Step size (time duration at each frequency step) and frequency offset from the carrier are user-defined. The frequency offset must be within the ±40 MHz bandwidth of the signal generator if using the internal Arb, or ±500 MHz if using the N603xA/M933xA or N824xA Arb. Selecting the FM Step Modulation Type displays a table as shown in the figure below.
For the trapezoidal and raised-cosine built-in pulse types the step size should sum to equal the pulse Width (100%-100%). For custom profile and custom I/Q pulse types the step size should sum to equal the time duration from the first point of data through to the last point of data. If the step size does not equal the pulse width the FM steps will be padded (if not enough steps), or truncated (if too many steps). Refer to the padded and truncated diagram for more information.
To create the FM Step table:
Select FM Step from the Modulation Type drop-down list box.
Place the mouse pointer in the FM step table and click the right mouse button.
Click 
New Items
in the menu.
Enter the number of
index items
desired using the dialog box.
Enter the and for each index item.
The following diagram shows the frequency offset and time duration relationship for the table entries in the form shown above.
