SIGNAL PROCESSING APPARATUS FOR MEASURING MACHINE

There is provided a signal processing apparatus, which can perform measurement with a wide dynamic range and high resolution, for a measuring machine. A first analog-to-digital (AD) converter AD-converts a sensor signal into an upper digital signal. A first digital-to-analog (DA) converter DA-converts the upper digital signal into an upper analog signal. A first combining unit generates a lower analog signal by subtracting the upper analog signal from the sensor signal. An amplifier generates a magnified lower analog signal by amplifying the lower analog signal. A second AD converter AD-converts the magnified lower analog signal into a lower digital signal. A second combining unit combines the upper digital signal regarded as upper side digits with the lower digital signal regarded as lower side digits.