The present paper exposes a novel description of the effect of a pulse generator on a double integrator representing one axis of rotation for a space vehicle. By considering the difference between the angular velocity obtained with zero-order-hold (ZOH) actuator and the one with a PWM actuator, a perturbation operator expressing the influence of the PWM on the angular speed is defined. Using this configuration in a linear fractional representation (LFR), a stability analysis allows comparing LMI-based and IQC-based stability results for a one degree of freedom rotating body with uncertain PWM and saturation and permits dwelling on improvements to make for further analyses.