Historical
ANSI/SCTE 66 2008
Test Method For Coaxial Cable Impedance
1.1. The purpose of this procedure is to provide instructions for measuring cable impedance. Two test methods are presented. The accuracy, ease of use, and required test equipment differ for each test method. The two methods are as follows:
1.2. Variable bridge method: The return loss of a cable is measured, while varying the impedance of a reflection bridge. The value of impedance, which gives the minimum reflection, is the average cable impedance. This method requires simple, scalar (magnitude only) measurements. It is subject to errors from the cable connection and operator skill.
1.3. Fixed bridge method: The cable impedance as a function of frequency is calculated from a vector (magnitude and phase) return loss. The average of this impedance across the desired frequency range is the cable impedance. This may be automated, but requires a vector network analyzer, and may be subject to errors due to the cable connection.
Content Provider
The Society of Cable Telecommunications Engineers [scte]
