In this report, the author studied the methodology of distortion-true software modeling for RF (radio frequency) in a DSSS W-CDMA system. A complete end-to-end testbed based on the Welkin RF system is built by SystemView with specifications from real world RF components. This testbed includes digital baseband transmitter, RF transmitter, wireless channel, RF receiver, and baseband receiver for WLAN applications. Several implementation issues will be discussed. Various time/frequency domain analysis methods help to understand the non-linearity of real RF components in each stage and provide a reference to the hardware design. To support the capability of multi-domain simulation, Matlab custom tokens were integrated. The simulation results show the effects of noise figure introduced by RF on the receiver's sensitivity.