Patent ID: 6668235
Filing Date: 2003-12-23
Classification: G01R

Abstract:
A method of indicating which data signals contributed to a selected location within a composite eye diagram for a group of data signals, the method comprising the steps of:(a) determining, for each data signal in the group, and at a collection of digital (time, voltage) pairs of which the time portion of each pair is an offset relative to a transition in a reference signal, the relative rate at which that data signal visits each (time, voltage) pair; (b) for each data signal in the group, storing relative rate of visitation information determined in step (a) in a respective data structure indexed by the (time, voltage) pairs; (c) for each data signal in the group, combining the respective stored relative rate of visitation information according to a rule to produce a single collection of such visitation information representing a composite eye diagram; (d) displaying, relative to (time, voltage) coordinate axes associated with the determining in step (a), a composite eye diagram for the single collection of visitation information produced in step (c); (e) positioning within the display of step (d), and in response to operator actuation of a screen pointer mechanism, a cursor at a selected location within the collection of (time, voltage) pairs; (f) indexing the respective data structures of step (b) with the (time, voltage) coordinates of the selected location of step (e); (g) subsequent to step (f), examining the relative rate of visitation information at the location in the data structures indexed by step (f) to discover which, if any, data signals visited that selected location; and (h) displaying legends indicating which, if any, of the data signals were discovered in step (g) to have visited the selected location.