digital instantaneous Frequency Measurement

hello every one, im implementing ifm receiver using xilinx system generator , i have completed hilbert transform block , and auto correlation block and im not to implement my phase lut block(phase mapping block) , if any one has any input to the model ,kindly reply me my ifm block diagram is

my phase mapping block is

</matlabcentral/answers/uploaded_files/57209/dvdv.jpg> im not understanding "q over i" block in phase lut block. kindly guide me.

[Sandeep Kumar]