In this work, the ground bounce noise has been modeled and analyzed in frequency domain, for both synchronous and GALS (globally asynchronous, locally synchronous) systems. The analysis has been performed analytically, and validated by numerical simulations in MATLAB. Package parasitics and power distribution network have been coarsely modeled by a simple lumped model, while switching currents have been modeled as periodic triangular pulses. Dominant components of spectrum are determined, and the impact of their distribution on the requirements for substrate modeling has been discussed. It has been concluded that resistive substrate approximation introduces large errors for systems with small decoupling capacitances, while it can be satisfactory for systems with large decoupling capacitances.