Patent ID: 7953566

Claim:
A method of calculating electromagnetic interference reduction through spectrum diffusion that is a means of reducing electromagnetic interference, the method comprising: inputting clock frequency of a target electromagnetic interference signal, modulation frequency used for said spectrum diffusion, maximum frequency shift, and measurement bandwidth of a measurement device as data from an input unit; calculating electromagnetic interference reduction for every frequency which appears by modulation; calibrating said electromagnetic interference reduction in consideration of influence by said measurement bandwidth of said measurement device; and calibrating said electromagnetic interference reduction in consideration of influence by a filter property of a band filter of said measurement device, wherein said calibrating said electromagnetic interference reduction in consideration of influence by said measurement bandwidth of said measurement device comprises: adding one to an integral part of a value obtained by dividing said bandwidth by said modulation frequency, setting the obtained value as the number of frequency spectra for calculation of electromagnetic interference reduction, and performing calibration of said electromagnetic interference reduction by using a value obtained by adding up amplitudes of all frequency spectra, wherein said calibrating said electromagnetic interference reduction with influence by a filter property of a band filter of said measurement device comprises: setting said filter property of said band filter in advance by using a typical value of said measurement device, and performing calibration of said electromagnetic interference reduction by using reduction value by said filter property for every target frequency.