The inputs and outputs of the communications blocks support various data types. For some blocks, changing to single outputs can lead to different results when compared with double outputs for the same set of parameters. Some blocks may naturally output different data types than what they receive (e.g. digital modulators) a signal. Refer to the individual block reference pages for details.
The Communications System Toolbox™ Block Support Table is available through the Simulink® model Help menu. The table provides information about data type support and code generation coverage for all Communications System Toolbox blocks. To access the table, select Help > Simulink > Block Data Types & Code Generation Support > Communications System Toolbox.
You can also access the Communications System Toolbox Data Type Support Table by typing showcommblockdatatypetable at the MATLAB® command line.