5: Function Reference
F5 – Time-Quality Setup
Use function F5 to enable/disable time quality reporting, and to set the thresholds of the four
time-quality flags.
How time quality reporting works: If the GPS timing reference becomes unavailable to
discipline or steer the oscillator, the oscillator begins to drift and gradually accumulates time
error. The XL-GPS estimates time error based on the oscillator-type and on the degree of
steering (the DAC value) that was being applied to the oscillator before the timing reference
became unavailable. As the estimated time error grows, exceeding the threshold of the four
Time Quality Flags
set in F5, the XL-GPS outputs four corresponding
time quality characters
in text outputs of F8. (See
“F8 – Continuous Time Once-per-Second” on page 60
)
In addition, a time quality indicator is encoded in the time codes that carry time quality
information (i.e. IRIG, IEEE 1344). (see
“F90 – Code Output Configuration” on page 105)
.
The XL-GPS accepts threshold values from 200 nS to 40000000000 nS.
The factory settings for F5 are as follows:
•
Time quality reporting - enabled
•
First time quality flag 1,000 ns
•
Second time quality flag 10,000 ns
•
Third time quality flag 100,000 ns
•
Fourth time quality flag 1,000,000 ns
See "Factory Default Jumper and Switch Settings for Options" on page 166
Related topics (Time Error):
•
“F13 – Time Error” on page 67
displays the current time error
•
“F71 – Oscillator Statistics” on page 92
provides the DAC value
Command Line
To determine if the time quality characters are enabled and what the thresholds are, enter:
F5<CR>
XL-GPS responds:
F5<S><STATE><SEP><FLAG><SEP><FLAG><SEP><FLAG><SEP><FLAG><CR><LF>
where:
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098-00116-000 Rev. A
Summary of Contents for XL-GPS
Page 1: ...XL GPS Time Frequency Receiver User Guide CD Part Number 098 00116 000 Rev A 5 May 2010 ...
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Page 225: ...J Declaration of Conformity See the following document 098 00116 000 Rev A Page 208 of 221 ...