Agilent Technologies E8247C PSG CW - Manual (Page 150)

140 Chapter 6
Custom Arb Waveform Generator
Working with Modulation Types
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 E8267C PSG signal generator has been turned off.
Modifying a Predefined I/Q Modulation Type (I/Q Symbols) & Simulating Magnitude Errors & Phase Errors
Use the following procedure to manipulate symbol locations which simulate magnitude and phase errors. In
this example, you edit a 4QAM constellation to move one symbol closer to the origin.
1. Press
Preset
.
2. Press
Mode
>
Custom
>
Real Time I/Q Baseband
>
Modulation Type
>
Define User I/Q
>
More (1 of 2)
>
Load Default I/Q Map
>
QAM
>
4QAM
.
This loads a default 4QAM I/Q modulation into the I/Q Values editor.
3. Press
More (2 of 2)
.
4. In the I/Q Values editor, navigate to Data 00000000 and press
Edit Item
.
5. Press
.235702
>
Enter
, then
.235702
>
Enter
.
When you press
Enter
the first time, the I value updates and the highlight moves to the first Q entry. The
second time, the Q value updates and the highlight moves to the following I entry.
6. Press
Display I/Q Map
. Note that one symbol has moved, as shown.