Cray Research, Inc.

John B Eder

Melvin C August

James N Kruchowski

Apparatus and method for determining the electrical length of a signal flow path, such as a twisted-pair conductor, to create conductors of the same electrical length are disclosed. The term electrical length refers to a certain physical distance for a length of conductor for which an electrical signal travels, or propagates along the conductor, in a specified amount of time. The apparatus preferably includes a Time Domain Reflectometer 25 (including pulse generator means 30 and electrical response display means 20) which is cooperatively connected to a first end of a conductor pair 51 under test. The conductor pair 51 is inserted through a ground plane 60 or other impedance changing device. Means to mark or cut 62 the conductor 51 are located within the ground plane 60 or as close as possible to the point at which the impedance is changed. Processing means 40 are utilized to adjust the conductor 51 length relative to the ground plane 60. In operation, the pulse generator means 30 sends a pulse along the conductor 51. The ground plane 60 reflects a portion of the pulse back to the electrical response display means 20 with the signal propagation delay per unit mechanical length being calculated thereby.

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Eau Claire, WI, United States of America

John B Eder