Technical data

ZSUBstitut: Zero SUBstitution; used for defining PRBN patterns in which a block
of bits is replaced by a block of zeros. The length of the block is defined by “SENSe
[1]:PATTern:ZSUBstitut[:ZRUN][?]” on page 252.
MDENsity: Mark DENsity; used for defining a PRBN pattern in which the user can
set the mark density. The mark density is set with “SENSe[1]:BLOCk:BLENgth[?]”
on page 234.
UPATtern<n>: User PATtern; used to define the contents of a pattern store. For
the Serial BERT, <n> can be 1 - 12.
FILename: A parameter that allows the remote user to load a user pattern from
the instrument's disk drive. This is the preferred mechanism for loading user
patterns in the Serial BERT.
BRM: A parameter that puts the error detector into Bit Recovery Mode. In BRM,
the error detector does not expect any specific data. This mode can be used if the
incoming data is completely unknown. To set the initial sampling point, use “SENSe
[1]:EYE:ALIGN:AUTO[?] ” on page 240.
BRM cannot be set if the error detector is in Burst mode.
For measuring BER in BRM, the error detector uses an additional, invisible sampling
point. The relative BER that can be measured in BRM is not necessarily the exact
BER-the error counter results may differ from precise measurements. Only if the
signal in the middle of the eye is free of errors, the relative BER matches the exact
BER.
The error detector stays in BRM until a pattern is selected.
N O T E
Compared with usual operation using expected patterns, Bit Recovery Mode
imposes some restrictions, for example:
•
No error location capture possible
•
No burst synchronization possible
•
No Auto Synchronization possible
•
No Synchronization Now possible
For details please refer to the User Guide.
The query form returns the pattern's types in short form.
N O T E
If a user-defined pattern is selected and the [:SELECT]? query is used, the response
is UPAT. The particular value of <n> or the name of the file specified in the command
form is not returned.
To get the path of a user pattern file, use the UFILe:NAME? command.
SCPI Command Reference 5
Agilent J-BERT N4903B High-Performance Serial BERT 251