A processing circuit includes: a clock generating circuit configured to generate, based on a reference clock signal and a frequency division ratio, a first clock signal; a frequency dividing and delay circuit configured to generate a second clock signal to have a first phase difference with the reference clock signal by dividing the frequency of the first clock signal and delaying the first clock signal based on a phase shift set signal and the frequency division ratio; an analog-to-digital converter circuit configured to convert an analog signal into a digital signal based on the first clock signal and a conversion trigger signal indicating a sampling period and a conversion period; and a control circuit configured to generate the conversion trigger signal to have the same cycle as the second clock signal based on the frequency division ratio and the first clock signal.