Patent attributes
An interpolated signal generating circuit (101) generates interpolated signals (SIG1-SIGN) of two consecutive discrete signals (SIG). N measuring circuits (501) measure interpolated signals. Since the interpolated signals are measurement targets, N-times oversampling measurement can also be performed for the discrete signals. With the oversampling measurement, the frequency spectra of the signal components of the discrete signals are maintained, and only the frequency spectrum of a noise component due to a quantization error increases to a high-frequency band, thereby reducing a noise component per unit frequency. Therefore, removing a high-frequency component from a measurement result from each measuring circuit using a low-pass filter (502) makes it possible to improve the signal-to-noise ratio of the measurement result as compared with a case in which no oversampling is performed.
