Technical data

The Operation Status register should catch negative transitions on the ERR LOC

CAPTURE bit (bit 14).

Check the status registers to see if Error Location Capture has stopped.

If it has stopped, check the status of Error Location Capture. It could have either

been aborted or successful.

See also “Handling the Results” on page 45 for more information.

How to Abort Error Location Capture

Error Location Capture runs until it detects an error and stops. If there are no errors

in the data stream, it would run forever. It can also be interrupted by a remote

program (or user) by the following actions:

• Disabling error location

– IVI-COM:

IAgilentN490xEDErrorLocation.Mode =

AgilentN490xEDErrorLocationModeOff

– SCPI:

SENS:ELOC OFF

• Incorrect sample point (faulty measurement)

• Action not compatible with error location currently being performed, for

example:

– Selecting a new pattern

– Changing the current pattern

– Starting synchronization or alignment

There are various other actions that also abort the run. Changing the sampling

point has no effect (as long as the sampling point does not leave the eye).

Understanding the Status

Error Location Capture is not immediately able to detect bit errors when the start

command is given, and does not immediately terminate when the stop command

is given. There is a specific delay that must be heeded. For remote programming,

it is sufficient to wait 400ms.

You can check both, the status of the command and the status of the measurement.

To query the status of the Error Location Capture command:

• IVI-COM:

IAgilentN490xEDErrorLocation.CaptureErrors

• SCPI:

SENSe1:ELOCation?

3 Recommended Programming Techniques

44 Agilent J-BERT N4903B High-Performance Serial BERT

Command Status