame data. These codes are basically audio in nature.
Another variety of these editing codes known as "VITC"
(Vertical Interval Time Code or "vit-see") is video in
nature; it is recorded on unused lines in the Vertical
Interval of the video signal. ESE manufactures a number
of VITC products, primarily for military clients; we can
support VITC for other applications on a
custom
basis.
IRIG
Time Codes
The Inter-Range
Instrumentation Group codes, originally developed for
sending time or other data around missile test ranges,
finds use in government, military and commercial fields.
These digital codes are typically amplitude modulated on
an audio sine wave carrier (though not always). The most
common version is IRIG-B, which sends Day of Year, Hour,
Minute and Second data on a 1000 Hz carrier, with an
update rate of one second. Other "IRIG" codes, as well
as related codes such as "NASA", "XR3" and "2137" can be
supported on a
custom
basis.
ASCII Time Code
ASCII Time Code is simply time data sent in serial ASCII
form using either an RS-232 or RS-422 interface. It is
typically used for interfacing time data to a computer
(ESE provides software for synchronizing the clock of a
PC computer to ESE Master Clocks). The data format &
baud rate can vary depending on the product or intended
application. For example, the format sent by the ES-160A
and ES-185/185A, if displayed directly on a computer
terminal, would appear thus:
04-18-96 109:12:57:15
This data is sent once
per second at 9600 baud using an RS-232 interface; it
transmits Month-Day-Year, Day-of-Year, Hour, Minute &
Second.
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