This paper presents the design and implementation of a signal simulator that emulates event-related human electrocorticographic (ECoG) signals. This realtime simulator renders a representative model of human ECoG encompassing prominent physiological modulation in the time domain (e.g., event-related potentials, or ERPs) and the frequency domain (e.g., alpha/mu, beta, and high gamma band). The simulated signals were generated in a MATLAB SIMULINK framework and output through a National Instruments PCI card for recording by a standard research-grade ECoG amplifier system. Trial-averaged event-related spectrograms computed offline from simulated signals exhibit characteristics similar to those of experimental human ECoG recordings. The presented simulator can serve as a useful tool for testing real-time brain-machine interface (BMI) applications. It can also serve as a potential framework for future implementation of neuronal models for generation of extracellular field potentials.