Symmetricom 1000 User Manual

Chapter 7 Specifications of the TimeProvider
Inputs

196  TimeProvider User’s Guide

 lists the default values for the Hold-in range and Pull-in range for the 

Clock cards available for the TimeProvider. 

According to GR-1244, hold-in is the process by which an NE and its clocks 
maintain lock to the active reference as the frequency of that reference varies 
arbitrarily slowly. Thus, the hold-in range is the largest band of input signal 
frequency for which the NE and its clocks will maintain lock. As is the case for the 
pull-in range, the hold-in range is generally specified so that an NE/clock of a given 
stratum level will maintain lock with a reference that is traceable to a clock of the 
same stratum level. 

According to GR-1244, pull-in is the process during which an NE's clocks become 
locked to a reference. In turn, an NE's pull-in range is the largest band of input 
reference signal frequency for which its clocks will acquire lock. In general, pull-in 
requirements are intended to assure that any NE/clock will always be able to lock to 
a reference signal that is traceable to a clock of equal (or higher) quality. Therefore, 
for a given stratum level the minimum pull-in range is generally the same as the 
maximum acceptable free-run frequency offset.

Front Access and Rear Access shelves contain three card slots: two for IOC cards 
and one for an IMC or integrated IMC/TPIU card.

Each IOC supports three input ports: two span inputs and one PRS input.

PRS Input port: 2048 kHz G.703/13, 1.544/5/6.312/10 MHz sine or square

Input ports 1 and 2: 2048 kbit/s,G.703/9, 2048 kHz G 703/13, DS1, 
1.544/5/6.312/10 MHz sine or square, CC/JCC/JCC4 composite clock

Type I (Quartz IOC only)

9.8 E-6

9.3 E-6

Type II/ST2 (Rb IOC only)

4.0 E-8

3.5 E-8

Type III/ST3E (Quartz IOC only)

9.8 E-6

9.3 E-6