*1 RB sets the DAC's full-scale peak-to-peak swing and the DAC's output bias level
*2 Shunt resistor RS scales down the DAC's peak-to-peak voltage without affecting the bias level
*3 The "DAC Peak Back-Off" refers to how close the peaks of the DAC's output signal come to the DAC's full-scale output voltage
*4 The Crest Factor that is inputted sets the backoff level between the DAC Peak Output Level and the RMS Level of the carrier
Therefore: DAC Fullscale Level = RMS Level + Crest Factor + DAC Peak Back-Off
In general, the signal peaks need to be backed off from the DAC's full-scale level by a few dB. The amount of back-off required depends on the desired/acceptable signal distortion
*5 Modulator Voltage Gain is defined as the dB difference between the voltage level on the I or Q input (generally these are equal) and the RF Output