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NTC TDR
The NTC TDR identifies the precise distance to micro-reflection problems and
impedance mismatches in the plant. It is used as a field tool to locate problems
identified from PNM initiatives. The NTC TDR is completely different from any other
existing TDR. The NTC TDR calculation of the time distance and corresponding physical
distance to the impedance mismatch is based on an autocorrelation process which
utilizes very low level non-intrusive spread spectrum signals transmitted at return path
frequencies in the forward. It is effective from the connection point to the next amplifier.
An illustration of how the device operates and is connected to the network is provided
in the figure below. Here a spread spectrum signal is input through an amplifier return
in test port, the signal travels through the network to the next amplifier (where due to
the presence of the diplex filter the probing signal can go no further), and signals are
reflected back at all points not having a perfect 75 ohm match and the reflected signal
is detected and measured at a second return out test port. (For simplification only one
reflected signal is shown.)
Active Radar warning message
