Symmetricom XLi IEEE 1588 - Manual (Page 52)

44 XLi IEEE 1588 Clock
997-01510-03, Rev. C, 12/12/2006
S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S
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The XLi estimates the time error based on the oscillator-type and on the degree of steering (DAC value)
applied to the oscillator before the reference source became unavailable. As time error grows and
exceeds the thresholds of each time-quality flag, the XLi generates a different time-quality indicator. The
time-quality indicator is represented as a time quality character in the following text-based time outputs:
• “F8 - Continuous Time Once-per-Second” on page 46
• “F9 - Time On Request” on page 49
In addition, a time quality indicator is encoded in IRIG-B time code generated by the following functions:
• “F90 – Code Output Configuration” on page 78
For more information on time quality indicators, see “IRIG Standard Format A” on page 192 .
The XLi 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 150 ns
• Second time quality flag 15,000 ns
• Third time quality flag 1,000,000 ns
• Fourth time quality flag 150,000,000 ns
The IEEE 1588 stratum of the PTP master is determined from the following relational table based on the
XLi time quality flag settings:
• Stratum 1: 150 ns or better (GPS equivalent performance)
• Stratum 2: From 150 ns to better than 15,000 ns
• Stratum 4: From 15,00ns to better than 150,000,000 ns
Related topics (Time Error):
• “F13 – Time Error” on page 52 displays the current time error
• “F71 – Oscillator Statistics” on page 67 provides the DAC value
Command Line
To determine if the time quality characters are enabled and what the thresholds are, enter:
F5<CR>
XLi responds The XLi responds:
F5<S><STATE><SEP><FLAG><SEP><FLAG><SEP><FLAG><SEP><FLAG><CR><LF>