METHOD FOR PERFORMING A SHIELD INTEGRITY TEST AND FOR ISOLATING TROUBLE IN THE SHIELD USING GRAPHICAL ANALYSIS
First Claim
1. A method for detecting the integrity of a cable shield of a distribution cable carrying telecommunication services to a subscriber, the distribution cable having a first end proximate a connection box, a second end opposite the first end, a plurality of pairs of conductors, each pair of conductors including a tip and a ring, and a shield;
- the method comprising the steps of;
identifying a pair of conductors;
shorting and grounding first ends of the tip and ring of said identified pair of conductors;
providing a test instrument having a plurality of leads;
electrically connecting a first lead of said test instrument to the second end of the tip;
electrically connecting a second lead of said test instrument to the second end of said ring;
electrically connecting a third lead of said test instrument to the shield of said cable, the shield of said cable electrically connected to ground;
utilizing said test instrument to measure a loop resistance of the identified pair;
utilizing said test instrument to calculate an expected pair loss of the identified pair based upon said measured loop resistance of the identified pair;
utilizing the test instrument to identify a modem output power level;
utilizing the test instrument to calculate a predicted signal level;
utilizing said test instrument to measure a wideband noise-to-ground on the identified pair;
utilizing said test instrument to calculate a predicted noise metallic based on said measured wideband noise-to-ground and a minimum expected pair balance;
utilizing said test instrument to calculate and display a predicted signal-to-noise ratio based on said predicted signal level and said predicted noise metallic.
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Accused Products
Abstract
A method for evaluating the integrity of a cable shield utilizing wideband noise-to-ground measurements is provided. Upon determining that trouble with the cable shield exists, a method s is provided to isolate the location of the trouble with the cable shield. The method utilizes access locations along the cable and therefore does not require opening of the cable shield to isolate the trouble in the shield.
23 Citations
26 Claims
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1. A method for detecting the integrity of a cable shield of a distribution cable carrying telecommunication services to a subscriber, the distribution cable having a first end proximate a connection box, a second end opposite the first end, a plurality of pairs of conductors, each pair of conductors including a tip and a ring, and a shield;
- the method comprising the steps of;
identifying a pair of conductors; shorting and grounding first ends of the tip and ring of said identified pair of conductors; providing a test instrument having a plurality of leads; electrically connecting a first lead of said test instrument to the second end of the tip; electrically connecting a second lead of said test instrument to the second end of said ring; electrically connecting a third lead of said test instrument to the shield of said cable, the shield of said cable electrically connected to ground; utilizing said test instrument to measure a loop resistance of the identified pair; utilizing said test instrument to calculate an expected pair loss of the identified pair based upon said measured loop resistance of the identified pair; utilizing the test instrument to identify a modem output power level; utilizing the test instrument to calculate a predicted signal level; utilizing said test instrument to measure a wideband noise-to-ground on the identified pair; utilizing said test instrument to calculate a predicted noise metallic based on said measured wideband noise-to-ground and a minimum expected pair balance; utilizing said test instrument to calculate and display a predicted signal-to-noise ratio based on said predicted signal level and said predicted noise metallic. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- the method comprising the steps of;
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14. A method of identifying the location of trouble on the shield of a distribution cable, the distribution cable having a first end proximate the DSLAM a second end opposite the first end, the cable including a shield having a ground connection, a plurality of pairs of conductors, each pair including a tip and a ring, the cable further including a plurality of access locations along the length of the cable for accessing the pairs of conductors;
- the method comprising the steps of;
identifying a reference pair of conductors; shorting and grounding first ends of said tip and ring of said reference pair; providing a test instrument having a plurality of leads and a memory for the storage of data; at first access location, electrically connecting said test instrument to said cable to be tested by electrically connecting a first lead of said test instrument to said tip, electrically connecting a second lead of said test instrument to said ring, and electrically connecting a third lead of said test instrument to the shield of said cable; measuring the loop resistance of the pair and storing said measured loop resistance in said memory of said test instrument; measuring the wideband noise to ground at the access location and storing said wideband noise to ground measurement in said memory of said test instrument; disconnecting said test instrument from the first location and re-connecting said test instrument at a subsequent access location; repeating said steps of measuring and storing said loop resistance, and measuring and storing the wideband noise to ground data at the access location; displaying the stored data associated with each access location such that the data is arranged based upon the measured loop resistance; analyzing said displayed data to determine if a large rate of change is provided between access locations; and identifying the access locations associated with the large rate of change as access locations of interest to isolate the predicted location of the shield problem between said access locations of interest. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
- the method comprising the steps of;
Specification