According to magneto-optic (MO) Bragg diffraction and modulation effects in the interaction between the amplitude-modulated magnetostatic forward volume waves and guided optical waves,the operating principle of space-integrating MO correlators is described.The analytic expressions for the envelope of detected band-pass signal associated with normalized correlation integral are obtained and used to analyze the performance of the space-integrating MO correlators dependent on the intensity of microwave RF signals.It is shown that,in the range of small signals,the peak value of normalized envelope is approximately proportional to the RF-driven power and the MO correlation can be strictly realized with the processing gain of 20 dB or more.