:MEASure:PLEVel:LINearity:DEFinition

Command Syntax

:MEASure:PLEVel:LINearity:DEFinition {RLMA120 | RLMC94 | EYE}

Query Syntax

:MEASure:PLEVel:LINearity:DEFinition?

Query Response

 {RLMA120 | RLMC94 | EYE}

Description

Selects the type of linearity measurement:

RLMA120

RLM (Ratio Level Mismatch) (IEEE 802.3 Annex 120D). Shown in the Level results table as RLM (A_120D). The linearity is defined as a function of the mean signal level transmitted for each PAM4 symbol level. The following picture identifies the voltage levels used in the following equations. In the following equations, the term ES stands for the Effective Symbol Level.

To optimize this algorithm:

• Send :MEASure:AMPLitude:DEFine:LEVel AVERage to base the measurement on average levels.

RLMC94

RLM (Ratio Level Mismatch) (IEEE 802.3 Clause 94). Shown in the Level results table as RLM (CL_94).

If the four levels measurements are the following values:

• L3 = 14.6 mV
• L2 = 7.5 mV
• L1 = –8.0 mV
• L0 = –15.2 mV

then, the linearity will be 0.715 as given by:

To optimize this algorithm:

1. Send :MEASure:AMPLitude:DEFine:LEVel CIDigits to base the measurement on Consecutive Identical Digits.
2. Enter the longest number of identical digits possible with your waveform. The higher the number, the more accurate the results will be.

EYE

Eye Linearity (CEI 4.0). Shown in the Level results table as Eye Linearity. Eye linearity is the ratio of minimum eye amplitudes (in Volts) to maximum eye amplitudes (in Volts).

To optimize this algorithm,

1. Send :MEASure:JITTer:DEFine:LWIDth PERCent to base the measurements on percent.
2. Send :MEASure:JITTer:DEFine:LWIDth:PERCent to enter the Percent of UI of 5%. The level data is averaged over the center 5% of the UI.