1. A noise suppression component selecting method for selecting a noise suppression component suitable for noise suppression in a digital circuit, the method comprising: a step of determining an amplitude and phase of a signal at a given position of the digital circuit when an input signal is input to the digital circuit; a step of determining an amplitude and phase of the signal at the given position when the input signal is input to the digital circuit in the case where the circuit includes each of a plurality of noise suppression components; a comparing step of comparing, for each order of fundamental and harmonic components, between the amplitude and phase of the signal at the given position determined in the case where the digital circuit includes each of the plurality of noise suppression components and the amplitude and phase of the signal at the given position determined in the case where the digital circuit does not include each of the plurality of noise suppression components; a scoring step of scoring, for each order of fundamental and harmonic components, the compared amplitude and phase obtained in the comparing step determined in the cases where the digital circuit includes each of the noise suppression components and does not include each of the noise suppression components; and a summing step of calculating a total score by summing the scored amplitude and phase by weighting for each order.