Patent ID: 6861975

Claim:
For use with an electrical apparatus having a signal transport path along which a plurality of nodes are distributed, one of said nodes being coupled with a reference frequency signal source that is operative to generate a reference frequency signal that propagates along said signal transport path and is distributed thereby to others of said plurality of nodes, said signal transport path imparting a variable delay therethrough of said reference frequency signal employed by said apparatus to operate electrical devices at said nodes, as a result of temperature variations along said signal transport path, a method of providing a measure of delay through said signal transport path between said one of said nodes and a respective one of said others of said nodes, said method comprising the steps of: (a) at a selected location along said signal transport path that is farther away from said one of said nodes than said others of said nodes, injecting a chirp signal into said signal transport path so that said chirp signal propagates as an upstream chirp signal over said signal transport path and is reflected from said first node and propagates therefrom along said signal transport path as a downstream chirp signal; and (b) at said respective node, extracting and processing said upstream chirp signal and said downstream chirp signal to derive a measure of signal transport delay through said signal transport path between said one of said nodes and said respective node.