SCTE 03 2003

The purpose of this procedure is to provide instructions to measure cablestructural return loss (SRL). There are two test methods presented, as theaccuracy, ease-of-use, and required test equipment differs for each testmethod. The two methods, with their major advantages anddelinquencies, are described below:

Fixed Bridge Method: The cable impedance as a function of frequencyis calculated from a vector (magnitude and phase) return loss. Theaverage of this impedance across the desired frequency range is the.cable reference impedance.. The structural return loss is calculatedfrom the cable impedance as a function of frequency and the cablereference impedance. This may be automated, but requires a vectornetwork analyzer, and may be subject to errors due to the cableconnectionVariable Bridge Method: The return loss of a cable is measured, whilevarying the impedance of a reflection bridge, until the return loss isminimized. This method requires simple, magnitude only (scalar)measurements, but is subject to errors from the cable connection, andoperator skill.

Fixed Bridge Method: The cable impedance as a function of frequencyis calculated from a vector (magnitude and phase) return loss. Theaverage of this impedance across the desired frequency range is the.cable reference impedance.. The structural return loss is calculatedfrom the cable impedance as a function of frequency and the cablereference impedance. This may be automated, but requires a vectornetwork analyzer, and may be subject to errors due to the cableconnection

Details

Published:

01/01/2003

ANSI:

ANSI Approved

Number of Pages:

13

File Size:

1 file , 210 KB