Using Differential Encoding - Keysight E8267D User Manual

Custom Real Time I/Q Baseband
Working with Differential Data Encoding
When applied to the user–defined default 4QAM I/Q map, starting from the 1st
symbol (data 00), the differential encoding transitions for the data stream (in
2–bit symbols) 0011100001 appear in the previous illustration.
As you can see, the 1st and 4th symbols, having the same data value (00),
produce the same state transition (forward 1 state). In differential encoding,
symbol values do not define location; they define the direction and distance of
a transition through the I/Q State Map.
For instructions on configuring differential encoding, see
Differential Encoding" on page

Using Differential Encoding

Differential encoding is a digital–encoding technique that denotes a binary
value by a signal change rather than a particular signal state. It is available for
Custom Real Time I/Q Baseband mode. It is not available for waveforms
generated by Arb Waveform Generator mode.
The signal generator's Differential State Map editor enables you to
modify the differential state map associated with user–defined I/Q and
user–defined FSK modulations. In this procedure, you create a user–defined
I/Q modulation and then configure, activate, and apply differential encoding to
the user–defined modulation. For more information, see
Differential Encoding" on page
This section includes information on following:
— Configuring User–Defined I/Q Modulation
—
—
Configuring User–Defined I/Q Modulation
1. Press Preset.
2. Press Mode > Custom > Real Time I/Q Baseband > Modulation Type >
This loads a default 4QAM I/Q modulation and displays it in the I/Q Values
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
232
"Accessing the Differential State Map Editor" on page 233
"Editing the Differential State Map" on page 233
Define User I/Q > More (1 of 2) > Load Default I/Q Map > QAM > 4QAM.
228.
228.
Keysight E8357D/67D & E8663D PSG User's Guide
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