Technical data

To query the status of the Error Location Capture measurement:
• Use the following commands:
– IVI-COM: IAgilentN490xEDErrorLocation.ReadState
– SCPI: SENSe1:ELOCation:VERBose?
• In the Operation Status register, check the Error Location Capture bit (bit 14) :
– If the bit is high, the measurement is running.
– If the bit is low, the measurement is not running. It may be not started yet,
successfully finished, or aborted.
Handling the Results
Once an Error Location Capture has been successfully finished, you can get the
following results:
• Location of first errored bit
• Number of all errored bits in the stored bit sequence
• Comparison pattern between expected pattern and received data
A bit sequence neighbouring the errored bit is written to a file. The captured
data is saved as an alternating pattern:
– Pattern A contains the expected data.
This is the pattern downloaded to the error detector.
– Pattern B contains the errored data:
This is a bit sequence where 1s mark the bit positions where an error
occurred and 0s mark the positions where the expected bits were received.
The captured pattern is the bit stream detected at the analyzers data input. To
calculate the captured pattern, XOR the bits from pattern A with the bits from
pattern B.
The pattern description contains the first error, the error count, date and time.
The name of the pattern file is ELOC_RESULT_CURRENT.ptrn for the current
capture and ELOC_RESULT_PREVIOUS.ptrn for the previous capture. These
patterns are saved under C:\<Instrument Model>\Pattern on the instrument.
T I P
The position of the first errored bit is automatically taken over as the bit position
for BER location mode.
Recommended Programming Techniques 3
Agilent J-BERT N4903B High-Performance Serial BERT 45
Measurement Status