Patent ID: 8519872

Claim:
An analog-digital converting method for converting an analog signal into a digital signal using a plurality of analog-digital converters provided with a sampling clock whose phase is shifted by a prescribed period for each analog-digital converter, the analog-digital converting method comprising: measurement of measuring, in advance, frequency characteristics of each of the analog-digital converters; sampling of sampling the analog signal using the analog-digital converters; intra-group correction of, for each of a plurality of groups obtained by dividing a plurality of measurement signals generated using the analog-digital converters, generating measurement signals that would be obtained when the frequency characteristics of the corresponding analog-digital converters are ideal by multiplying the measurement signals by a correction coefficient that is based on the frequency characteristics of all the analog-digital converters in the group; and inter-group correction of correcting and combining the frequency characteristics of the groups based on a difference in the frequency characteristics between the groups formed during the intra-group correction, to generate a frequency spectrum of the digital signal.