Locating system for a cable system having a backbone and branch cables defining multiple terminations,申请号US19990412440-传众专利搜索

Locating system for a cable system having a backbone and branch cables defining multiple terminations

申请公布号：US7009375(B1)

申请号：US19990412440

申请日期：1999.10.05

申请公布日期：2006.03.07

申请人：

NORSCAN INSTRUMENTS LTD.

发明人：VOKEY DAVID E.;SONTAG KENNETH N.;LOEWEN MYRON

分类号：G01R19/00

主分类号：G01R19/00

摘要：A constant current termination is provided for cable locating tones on communication and control cables that may be buried or placed in underground duct structures. The constant current termination limits the current on each branch of the cable to that required for cable location, thus ensuring that branches furthest from the tone source have adequate current for location purposes. The termination is the same for each branch, regardless of its position along the cable system. This eliminates the need to calibrate and recalibrate termination distances for a cable on installation and when branches are added. It also allows the location of damaged cables where the tone signal strength on a damaged branch is less than that for which the termination was designed.