pdhman.book : pdhapp.doc 44 Tue Oct 14 15:00:20 1997
44
PDH / DSn Testing With The HP 37717C
FAS Monitoring
FAS Monitoring
Options Required Structured PDH UKJ (USA) or UKN (USE), or Unstructured
PDH UKK (USB)
Alternatively for PDH / DSn with ATM payloads Option UKZ.
NOTE Option UKK (USB) - Unstructured PDH allows FAS Monitoring to be carried out at
2, 8, 34 and 140 Mb/s.
Option UKZ - allows FAS Monitoring to be carried out at DS1 and DS3 (Incorrect F
and M framing sequence) rates as well as at 2 and 34 Mb/s ETSI rates.
Application
Degradation in error performance can be detected by the occurrence of Frame
Alignment Signal (FAS) errors in PDH /DSn systems.
Using the HP 37717C in a receive only mode, FAS errors can be measured and
viewed on the display. In addition, the results can be logged on the
selected logging device for examination later.
Default (Known State) Settings
It can be advisable to set the HP 37717C to a known state prior to setting up to make
a measurement. This clears all previous settings and provides a clearly defined
instrument state. For a list of Default Settings and the procedure for accessing them
see Stored Settings.
Test Setup Procedure (FAS Monitoring)
This setup procedure is based on Structured PDH 140 Mb/s line traffic interfaced at
the line equipment protected Monitor point. If a protected Monitor Point is not
available then an HP 15510A Protective Probe may be used at an unprotected
Monitor point.
The instrument is used in a receive only mode to measure FAS Errors. A Timed Start
test period is used which allows the measurement to be started at a time when the
user would not normally be available.
All Error Ratio and Analysis results are logged on the selected logging device at 2
hour intervals and at the end of the test period. Occurrences of error seconds and
RESULTS
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