UTP cable length measuring instrument feturing TI´s interface circuits

Time Domain Reflectometry (TDR) diagnostic features of Ethernet physical transceiver chips are explored for evaluating their applicability for construction of an UTP-cable length-measurement and diagnostic instrument. The instrument is mainly intended as an aid during installation and for post-installation documentation. Dithering method is applied for length measurement to increase the resolution, based on physical patch-cable switchover and/or discrete component cable emulation and/or programmable delay-line delay-dithering. A practical experiment with length dithering using cable patches confirms the feasibility of the idea.