zl30109 Zarlink Semiconductor, zl30109 Datasheet - Page 15

• Manufacturer Part Number: zl30109
• Description: Ds1/e1 System Synchronizer With 19.44 Mhz Output
• Manufacturer: Zarlink Semiconductor

Examples:
HMS=1: When 10 Normal to Holdover to Normal mode transitions occur and in each case the Holdover mode was
entered for 2 seconds, then the accumulated phase change (MTIE) could be as large as 3.13 µs.
where:
-
-
-
-
-
-
REF
Output
Clock
REF
Output
Clock
REF
Output
Clock
REF
Output
Clock
Phase
Phase
Phase
0.15 ppm is the accuracy of the Holdover mode
0 ns is the maximum phase discontinuity in the transition from the Normal mode to the Holdover mode
13 ns is the maximum phase discontinuity in the transition from the Holdover mode to the Normal mode
when a new TIE corrector value is calculated.
holdover_drift
mode_change
10 changes
= 10 x (300 ns + 13 ns) = 3.13 µs
TIE_CLR=0
Normal mode
Phase drift in Holdover mode
Return to Normal mode
= 0.15 ppm x 2 s = 300 ns
= 0 ns + 13 ns = 13 ns
HMS = 0
Figure 8 - Timing Diagram of Hitless Mode Switching
Zarlink Semiconductor Inc.
ZL30109
15
REF
Output
Clock
REF
Output
Clock
REF
Output
Clock
REF
Output
Clock
TIE_CLR=0
Return to Normal mode
Normal mode
Phase drift in Holdover mode
HMS = 1
Data Sheet