Patent ID: 6804633
Filing Date: 2004-10-12
Classification: G01R

Abstract:
A method of selecting the order for sampling signal values to create an eye diagram, the method comprising the steps of:(a) defining a sample space having a time axis whose values are relative to a transition in a reference signal and having a voltage axis; (b) selecting a time resolution &Dgr;t and a voltage resolution &Dgr;v; (c) defining an array E indexed by an ordered pair of indices (x, y), where x represents consecutive multiples of &Dgr;t and y represents consecutive multiples of &Dgr;v, and E(x, y)i is one of xy-many elements within E and corresponds to a location in the sample space; (d) defining an array L indexed by the ordered indexes (x, y), where L(x, y)i is one of xy-many elements within L and corresponds to a location in the sample space; (e) defining an array H indexed by the ordered indexes (x, y), where H(x, y)i is one of xy-many elements within H and corresponds to a location in the sample space; (f) storing in each element of E a symbol e representing that the corresponding location in the sample space is eligible to be measured; (g) storing in each element of L a symbol âˆ’l representing that the corresponding location in the sample space is not a likely candidate for measurement; (h) storing in each element of H a null symbol Ã¸ representing that the corresponding location in the sample space has not produced any hits; (i) subsequent to steps (a)-(h), storing at selected locations in L a symbol l representing that those corresponding locations in the sample space are to be measured, and storing at those same selected locations in E a symbol âˆ’e representing that each corresponding location is no longer eligible for measurement; (j) pseudo randomly selecting a location L(x, y)i in L that contains the symbol l, and if there is such a location proceeding with steps (k)-(n), otherwise proceeding to step (t); (k) storing the symbol âˆ’l in L(x, y)i; (l) measuring the signal at the location in the sample space corresponding to (x, y)i and producing a value h(x, y)i; (m) if the value h(x, y)i measured in step (l) corresponds to the null symbol Ã¸, repeating steps (j)-(l); otherwise (n) if the value h(x, y)i measured in step (l) does not correspond to the null symbol Ã¸, performing steps (o)-(r); (o) storing the value h(x, y)i measured in step (l) into the array H at location H(x, y)i; (p) identifying the nearest neighbor locations of the location (x, y)i; (q) storing into L the symbol l at nearest neighbor locations that were identified in step (p) and that hold the symbol e in the array E; (r) for each location of L stored into by step (q), storing the symbol âˆ’e into the array E at the corresponding location; then (s) repeating step (j); and (t) cease the sampling of signal values to create the eye diagram.