Symmetricom TimeSource 3000, Manual, Page: 15 / 238

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TimeSource 3000
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Description
097-72000-02 Issue 6: October 2003
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Functional Description
Overview
Figure 2 shows the main functions of the TimeSource 3000. The center of the TimeSource
3000 is the Ensemble Timing Generator, which uses the BesTime algorithm to analyze the
phase and frequency relationships, individually and collectively, of the timing sources. Each
type of timing source has a particular characteristic that gives it an advantage over other
sources, as listed in Table A.
The BesTime algorithm uses the best characteristic of each source to produce an output
signal with greater overall accuracy and stability than any single source. The contribution of
a source is based on its deviation from the weighted average of all the sources. The more
accurate a source, the more weight it has in the final output. Every source is under constant
evaluation and its contribution subject to periodic adjustment. The output is essentially the
best performance of the best source.
Table A. Timing Source Characteristics
Source Characteristic
Local Oscillator Short term stability
T1 Line Intermediate term stability
External Oscillator Intermediate term stability
GPS Signal Long term stability