Amplitude at Lower
The Oscilloscope mode Amplitude at Lower is the measure of the amplitude value of the lower threshold. This measurement may be compatible with PAM4 signals, depending on the PAM4 waveform. The measurement can be restricted to a measurement region. An annotation is placed on the display at the measured value. By default, this is the standard IEEE 10% threshold measurement level definition. The lower threshold value can be set to 10%, 20%, or a custom value. The Waveform Base and Waveform Top are first located and these values are used to determine the threshold value.
PAM4 Compatibility. Because this measurement is based on waveform top and base levels and the passing of the waveform's edge through proximal, mesial, and distal thresholds, the measurement is not designed for PAM4 signals. However, the measurement may be able to be made on PAM4 signals if the waveform top and base definitions are manual set. This can be attempted using the Top-Base Definition tab of the Configure Measurements dialog.
This measurement may be compatible with PAM4 signals, depending on the PAM4 waveform. PAM measurement capability requires the Research and Developement or Manufacturing package license or the legacy PAM-N Analysis license.
The entire display or measurement 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 (click Measure > Configure Base Measurements):
- Thresholds tab
- Top-Base Definition tab
To measure
- Select Oscilloscope Mode.
- Click the toolbar's Amplitude tab.
- Click the toolbar's More buttons to locate the Amplitude at Lower button.
- Click the button.
- If measurement regions are enabled, the Select Measurement Region, Setting dialog is displayed. Select the area over which the measurement is to be performed: a Region or the Entire Display.
SCPI Command
:MEASure:OSCilloscope:VLOWer