Tektronix CTS 850, User Manual

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Basic Test Procedures
CTS850 SDH/PDH Test Set User Manual
3–31
Video Timing Quality Testing
Compressed digital video signals transmitted over a network can be
impaired by low-frequency jitter or frequency drift that may be
acceptable in other applications. One source of this jitter is pointer
movement used to synchronize SDH payloads across a network. You
can use the CTS850 to analyze jitter in a PDH signal due to pointer
movement in the SDH signal. Two new measurements, Frequency
Drift Rate and Pointer Hit Seconds, help show this effect.
The CTS850 generates a SDH signal containing a sequence of
pointer movements. The CTS850 analyzes the timing of the dropped
34 Mb/s signal.
1. Connect the CTS850 to the network element as shown in
Figure 3–11.
CTS 850 SDH/PDH Test Set
STM-1
34 Mb/s
34 Mb/s
Add/Drop Mux
Figure 3–11: Setup to Check Video Timing Quality