Agilent Technologies E8257D, User Manual

Page: 188 / 318

174 Chapter 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