You can access all these blocks from the '''Parts Menu'''. Some of the waveform generator devices are categorized as "voltage source" devices in the Device Manager's point of view. A number of the virtual blocks are native XSPICE models. You can find their models as "process models" in the Device Manager. Many others are "subscircuit models". You can open up, view and even modify their Netlist codes. Some other blocks like the generalized analog and digital filters do not have editable Netlist codes.
== A Note on the SPICE Simulation of Virtual Blocks ==
Most of the virtual blocks can be used in both transient and AC analysis tests. Obviously, nonlinear operations must be performed in the time domain. For example, you can see the performance of voltage controlled oscillators (VCO) only in a transient test, and using them in conjunction with AC frequency sweep analysis is meaningless. The same is true for frequency conversion blocks such as frequency multipliers. In addition, certain blocks such frequency conversion blocks may require harmonic wave input signals and may not work properly with arbitrary waveforms.