As the measured distance is taken at the start of the reflected
pulse, the size of the pulse width does not affect the accuracy
of the measurement. However, if the first feature does not give
a complete reflection such that the instrument can see beyond
it to a second feature, the ability to discern between features is
affected by the pulse widths. If there are multiple features, the
instrument can only fully discern between them if the features
are more than the pulse width apart. Hence, for discerning
multiple features, the instrument should be used with the
smallest pulse width that can see both features.
When using the RANGE key to change the instrument’s range,
the pulse widths are set to the instrument’s default for that
range. If the attenuation of the C.U.T is too high or there are
multiple cable features which the default pulse width can not
discern between, the user can override the default by entering
the CONFIG Options menu.
Memory Features
The TDR2000 has 15 memory locations, which can be used to
store traces from previously tested cables. These may be
stored for future analysis or be downloaded to the
TRACEMASTER software for analysis on a PC. Each memory
location stores the graphical trace along with the gain, range
and mode settings. With the TRACEMASTER software, the
stored trace can be annotated and kept on file for future
reference. You can also upload a trace to the instrument using
the TRACEMASTER software, including the first 64 characters
of any annotation applied to that trace.
With the extensive dual trace and difference modes available to
the TDR2000, memory locations can be used as comparisons
for live traces. This is useful if the known good cores that would
normally be used in the [L1]-[L2] mode are two far away from
the C.U.T. Instead, a memory trace of a known good cable can
be compared against the C.U.T.
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