The Modulation tab enables you to set modulation type, number of symbols, symbol rate, and oversampling factor.

For example, select QPSK, keep the number of symbols as 1024 and the symbol rate as 100 kHz.

For oversampling factor, the default is 4, which means that the symbol rate is oversampled by a factor of 4 before filtering. To modify the default value, unselect the Auto checkbox.

To modify the IQ symbol mapping for phase modulated schemes, click Modify Mapping button. For more information, refer to the Appendix A section of RFmx Waveform Creator Modulation Schemes.

Each modulation scheme supported by RFmx Waveform Creator will have a different modulation tab layout. For more information about the modulation schemes, refer to the RFmx Waveform Creator Modulation Schemes.

Changing Symbol Mapping

Some modulations allow you to configure the symbol mapping of the signal. To edit the symbol mapping, click on Modify Mapping button.

Symbol Mapping Editor

For modulation types that have a fixed mapping between constellation position and symbol, a mapping plot will be presented as shown in the following image.

For all QAM modulations, symbols are plotted in terms of their I-Q values. For all non-differential PSK types, symbols are plotted in terms of their phase values.

Selecting a Symbol

You can enter a specific symbol number in the Symbol control and click Find. This will select the point within the trace that is mapped to the selected symbol value. The selected symbol is shown in a red color.

Note Click on the trace to manually select a desired point.

Changing a Symbol Mapping

Once you have selected a symbol, you can enter a new mapping in the Symbol control and click Set. This will apply the new mapping to the currently selected point.

Resetting the Symbol Mapping

You can reset the symbol mapping to the default values by clicking the Reset To Default button.