The concept of the sector bound nonlinearity has been considered for frequency domain stability analysis of linear single-input single-output (SISO) and decoupled multi-input multi-output (MIMO) systems associated with the fuzzy logic controller. For analysis of the fuzzy logic controller, system's model is considered to be available in transfer-function form. But, for generation of the fuzzy logic controller, no model description is necessary. The drawback of the previous work on analysis of the fuzzy logic controller is overcome in the present work and a most generalised Nyquist-type version for stability analysis is given.