MT9045 Zarlink Semiconductor, MT9045 Datasheet - Page 14

• Manufacturer Part Number: MT9045
• Description: T1/E1/OC3 System Synchronizer
• Manufacturer: Zarlink Semiconductor

Phase Lock Time
This is the time it takes the synchronizer to phase lock to the input signal. Phase lock occurs when the input signal
and output signal are not changing in phase with respect to each other (not including jitter).
Lock time is very difficult to determine because it is affected by many factors which include:
•
•
•
•
Although a short lock time is desirable, it is not always possible to achieve due to other synchronizer requirements.
For instance, better jitter transfer performance is achieved with a lower frequency loop filter which increases lock
time. And better (smaller) phase slope performance (limiter) results in longer lock times. The MT9045 loop filter and
limiter were optimized to meet the AT&T TR62411 jitter transfer and phase slope requirements. Consequently,
phase lock time, which is not a standards requirement, may be longer than in other applications. See AC Electrical
Characteristics - Performance for Maximum Phase Lock TIme.
initial input to output phase difference
initial input to output frequency difference
synchronizer loop filter
synchronizer limiter
Zarlink Semiconductor Inc.
MT9045
14
Data Sheet