# PAM Tx Power Excursion

The Transmitter Power excursion (TPE) measurement for PAM4 signals is IEEE 802.3cu compatible and is given by the following equation:

where:

**P**is based on a 1e-2_{max}*hit ratio*, where P_{max}is the smallest power level that results in the number of samples above that level not exceeding the product of hit ratio and total number of observed samples. All samples are acquired in a single unit interval eye diagram.**P**is based on a 1e-2_{min}*hit ratio*, where P_{min}is the largest power level that results in the number of samples below that level not exceeding the product of hit ratio and total number of observed samples. All samples are acquired in a single unit interval eye diagram.- P
_{avg}is the average power of the signal.

When the measurement is selected, the **Select Measurement Settings** dialog opens where you can specify **Hit Ratio** and **Units** (Watts or dBm). By default, the **Hit Ratio** is set to1.0E-2.

This measurement is not affected by the settings in the**PAM-N Analysis Setup** dialog.

This measurement can also be performed on an NRZ signal.

## To measure

- Select Eye/Mask Mode.
- Click
**Auto Scale**in the menu toolbar. - Click the toolbar's
**PAM**tab. - On the toolbar, locate and click the
**Tx Power Excursion**button.

## SCPI Command

`:MEASure:EYE:PAM:TPEXcursion`