Divide the loss obtained by the cable length and obtain the pulse attenuation loss in dB per
metre or per foot.
Multiply by the distance reading for the cable length noted in the Return Loss measurement to
obtain the appropriate pulse attenuation.
Obtain the TRUE RETURN LOSS from:
True Return Loss = Measured Return Loss – Pulse Attenuation.
Note: Pulse Attenuation (Cable Loss) is frequency dependent and will be higher for narrow
pulse widths than wider pulse widths. The pulse width used for measuring pulse attenuation
MUST be the same as that used to measure the Return Loss.
A library of Pulse Attenuation (Cable Loss) for different cable types for different pulse widths can
be compiled using the procedure detailed in “Measurement of Pulse Attenuation”.
7.10
FILTER
A low pass filter is available from the Help menu. It is used to reduce noise, especially on high
gain settings. It should not be used with the 2 ns and 10 ns pulses.
Radiodetection Ltd. 00901209-6
T631 OPERATING MANUAL
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