Abstract: A versatile signal generator for generating digitally modulated test signals computed in real-time is provided. Each of the blocks ol the versatile signal generator, including the MUX, coder, map, filter, re-sampler, and modulator, are implemented in a sufficiently flexible manner so as to allow ready configuration to produce any of a variety of digitally modulated signals as well as high quality analog modulated signals. Each of the blocks may be implemented using ASICs and RAM that allow to obtain high symbol rates while being capable of being reconfigured for different test signals as needed. The versatile signal generator has a real time input for receiving input data to modulate the test signal in real time.