Patent ID: 7518377

Claim:
A measurement apparatus for measuring a fluctuation of a voltage level of an input signal with respect to a reference voltage, where the voltage level of the input signal fluctuates with respect to the reference voltage having a predetermined high voltage level, the measurement apparatus comprising: a high-frequency passage section for allowing passage of a high-frequency component of a predetermined first band of the input signal; a reference voltage dividing section for dividing a voltage level of the reference voltage at a predetermined voltage dividing ratio; a signal voltage dividing section for dividing the voltage level of the input signal at the voltage dividing ratio; a low-frequency passage section for allowing passage of a low-frequency component of a second band of a differential signal that is according to a difference between a voltage level of the reference voltage outputted from the reference voltage dividing section and a voltage level of the input signal outputted from the signal voltage dividing section, the second band being lower than the first band; a composite section for combining a signal outputted from the high-frequency passage section and a signal outputted from the low-frequency passage section; and a measurement section for measuring a signal outputted from the composite section.