In view of the disadvantages of the cross product frequency discrimination method for FM signal digital demodulation

such as excessive occupation of hardware resource

low accuracy and limited application to narrowband signal demodulation only

this paper adopts an improved algorithm

which avoids computing the approximate the inverse tangent value and reduce to the maximum the algorithm complexity by changing the processing of the signals in I and Q channels

thus realizing the demodulation with less occupation of resource

higher accuracy and suitability for both narrowband and broadband FM signals.Simulation by Matlab and implementation on the platform of Quartus II 11.0 software based on the Cyclone III chips verify the feasibility of this algorithm.