eyeContour

Contour of eye opening from eye diagram

Since R2024a

Description

Use the eye contour object to store data related to a set of contours at the specified symbol error rate (SER). The eye contours are generated from an eye diagram.

Creation

Syntax

c = eyeContour(eyeObj)

c = eyeContour(eyeObj,Name=Value)

Description

c = eyeContour(eyeObj) creates an eye contour object from the eye diagram object eyeObj using default values.

c = eyeContour(eyeObj,Name=Value) sets the Properties (Mixed-Signal Blockset) of the eye contour object to the specified values.

For example, c = eyeContour(eyeObj,SER=1e-3,Extrapolation='None') creates an eye contour object from the eye diagram object eyeObj at the symbol error rate 1e-3.

Input Arguments

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`eyeObj` — Eye diagram object
eye diagram object

Eye diagram object used to create the eye contour object. The eye diagram object is created as an accumulation of 2-D histograms from the eye diagram data.

Properties

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`Contour` — Numeric contour data for each eye opening
`[]` (default) | 3-D array

Numeric contour data consisting of upper and lower contours for each eye opening, specified as a 3-D array. Contours are row vectors with one element for each of the TimeBins properties from the original eyeDiagramSI object. The object indexes the contours from the lowest eye center amplitude to the highest.

By default, the property is automatically set from the value defined in the eyeObj eye diagram object.

Example

Contour(1, :, 3) represents the lower contour of the third eye.

Contour(2, :, 1) represents the upper contour of the first eye.

Data Types: double

`OuterContour` — Numeric contour data of outer contours
`[]` (default) | vector

Numeric contour data consisting of two outer (below and above) contours for the whole eye diagram, specified as a vector.

OuterContour(1, :) represents the lower limit of the eye. Contour(2, :) represents the upper limit of the eye.

By default, the property is automatically set from the value defined in the eyeObj eye diagram object.

Data Types: double

`SER` — Symbol error rate to generate contour
`0` | scalar

Symbol error rate to generate contours, specified as a scalar.

Data Types: double

`Extrapolation` — Extrapolation method to generate contour
`None` (default) | `Dual-Dirac`

Extrapolation method to generate contours, specified as None or Dual-Dirac. For more information, see Extrapolation (Mixed-Signal Blockset).

Data Types: char

`SampleInterval` — Time between adjacent samples in input data
`1` (default) | scalar

Elapsed time between adjacent samples in the input data, specified as a scalar in seconds.

By default, the property is automatically set from the value defined in the eyeObj eye diagram object.

Data Types: double

`SymbolTime` — Time span of one symbol
`8` (default) | scalar

Time span of one symbol, specified as a scalar in seconds.

By default, the property is automatically set from the value defined in the eyeObj eye diagram object.

Data Types: double

`SymbolThresholds` — Nominal center amplitude for eye opening
vector

Nominal center amplitude for each eye opening in the eye diagram, specified as a vector.

By default, the property is automatically set from the value defined in the eyeObj eye diagram object.

Data Types: double

Object Functions

`eyeHeight` (Mixed-Signal Blockset)	Measure vertical eye opening
`eyeWidth` (Mixed-Signal Blockset)	Measure horizontal eye opening
`eyeArea` (Mixed-Signal Blockset)	Measure eye area
`upperContour` (Mixed-Signal Blockset)	Measure upper contour of eye diagram
`lowerContour` (Mixed-Signal Blockset)	Measure lower contour of eye diagram
`closedContour` (Mixed-Signal Blockset)	Measure closed contour of eye diagram

More About

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Extrapolation

Extrapolation method is used to constitute the relation between specific SER values and the shape of the 2-D histogram. It is the core technology behind the generation of bathtub plots and eye contours.

During extrapolation method, the data is pre-processed, usually one symbol at a time on only a 1D slice of the said symbol.

The None extrapolation method is a previous neighbor interpolation of the cumulative sum an eye slice. For horizontal eye slices, the extrapolation uses the timing origins. For vertical eye slices, the extrapolation uses the symbol thresholds.

When moving outward from the center of the eye, it is a previous neighbor interpolation. When moving across the eye from one side to the other, it appears as a next neighbor interpolation that switches to a previous neighbor interpolation as you pass the center of the eye. This way, the result for a symbol error rate is a conservative estimate from the perspective of the eye opening, based on the data.

The Dual-Dirac extrapolation algorithm first fits the Dual-Dirac PDF to a column of the split histogram. Then it uses those coefficients to calculate the inverse Dual-Dirac CDF for the specified SER(s). It is only applicable to systems with an exponential impulse response whose time constant is on the order of the time for one symbol, or less. The algorithm is also significantly slower that the None extrapolation method.

Version History

Introduced in R2024a

eyeContour

Description

Creation

Syntax

Description

Input Arguments

eyeObj — Eye diagram object eye diagram object

Properties

Contour — Numeric contour data for each eye opening [] (default) | 3-D array

Example

OuterContour — Numeric contour data of outer contours [] (default) | vector

SER — Symbol error rate to generate contour 0 | scalar

Extrapolation — Extrapolation method to generate contour None (default) | Dual-Dirac

SampleInterval — Time between adjacent samples in input data 1 (default) | scalar

SymbolTime — Time span of one symbol 8 (default) | scalar

SymbolThresholds — Nominal center amplitude for eye opening vector

Object Functions

More About

Extrapolation

Version History

See Also

`eyeObj` — Eye diagram object
eye diagram object

`Contour` — Numeric contour data for each eye opening
`[]` (default) | 3-D array

`OuterContour` — Numeric contour data of outer contours
`[]` (default) | vector

`SER` — Symbol error rate to generate contour
`0` | scalar

`Extrapolation` — Extrapolation method to generate contour
`None` (default) | `Dual-Dirac`

`SampleInterval` — Time between adjacent samples in input data
`1` (default) | scalar

`SymbolTime` — Time span of one symbol
`8` (default) | scalar

`SymbolThresholds` — Nominal center amplitude for eye opening
vector