178 TimeHub 5500 User’s Guide 097-55501-01 Revision M – January 2009
Chapter 4 Testing and Configuring the TimeHub
Testing the Clock Input Signals
Testing the Clock Input Signals
Prior to testing the clock input signals, ensure that the following has been
performed:
Each available DS1 reference is connected to the appropriate DS1 input
wire-wrap pins on the Input/Alarm Connector module:
– Terminated DS1s are connected to any of the four pins labeled “DS1
TERM IN”
– Bridged DS1s are connected to any of the four pins labeled “DS1 BRDG
IN”
The 5 MHz or 10 MHz PRS input reference is connected to the BNC connector
labeled “5/10 MHz IN”
The CC input(s) for a Remote shelf are connected to the appropriate CC In
wire-wrap pins on the Input/Alarm Connector module
Input signal level requirements for the PRS inputs, DS1 terminated inputs, and DS1
bridged inputs are covered in Chapter 6, Specifications.
To verify that the clock input signal(s) are within the specified input voltage range,
perform the following procedure using a dual-channel oscilloscope with a 100 MHz
minimum bandwidth.
1. Set the oscilloscope controls as listed in Table 4-4. Consult the oscilloscope
manufacturer’s manual for details and operating instructions.
2. Connect the X10 probes to the channel 1 and channel 2 oscilloscope inputs,
and install a terminating resistor across the probes.
3. Connect the channel 1 and 2 probe ground leads together.
4. Connect the channel 1 and 2 probes (with resistor) to T and R of each DS1
reference input on the Input/Alarm Connector module (refer to Figure 2-7).
5. Verify that the clock input signal(s) are within the specified input voltage range
and meet the prescribed template. Consult your local specifications for the type
of input signals installed and on which input connectors.
Input signal ranges are as follows:
– DS1 Terminated: 1.0 V to 3.5 V base-to-peak, 100 terminated
– DS1 Bridged: 0.10 V to 0.35 V base-to-peak, 100 terminated
– CC: 1.5 V to 4.0 V base-to-peak, 130 terminated (only used with
Remote shelf)
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