Agilent Technologies ESG series, User And Programming Manual, Page: 45 / 446

Real-Time I/Q Baseband Generator User’s and Programming Guide 2-17
HP ESG Family Signal Generators Using Functions
Options UN8 and 202 Mapping Symbol Positions with the I/Q Table Editor
Entering I and Q Values
Next you will enter the coordinates of each symbol. The position of a symbol is defined by a
pair of values (one representing I and the other representing Q).
Both the 4QAM I/Q map shown on page 2-16 , and the map you create in this example have
four symbols. Please note, however, that the 4QAM I/Q map uses only two unique values
(
−
1.0 and 1.0) to create those symbols, while this example uses the following four unique
values: 0.5, 1.0,
−
0.5, and
−
1.0. It is not the number of values that defines how many
symbols a map has, but how those values are combined.
NOTE The number of bits per symbol can be expressed using the following formula.
Because the equation is a ceiling function, if the value of x contains a fraction,
x is rounded up to the next whole number.
Where x = bits per symbol, and y = the number of I/Q states.
The following figure summarizes the process of entering values in the I/Q table editor.
Detailed steps begin on the next page.
Symbol Data Bits 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
2. Use the keypad to enter the desired value.
3. Press Enter to accept the value.
1. Use the arrow keys to highlight
where you wish to enter a value.
Because there
are no values in
an empty table,
this list is empty.