:MEASure:EYE:VECP:OMA:METHod

Command Syntax

:MEASure:EYE:VECP:OMA:METHod {OMAXp | UDEFined}

Query Syntax

:MEASure:EYE:VECP:OMA:METHod?

Description

Sets the method that the Optical Modulation Amplitude (OMA) is determined during a VECP measurement (:MEAS:EYE:VECP command).

UDEFined

This is the recommended selection. With this selection, you first must perform an Oscilloscope mode OMA measurement (:MEASure:OSCilloscope:OMAmplitude command) and enter the resulting value. OMA is the difference between the optical power of an NRZ one pulse and the optical power of an NRZ zero pulse. When you make the measurement, use a pattern that contains consecutive runs of ones and zeros as called out in many standards. This pattern allows the one and zero levels to settle out to minimize the effect of level transitions.

OMAXp

This is the default setting. The OMA value is automatically derived during the VECP measurement using the OMA at Crossing measurement. Since a pattern of consecutive ones and zeros is not used during the OMA measurement (as is done when entering a user-defined OMA value), the resulting VECP measurement can be too optimistic.

The query form of the command returns OMAX or UDEF.