3M
™
Advanced Systems Tester 900AST Series
45
TDR Controls
The controls described below are valid for all
modes, except for the Memory mode. The 900AST
tester displays the controls and other parameters at
the bottom of the screen.
Use the
and
key to move forward or
backward through the TDR controls. Use the
and
key to change the parameters for the
control selected.
Individual controls and their parameters are
described as follows:
Length
192” (16 ft), 384” (32 ft), 624” (52 ft), 1320” (110
ft), 2640” (220 ft), 3840” (320 ft), 5760” (480 ft),
15360” (1280 ft)
Length allows you to set the distance (or span) from
the left side of the screen to the right side. The left
side of the screen is at the end of the test leads, and
the right side is the farthest distance that can be
displayed with the selected length.
Note: The length ranges are nominal and based
on a Vp of 0.67. If you change the Vp or select a
conductor type that has a Vp other than 0.67, the
distance indicator at the right side of the display will
have a different value than the nominal length. It
will represent the actual distance displayed across
the horizontal axis of the screen for the selected Vp.
Filter
Out, In
Filter allows you to switch in a filter to remove
noise. You should use the filter if you see noise on
the display. Note that switching in the filter may
make it difficult to detect small events on the cable.
