:MEASure:PAM:LEVel

NRZ Waveform?

Use these commands instead:

PAM Levels Commands

Command Syntax

:MEASure:PAM:LEVel

Query Syntax

:MEASure:PAM:LEVel?

Description

Measures all amplitude levels (for example, levels 0, 1, 2, 3 of a PAM4 signal). The signal must be displayed as a single-valued waveform. On NRZ signals, this measurement will measure the zero or one levels. Before sending this command, select the actual level to be measured using the :MEASure:PAM:LEVel:LEVel child command. To measure all the levels on a signal, you must send this command once for each level as there is no command for simultaneously measuring all levels. The query form of the command returns the measured value. Sources can be any displayed PAM or NRZ waveform from a channel, differential channel, color-grade memory, or function. For example, CHAN1_1, CGMemory1, or FUNCtion1.

The amplitude of the selected level is calculated by:

  1. Identify one of each of the longest "n" logic levels on a PAMn signal or two levels on an NRZ signal.
  2. Determine the longest of each of the four levels and measure the level at the center 12.5% (1/8) of individual symbols.
  3. Calculate the mean amplitude level over each identified interval.

Setting the Timespan

You must set Infiniium's timespan wide enough so that each logic level is visible on the screen. For a PAM4 signal this would be four levels (0, 1, 2, 3), and for an NRZ signal this would be two levels (0, 1) . Failure to set the timespan wide enough results in an error. Consider the following items when setting the timespan:

  • If multiple identical levels are displayed, the level that is present for the longest time will be selected for measurement. For example, if two logic levels are shown on the waveform, with one being 100 ps and the other being 150 ps, the 150 ps level is selected to be measured.
  • To be considered a measurable level, the level must include at least 50% of the leading and trailing edges.
Settings That Affect This Measurement
Command Equivalent Setting
in PAM-N Analysis Setup Dialog Box		 Description
:MEASure:PAM:AMPLitude:UNITs Amplitude Units Sets the amplitude units for measurement.

Example Command Sequence

:CHANnel1:SIGNal:TYPE PAM4  //  Specify signal type.
:SYSTem:AUToscale
:MEASure:PAM:LEVel:SOURce CHANnel1
:MEASure:PAM:LEVel:LEVel LEVel3  //  Select logic level to be measured.
:MEASure:PAM:LEVel
:MEASure:PAM:LEVel?  //  Return measured value.