A general method for the analysis of frequency-modulation reticles is presented. The formulation starts by introducing the spoke function f(p) as an offsetting factor to the phase angle 0. Through the process of coordinate transformation, the output signal after demodulation is obtained. The result contains two main parts: the first part represents the contribution from the basic configuration of a straight-edge spoke; the second part, containing the term df/dp, represents the modifying effect of changing the spoke edge to an arbitrary curve. By means of four examples, the method is shown to be valid in verifying the dependence of the output signal on the spoke shape. Any frequency-modulation reticle can be analyzed by this general method so long as its corresponding spoke function is known.