About the Channel Symbol Table (1xEV-DO) (Reverse Direction Only)
When 1xEV-DO Demodulation is enabled, selecting Chan Syms/Errs trace data shows the symbol table and error summary trace data for the specified Walsh code number and Walsh code length. The bottom section of the display shows the symbol table data and the upper section shows the error summary data. This topic discusses the code channel Symbol Table trace data. The Error Summary trace data is discussed under About the Channel Error Summary.
These data results are only apply to Reverse link direction signals.
The Chan Symbol table shows the binary bits for each measured symbol in the specified Walsh code number and Walsh code length. These parameters are specified in the Despread Channel Walsh-Code Number and Walsh Code Length drop down lists, located in the 1xEV-DO Demod Properties dialog box ( tab).
The first bit in the table corresponds to the first bit of the first symbol. To make the table easier to read, the VSA shows a fixed number of bits (eight), followed by a space.
For Reverse link signals, the "I" and "Q" data channels are logically separate signals. All trace data contains both the "I" and the "Q" channels of the signal, except the symbol table data. The symbol table shows either the "I" channel symbol bits or the "Q" channel symbol bits. The "I" and "Q" channel data is specified by the "IQ" Branch parameters in the Demod Properties Channel/Layer tab ( tab).
In addition, the VSA shows numbers to the left of each row. These numbers indicate the bit position of the first bit in the row. For example, if 192 is displayed by the third row, the first bit in the row is the 192nd bit in the digital data stream.
Here's an easy way to show the bits that correspond to a point in the channel constellation diagram:
Display the constellation diagram in one grid, the symbol table in another and then turn on the and the feature. When you place the marker on a point in the constellation diagram, the VSA highlights the corresponding bits in the symbol table.
Use the arrow keys on the keyboard or the mouse wheel to move the marker from one symbol to the next. Or you can use the marker X Position to move to any specified symbol location.
Error Summary Data Information
See About the Channel Error Summary Data.
See Also
