com

Measure channel operating margin

Since R2024a

Syntax

c = com(obj)

c = com(obj,time)

c = com(___,Name=Value)

Description

c = com(obj) measures the channel operating margin (COM) from the eye diagram object obj.

c = com(obj,time) measures the channel operating margin from the eye diagram object obj at the time specified by time.

c = com(___,Name=Value) measures the channel operating margin from the eye diagram using one or more name-value pair arguments in addition to the input argument in the previous syntax. Unspecified arguments take default values.

Input Arguments

obj — Eye diagram object

eyeDiagramSI object

Eye diagram object, specified as an eyeDiagramSI System object™. The eye diagram object is created as an accumulation of 2-D histograms from the eye diagram data.

time — Time when COM is calculated

scalar

Time at which the function calculates the channel operating margin, specified as a scalar.

Data Types: double

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: c = com(obj,Extrapolation=Dual-Dirac) uses Dual-Dirac extrapolation method to generate the eye contours for measuring COM.

SER — Symbol error rate to measure channel operating margin

0 (default) | scalar

Symbol error rate to measure channel operating margin, specified at 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.

Data Types: char

TimeUnit — Unit for time coordinates to measure channel operating margin

Seconds (default) | Samples | UI

Unit for the time coordinates to measure channel operating margin, specified as seconds, samples, or UI.

Data Types: char

Output Arguments

c — Channel operating margin

vector

Channel operating margin.

Channel operating margin is the minimum signal-to-noise ratio for any given eye in the diagram.

$$\text{COM}=20{\log }_{10}\left(\text{Min}\left(\frac{\text{Signal}}{\text{Noise}}\right)\right)$$

Signal-to-noise ratios are determined from eye amplitude (signal amplitude) and the difference between eye amplitude and eye height (noise amplitude).

Version History

Introduced in R2024a