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Real-Time I/Q Baseband Generator User’s and Programming Guide 2-23
HP ESG Family Signal Generators Using Functions
Options UN8 and 202 Building a Customized FSK Modulation with the FSK Table Editor
Creating a Unique FSK File of Frequency Deviations
There are two ways to create a custom FSK file. You can either define the frequency
deviations using completely original data (see "
Using Original Data " below), or you can
load and modify a default FSK pattern (see “ Modifying a Default FSK Pattern ”
on page 2-24).
Using Original Data
Use the following instructions to create an example of an APCO25 C4FM customized
continuous 4-level FSK signal with two bits per symbol.
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 frequencies.
When you create new frequency values (rather than edit existing data), it is often easier to
start with an empty table. To clear the existing frequency values from within the Define
User FSK menu, press
More (1 of 2)
>
Delete All Rows
>
Confirm Delete Of All Rows
.
The following figure defines the areas of the display. As you enter frequency deviation
values, the numbers will display in the active entry area (if you make a mistake, use the
backspace key and then retype). Follow the steps below:
1. For the first frequency deviation value, enter 600 Hz. Note that each time you enter a
value, the
Data
column increments to the next binary number, up to a total of 16 data
values (from binary 0000 to binary 1111).
Unstored custom frequency values
Frequency deviation active entry area
Frequency terminator softkeys