Sensor device

A sensor device comprising:

• a sensor unit that generates a detection signal according to an entered sinusoidal analog signal, the detection signal having an amplitude matching a physical quantity to be detected and also having the same detection frequency as the analog signal;
• a reference signal generating unit that generates a reference signal having the detection frequency, according to the entered analog signal;
• a first analog-digital converting unit that converts the detection signal to a digital signal in synchronization with a clock signal;
• a second analog-digital converting unit that converts the reference signal to a digital signal in synchronization with the clock signal;
• a demodulating unit that multiplies each of two sinusoidal synchronization signals having the detection frequency and the detection signal converted to a digital signal together, the phases of the two sinusoidal synchronization signals being shifted from each other by one-fourth of a cycle, and generates two demodulated signals in which a harmonic component has been removed from results of the multiplication;
• and
• a correcting unit that corrects the demodulated signals according to the reference signal converted to a digital signal so that a variation in the demodulated signals is suppressed, the variation being caused by a variation in a phase of the clock signal;
• wherein
• a correlation exists between a phase of the detection signal with respect to the analog signal and a phase of the reference signal with respect to the analog signal, and
• the correcting unit
• calculates a change in a relative phase of the detection signal with respect to the synchronization signals according to a change in a relative phase of the reference signal with respect to the synchronization signals, and
• corrects at least one of the two demodulated signals so that the relative phase of the detection signal, the relative phase being represented by the two demodulated signals, approaches a phase in which the calculated change in the relative phase is canceled.