Protocol analysis
R&S
®
RTE
779User Manual 1326.1032.02 ─ 20
If no user-defined frame description should be suitable to identify an incoming frame,
per default such a "missed" frame is reproduced as "Undescribed Bits" in the honey-
comb display, as in the example in Figure 13-86. These bits are not shown in the
results table.
Note: There may be frame descriptions that positively identifies each kind of frame,
e.g. if no equal operator (see Condition) is defined for any of the cells. This "catches"
every frame, even if there are other frame descriptions to follow in the frame list.
Therefore, if a "catch all" frame description is used, it should be placed at the end of
the frame list, or it overwrites any subsequent frame description. However, instead of
using a "catch all" frame description, the built-in "undescribed bits" display as men-
tioned above may be the better approach to create frame descriptions.
It is in the responsibility of the user to define unambiguous settings for each frame
type. For a description of these conditions in XML file format and the required XML
grammar and syntax, see Chapter 13.14.2.3, "XML syntax", on page 785.
Remote command:
BUS<m>:CMSB:FRAMe<n>:TYPE on page 1743
BUS<m>:CMSB:ADDFrame on page 1743
BUS<m>:CMSB:CLR on page 1743
BUS<m>:CMSB:FCOunt? on page 1743
Cells
A cell description (which is represented by one row in one frame description) can be
created at any position of a frame description (see Frames) by clicking on "Insert". This
brings up a new cell description in the active frame description, on top of the selected
position. The "Append" button adds a cell description at the end of a frame description,
below the lowest existing cell description. The number of cell descriptions is not limited.
The "Remove" button deletes a selected cell description from the active frame descrip-
tion.
The cell result can be selected to be displayed in a specified result column of the
decode table (see "Result Column" on page 784).
Note: The cell descriptions must be sequential and complete. No gaps are allowed,
since the Bit Count is used to calculate the start position of the next cell.
A frame type is identified when all user-defined cell conditions are met, which can be
regarded as related by the Boolean AND operator.
This can also locate a synchronization pattern, specified by the equal operator in the
Condition cell. For example, if you define a "Preamble" cell with the condition
=FFFFFFFF, the decoder scans the data for this pattern, and then synchronize to it.
The cells in a frame are described by:
●
Cell Name
●
Bit Count
●
Condition
●
Numeric Format
●
Bit Order
●
Color
●
Result Column
Custom: Manchester / NRZ (option R&S
RTE-K50)M
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