No Output Or Outputs; Noisy Outputs; Incorrect Frequencies; T1 Telecom Interface Output (87-6000T1-8) - Symmetricom XLi User Manual

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The possible causes for these symptoms are discussed by the following sections.

No Output Or Outputs

Before assuming a clock malfunction, first check that the instrument using the output is functioning
properly. Verify that all connectors are secure and coax cables are good. If at least one output is
functioning, the problem may be a bad option assembly.If all outputs have failed, the problem may be a
bad option assembly, a bad Backplane Bus Assembly, a bad Processor Assembly, or bad connections
between these assemblies.

Noisy Outputs

If the outputs are noisy or intermittent, the problem may be a bad option assembly, a bad Processor
Assembly, a bad backplane Bus Assembly, or bad connections between these assemblies.

Incorrect Frequencies

If the frequency is out of specification, the system clock may have lost lock with the reference source
(i.e., GPS satellite signal) for a long period of time or the problem may be incorrect firmware installed on
the Processor Assembly.
Sine Wave Amplitude Adjustment
Set the amplitude of the 1, 5, and 10 MHz outputs to 1 Vrms into a 50 Ω load, by adjusting pots [R9, R15,
and R17], respectively, on the 1, 5, 10 MHz/MPPS card.

T1 Telecom Interface Output (87-6000T1-8)

Introduction

The T1 Output Card card generates telecommunications timing signals that comply with ITU T G.703
and ITU T G.704 standards for 12-Frame Multiframe (D4 or SuperFrame) and 24-Frame Multiframe
(ESF or Extended SuperFrame). In addition, when the XLi is configured with an appropriate high stability
oscillator option, it meets the requirements of ANSI T1.101-1994 and ITU-T G.811 for Primary Reference
Clock operation.
The card is a single-height plug-in option card. All of its output signals are balanced and provided
through panel-mounted wire wrap pins. Two sets of Form-C relay closures are also included for major
and minor alarm indications. These closures are accessible on the panel-mounted wire wrap pins.
Figure 11: Wire-wrap outputs on the T1 card
XLi Time & Frequency System
XLi-man, Issue 8, 6/17/2008, Rev. H
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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