# Amplitude at Middle

Amplitude at Middle is the measure of the amplitude value of the middle threshold. This measurement may be compatible with PAM signals, depending on the PAM waveform. The measurement can be restricted to a region. An annotation is placed on the display at the measured value. By default, this is the standard IEEE 50% threshold measurement level definition. The middle threshold value can be set to 50% or a custom value. The Waveform Base and Waveform Top are first located and these values are used to determine the threshold value.

PAM Compatibility. Because this measurement is based on waveform top and base levels and the passing of the waveform's edge through lower, middle, and upper thresholds, the measurement is not designed for PAM signals. However, the measurement may be able to be made on PAM signals if the waveform top and base definitions are manually set. This can be attempted using the Thresholds tab of the Configure Measurements dialog box.

This measurement may be compatible with PAM signals, depending on the PAM waveform.

The display, waveform, or region is used to calculate the result. Therefore, position a single cycle or an integer number of falling edges in the display or region.

## Configurable Measurement Parameters

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

- Thresholds tab

## To measure

1. Click the toolbar's Amplitude tab.
2. Click the toolbar's More buttons to locate the Amplitude at Middle button.
3. Click the button.
4. 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:VMIDdle`