Keysight EXG and MXG X-Series Signal Generators User’s Guide 309
Using Custom Digital Modulation for N5172B/82B with Option 431 and 653/655/656/657
Differential Encoding
Press Mode > ARB Custom Modulation > Single Carrier Setup > Quick Setup (desired format) >
Modulation Type > Select > More > Define User I/Q > More 1 of 2 > Load Default I/Q Map >
QAM > 4QAM.
This loads a default 4QAM I/Q modulation and displays it in the I/Q table editor.
The default 4QAM I/Q modulation contains data that represent 4 symbols (00, 01, 10, and 11)
mapped into the I/Q plane using 2 distinct values (1.000000 and −1.000000). These 4 symbols will
be traversed during the modulation process by the symbol table offset values associated with each
symbol of data. Refer to Figure 9-41.
Figure 9-41
Accessing the Differential State Map Table Editor
Press Configure Differential Encoding.
This opens the Differential State Map table editor, as shown. At this point, you see the data
for the 1st symbol (00000000) and the cursor prepared to accept an offset value.You are now
prepared to create a custom differential encoding for the user–defined default 4QAM I/Q
modulation. Refer to Figure 9-42 on page 309.
Figure 9-42
Editing the Differential State Map
1. Press 1 > Enter.
Data
Symbol Table Offset Values Entry Area
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