3M
™
Advanced Systems Tester 900AST Series
46
Vp (Velocity of Propagation)
0.10 to 0.99
Vp allows you to adjust the velocity factor
(“propagation velocity”) of the conductor or pair.
Different conductors have different values of Vp.
To get the most accurate distance, Vp should be set
to the exact value for the conductor being tested.
The 900AST tester Setup Menu pre-selects Vp
values based on the type of circuit being tested. The
propagation velocity is shown in the left-side box at
the top of the TDR screen.
Pulse Width
3 ns, 5 ns, 34 ns
Pulse Width allows you to select the width of the
pulse sent out on the circuit. The 900AST tester
automatically chooses the best pulse width for each
length selected. Note that you can change the pulse
width independent of the length.
Use a shorter pulse width to give better resolution
of events. A shorter pulse will not go as far on the
circuit. Use a longer pulse to see farther on the
conductor. Note that the resolution of a longer pulse
will not be as good as a shorter pulse.
The pulse width is shown in the right-side box at the
top of the TDR screen.