Patent ID: 8909686

Claim:
A discrete Fourier calculation device comprising: a twiddle factor table storage that stores therein a twiddle factor table that associates twiddle factors placed on a circumference of a unit circle on a complex plane with phases of the corresponding twiddle factors; a correction value specifier circuit that specifies first and second correction values for correcting a phase of an input signal in accordance with an amplitude of the input signal; a generator circuit that corrects the phase of the input signal by using the specified first and second correction values to generate first and second phases; an adder circuit that adds an arbitrary phase, which is a phase corresponding to an arbitrary twiddle factor stored in the twiddle factor table, to each of the generated first and second phases; and a rotation calculator circuit that acquires, from the twiddle factor table, first and second twiddle factors corresponding to the first and second phases to each of which the arbitrary phase is added by the addition unit and sums the acquired first and second twiddle factors to acquire a rotation calculation result on the input signal.