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Making Measurements
Measuring Jitter Transfer
Measuring Jitter Transfer
Description: You can perform Jitter transfer measurements at each of the four DSn
rates, STS-3, OC-3, OC-12 and OC-48. The jitter generator provides the
stimulus for the jitter transfer measurement.
Narrow band filtering is used in the jitter receiver thus allowing
selection and measurement of the relevant jitter components to provide
accurate and repeatable results.
The jitter transfer results are presented in graphical and tabular form.
Graphical results are plotted as Gain V Frequency.
The relevant Pass Mask (ITU-T G.823 for DSn, ITU-T G.958 and Bellcore
GR-253 for SONET) is also displayed on the graph.
NOTE 1.The Transmitter and Receiver must be set to the same interface rate.
HOW TO: Achieve the required accuracy:
1 The HP 37718A must be connected back to back in order to perform a
calibration cycle before making a Jitter Transfer measurement.
2 The HP 37718A must have been switched on for 1 hour before starting
a calibration cycle.
3 The climatic conditions must remain stable from switch-on to end of
measurement.
4 The Jitter Transfer measurement must be started within 10 minutes
of completion of the Calibration.
5 If maximum Delay time, maximum Dwell time and maximum number
of Points is selected, the accuracy specification cannot be guaranteed
as the time from start of calibration to end of measurement (test
period) will be approximately two hours. It is recommended that the
maximum test period does not exceed 90 minutes.
Test Period = Delay Time + Dwell Time + 5 Seconds X Number of
Points X 2 (Calibration + Measurement).
NOTE For best results, a Dwell Time of 20 seconds and a Delay Time of 10
seconds, are recommended.