# Crossing Percentage

The Crossing Percentage is a measure of the amplitude of the crossing points relative to the one level and zero level. Five annotation labels are placed on the eye diagram: one label at the eye crossing point and the remaining two sets of level labels at the mean value of the one level and the mean value of the zero level. The one and zero level measurements are made in a section of the eye referred to as the eye window boundaries. The default value for the NRZ eye window is the central 20% of the symbol period.

A vertically thin measurement window is placed horizontally through the crossing points, and a horizontal histogram is used to determine the mean location (in time) of the crossing point.

A narrow vertical histogram is used to determine the amplitude of the crossing points.

The mean derived from the horizontal and vertical histogram results in the amplitude of the crossing point . Crossing percentage is then determined by the following:

This measurement applies to NRZ waveforms and not to PAM waveforms.

## Configurable Measurement Parameters

This measurement is affected by the following setting (choose Measure > Thresholds...):

- Eye tab

## To measure

1. Click the measurement toolbar's Eye Meas tab.
2. Click Auto Scale in the menu bar.
3. Click the More buttons to locate the Crossing % button.
4. Click the button.

## SCPI Command

`:MEASure:EYE:CROSsing`