# Peak-Peak at Hit Ratio

The Peak-Peak at Hit Ratio measurement can be performed on both NRZ and PAM waveforms. Two annotation labels are placed on the waveform. Infiniium positions one label at the peak maximum power at the specified hit ratio and the other label at the peak minimum power at the specified hit ratio of the waveform.

Pmax is based on a 1e-2 hit ratio, where Pmax and Pmin are 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.

The hit ratio's default setting is 1e-2 and is based on the IEEE 802.3cu standard. However, after selecting the measurement you can change this ratio if needed.

## To measure

1. Click the toolbar's Amplitude tab.
2. Click the More buttons to locate the Peak-Peak at Hit Ratio button.
3. Click the button.
4. When the Settings dialog is displayed, change the default Hit Ratio, if desired. If the measurement is being performed on an optical channel, the dialog allows you to select either Watts or dBm as the measurement units.
5. Select the Region in which to make the measurement:
   - Displayed Waveform — is what you see in the waveform window (which can be a zoomed-in view of the complete waveform).
   - Entire Waveform — specifies the complete waveform.
   - Region N — If regions are enabled for the selected signal, you can select one of those regions.

## SCPI Command

`:MEASure:VERTical:PPHRatio`