Tdev Calculations; Ffoff Calculations; Physical Description - Symmetricom TimeProvider 1000 User Manual

Chapter 1 Overview of the TimeProvider

Physical Description

You can also set thresholds using pre-defined masks according to ANSI T1.101 (for
PRS inputs), ITU-T G.811 (for PRC inputs), or ITU-T G.812 (for Type I and Type II/III
inputs). The TimeProvider performs a second MTIE calculation using the previous
24-hour period; this calculation is not used to qualify inputs.

TDEV Calculations

TDEV is a measure of the relative noisiness of an input signal that relates to its
spectral content. The TDEV for each enabled input is automatically calculated from
the previous 24-hour period. The TDEV value is used for monitoring only and is not
used for qualifying an input signal.
You can retrieve the TDEV values for the following integration times: 1, 5, 10, 100,
500, 1000, 5000, and 7200 (84000/12) seconds.

FFOFF Calculations

FFOFF is a measure of the frequency deviation of the input signal against the
system reference, expressed as a ratio. The TimeProvider automatically calculates
FFOFF for each enabled input from the 600 most recent 1-second phase updates.
You can use the automatic FFOFF calculations to qualify each input with
user-defined qualification thresholds. If an input exceeds the threshold and the
alarm level is set to Minor or higher, then the input reference automatically switches
to the next-best input.
The TimeProvider stores historical FFOFF measurements for each enabled input
every 60 seconds. You can retrieve FFOFF data for the prior 24 hours, depending
on the number of faults that have occurred.
Physical Description
The TimeProvider consists of a shelf, plug-in cards, connector adapter panels for
the cards, cables, hardware, and software. The TimeProvider is available in two
configurations: front access (Model 1000) and rear access (Model 1100), as shown
in Figure 1-1
Figure 1-4 illustrates the location of the connectors, cards, and modules in the
TimeProvider 1000.
26 TimeProvider User's Guide
and Figure 1-2.
097-58001-02 Revision C – August 2005