Richard A Nygaard

US Patent:

20030083833, May 1, 2003

Filed:

Oct 29, 2001

Appl. No.:

10/020673

Inventors:

Richard Nygaard - Colorado Springs CO, US

International Classification:

G06F019/00

US Classification:

702/067000

Abstract:

An eye diagram analyzer equips each SUT data and clock signal input channel with individually variable delays in their respective paths. For a range of signal delay of n-many SUT clock cycles, the SUT clock signal delay might be set at about n/2. For each data channel there is specified a point in time relative to an instance of the delayed clock signal (data signal delay) and a voltage threshold. The specified combination (data signal delay, threshold and which channel) is a location on an eye diagram, although the trace may or may not ever go through that location. A counter counts the number of SUT clock cycles used as instances of the reference for the eye diagram, and another counter counts the number of times the specified combination of conditions was met (“hits”). After watching a specified combination for the requisite length of time or number of events, the number of SUT clock cycles involved and the associated number of hits are stored in memory using a data structure indexed by the components of the specified combination (data signal delay, threshold). Next, a new combination of data signal delay and threshold is specified and a measurement taken and recorded in the data structure. The process is repeated until all possible combinations within a stated range of data signal delay and threshold voltage (using specified resolution/step sizes for delay and voltage) have been investigated. As this process proceeds under the control of firmware within the logic analyzer, other firmware can be examining the data structure and generating a partial eye diagram visible on a display, and that will be complete soon after the measurement itself is finished.

US Patent:

20030158687, Aug 21, 2003

Filed:

Jan 31, 2002

Appl. No.:

10/061918

Inventors:

Richard Nygaard - Colorado Springs CO, US
Jeffrey Haeffele - Monument CO, US

International Classification:

G06F019/00

US Classification:

702/117000

Abstract:

An eye diagram analyzer assigns a plurality of SUT data signals to be members of a labeled group of channels. There may be a plurality of such groups. In addition to mere superposition in an (X, Y) display space of the various i-many (X, Y)-valued pixels for individual component eye diagrams associated with that group, other measured data for those pixels within a group can be merged in various different modes to produce corresponding composite eye diagram presentations. E.g., in a Normalized Signal Density Mode the number of hits at each trial measurement point is summed over all channels in the group, and then divided by the total number of clock cycles measured for the imeasurement point in that group to produce a density Dassociated with the corresponding ipixel: (X, Y, D). If Dis rendered as a color or an intensity, the resulting eye diagram includes a representation (the D) of a normalized density of transitions at each point (X, Y), relative to that group as a whole. As a further example, in a Channel Density Mode, each Dis produced by accumulating, for each of N-many channels, a 1/N for each sample (value of i) with non-zero signal activity, and dividing the accumulation by N. If that collection of Dis rendered as a color or an intensity, the resulting composite eye diagram includes a representation (the D) at each (X, Y) point of the degree of coincidence among, or a degree of similarity between, the channels in the group.

US Patent:

20030187620, Oct 2, 2003

Filed:

Mar 28, 2002

Appl. No.:

10/109282

Inventors:

Richard Nygaard - Colorado Springs CO, US
Jeffrey Haeffele - Monument CO, US

International Classification:

G06F019/00

US Classification:

702/189000

Abstract:

An eye diagram analyzer can assign a plurality of SUT data signals to be members of a labeled group of channels. There may be a plurality of such groups. The measured data for components within a group can be merged according to various different modes into a composite eye diagram presentation. When a composite eye diagram is being displayed, the operator may position a screen pointer (cursor) over some interesting part of the eye diagram, and the analyzer will display a list those channels that contributed to the displayed pixels in that part of the eye diagram, as well as other related information. The operator may also select a channel from among the group, and then have the displayed pixels for which it is responsible be displayed in a selected color or otherwise highlighted in a way that allows them to be distinguished from all others.

US Patent:

20030193525, Oct 16, 2003

Filed:

Apr 11, 2002

Appl. No.:

10/120565

Inventors:

Richard Nygaard - Colorado Springs CO, US

International Classification:

G09G005/00

US Classification:

345/810000, 345/835000

Abstract:

An eye diagram analyzer can assign a plurality of SUT data signals to be members of a labeled group of channels merged into a composite eye diagram presentation. When a composite eye diagram is being displayed, the operator may select a channel from among the group, and then have the pixels associated with that channel be displayed in an altered manner (highlighted) that allows them to be distinguished from all others, to determine if the behavior of that channel contributes to a condition in the eye diagram that is of interest. The menu from which channels may be selected includes at least one button in a fixed location, and which when clicked on, automatically selects the next item in the list within that menu. In this way the mouse can be positioned just once, and then clicked as often as needed without further motion, allowing the operator to continuously observe, without re-direction of his visual attention, what effect, if any, is produced in the composite eye diagram. There may be one button for traversing the menu list in each direction. Traversing (automatic selection of an adjacent entry in the list) might be one step per click, or if the click is extended, be automatically repeated at some convenient rate. When one end of the list is reached the next selected item can be the item at the other end of the list.

US Patent:

20030202427, Oct 30, 2003

Filed:

Apr 25, 2002

Appl. No.:

10/132609

Inventors:

Richard Nygaard - Colorado Springs CO, US
David Eskeldson - Colorado Springs CO, US

International Classification:

G04B047/00

US Classification:

368/010000

Abstract:

Delay induced apparent amplitude desensitization in a data signal channel and its accompanying worm-like distortion in an Eye Diagram Analyzer is avoided by altering the measurement to avoid the need for any substantial delay in the path of the data channel threshold comparison signals. In a first technique, only enough delay will be inserted in the data channels to produce the relative adjustments needed to compensate for skew between the data channels, as determined by a calibration operation, and it is these de-skewed, but otherwise un-delayed, data threshold comparison signals that are, in rapid succession, clocked into the latches whose difference registers a hit at a given (time, voltage) pair. The clock path delay is then varied from a minimal value to a sufficiently large value capable of spanning a desired the number of eye diagram cycles. In a second technique, the needed amounts of de-skew delay found by the calibration operation are noted, and then the actual delays in the data path are set back to zero. The clock path delay is swept as in the first technique. The de-skewing operation is then performed in post-processing that produces the eye diagram after the measurement is complete. In either technique, the short width of transitions in the data threshold comparison signals that are associated with threshold values near the extremes of data signal excursion are no longer swallowed by the finite bandwidth of a long delay line, since the delay lines in the data channel paths now either introduce only just enough delay to compensate for skew (and those amounts are very short), or, do not introduce any extra delay at all.

US Patent:

20040024547, Feb 5, 2004

Filed:

Jul 31, 2002

Appl. No.:

10/210025

Inventors:

Richard Nygaard - Colorado Springs CO, US

International Classification:

G01R013/02
G06F019/00
G01R025/00
G01R029/02

US Classification:

702/067000

Abstract:

Once an eye diagram measurement is begun and there is an eye diagram displayed, different on-screen measurement tools may be used singly, or in combination. Each measurement involves indicating with cursors and line segments regions of the eye diagram that are of interest, and a parameter or parameters associated with each measurement tool in use is reported in a (usually) separate area of the display. An Eye Limits measurement allows the specification of a point within an eye diagram, whereupon it finds and reports the eye diagram coordinates first encountered along horizontal and vertical lines extended from the selected point (i.e., “eye opening” size). The coordinates of the point itself are also reported. A Four Point Box measurement allows the construction on the eye diagram of a rectangle having sides parallel to the coordinate axes of the eye diagram. The coordinates of the rectangle are reported, as well as information about the number of points on the eye diagram that occur on or within the rectangle. A Six Point Box and a Diamond may be defined and used in a like fashion. A Slope Tool uses two end points to define an intervening line segment, whose slope and location can be adjusted to match some region of interest on the eye diagram. The pertinent information about the line segment and its end points is then reported. A Histogram measurement may be performed on any selected slice of the eye diagram. The histogram is thus of a distribution of number of hits versus either time axis location at a fixed voltage, or voltage at a fixed time location. Duplicate cursors appear on both the line defining the slice and within the histogram. Either cursor can be grabbed and moved, which then also moves the other. The scale for the number of hits for either histogram may be either linear or logarithmic.

US Patent:

20040153266, Aug 5, 2004

Filed:

Jan 31, 2003

Appl. No.:

10/355308

Inventors:

Richard Nygaard - Colorado Springs CO, US

International Classification:

G01R013/02

US Classification:

702/068000

Abstract:

The time needed to perform an eye diagram measurement is minimized by initially randomly investigating the (X, Y)that lie on a “starting” line crossing the sample space and expected to intersect any eye diagram. This finds a location on the eye diagram. Then the eye diagram is traversed as it is discovered by investigating nearest neighbors of locations found to belong to the eye diagram. Two arrays E and L of bits are established. The bits of E represent “eligible” (X, Y), while those of L represent “likely” (X, Y). At the very start of the measurement all bits in the eligible array E are set and all those in the likely array L are cleared, except that the starting line is established by setting in L and clearing in E locations for the corresponding (X, Y). Thereafter, locations in L that have Is are measured in a randomly selected order. The presence or absence of activity is duly recorded by the conventional data collection mechanism for use in the resulting eye diagram, and the measured location is then deleted from L by setting the corresponding bit to 0. However, if there was some activity, the nearest neighbors for that (X, Y)are promoted from E to L. Promotion means that the corresponding bits are cleared in E and set in L. When no further set bits remain in L, promote from E to L any remaining locations in E on the horizontal rows corresponding the maximum and minimum voltages thus far discovered for the signal. After that the measurement can stop when no further set bit remain in L, or, if desired, any remaining (i.e., unmeasured) locations identified by E can subsequently be measured by promoting them to L.

US Patent:

20040225460, Nov 11, 2004

Filed:

Apr 15, 2004

Appl. No.:

10/824680

Inventors:

Richard Nygaard - Colorado Springs CO, US

International Classification:

G01R013/02

US Classification:

702/067000

Abstract:

An eye diagram analyzer equips each SUT data and clock signal input channel with individually variable delays in their respective paths. For a range of signal delay of n-many SUT clock cycles, the SUT clock signal delay might be set at about n/2. For each data channel there is specified a point in time relative to an instance of the delayed clock signal (data signal delay) and a voltage threshold. The specified combination (data signal delay, threshold and which channel) is a location on an eye diagram, although the trace may or may not ever go through that location. A counter counts the number of SUT clock cycles used as instances of the reference for the eye diagram, and another counter counts the number of times the specified combination of conditions was met (“hits”). After watching a specified combination for the requisite length of time or number of events, the number of SUT clock cycles involved and the associated number of hits are stored in memory using a data structure indexed by the components of the specified combination (data signal delay, threshold). Next, a new combination of data signal delay and threshold is specified and a measurement taken and recorded in the data structure. The process is repeated until all possible combinations within a stated range of data signal delay and threshold voltage (using specified resolution/step sizes for delay and voltage) have been investigated. As this process proceeds under the control of firmware within the logic analyzer, other firmware can be examining the data structure and generating a partial eye diagram visible on a display, and that will be complete soon after the measurement itself is finished.