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158 Chpater 6
Custom Arb Waveform Generator
Working with Modulation Types
2. Press Mode > Custom > Real Time I/Q Baseband > Modulation Type > Define User I/Q > More (1 of 2) > Delete All
Rows
> Confirm Delete All Rows.
This loads a default 4QAM I/Q modulation and clears the I/Q Values editor.
3. Enter the I and Q values listed in the following table:
a. Press
0.5 > Enter.
b. Press
1 > Enter.
c. Enter the remaining I and Q values.
As the I value updates, the highlight moves to the first Q entry (and provides a default value of
0) and an empty row of data appears below the first row. As the Q value updates, the highlight
moves to the next I value. As you press the numeric keys, the numbers display in the active entry
area. If you make a mistake, use the backspace key and retype.
Also note that 0.000000 appears as the first entry in the list of Distinct Values, and that
0.500000 and 1.000000 are listed as the distinct values.
4. Press
More (2 of 2) > Display I/Q Map.
An I/Q State Map is displayed from the current values in the I/Q Values table.
The I/Q State Map in this example has four symbols. The I/Q State Map uses the following four
unique values: 0.5, 1.0, −0.5, and −1.0 to create the four symbols. It is not the number of values
that defines how many symbols a map has, but how those values are combined.
5. Press
Return.
When the contents of an I/Q Values table have not been stored, I/Q Values (UNSTORED)
appears on the display.
6. Press
More (1 of 2) > Load/Store > Store To File.
If there is already a file name from the Catalog of IQ Files occupying the active entry
area, press the following keys:
Editing Keys > Clear Text
7. Enter a file name (for example, NEW4QAM) using the alpha keys and the numeric keypad.
8. Press
Enter. The user-defined I/Q State Map should now be stored in the Catalog of IQ Files
and can be recalled even after the signal generator has been turned off.
Symbol Data I Value Q Value
0 0000 0.500000 1.000000
1 0001 −0.500000 1.000000
2 0010 0.500000 −1.000000
3 0011 −0.500000 −1.000000