Using time-domain reflectometry to identify manufacturing information for a passive printed circuit board

摘要

A method uses time-domain reflectometry to measure a signal reflection delay in a conductive trace formed on a specific passive printed circuit board, and uses the measured signal reflection delay as an index into a table storing a predetermined association between signal reflection delay and passive printed circuit board manufacturing information, wherein the table includes a plurality of predetermined signal reflection delay values, and wherein each of the predetermined signal reflection delay values is associated with unique passive printed circuit board manufacturing information. During manufacturing of the passive printed circuit board, a hole is drilled through the passive printed circuit board so that the hole intersects with the conductive trace and divides the conductive trace into a proximal segment extending from the connector to the hole and a distal segment that is electrically isolated from the proximal segment by the hole.