Oscillator

An oscillator configured to obtain a frequency output corresponding to a frequency setting value includes: an oscillation circuit portion that receives the frequency setting value; a setting value output portion that outputs a digital value for designating the frequency setting value; an interpolation circuit portion that performs interpolation for a digital value of lower-order bits out of the digital value output from the setting value output portion; and an adder that adds an output of the interpolation circuit portion and a digital value of higher-order bits out of the digital value output from the setting value output portion, wherein a signal output from the interpolation circuit portion is sequential data having first and second values different from each other, and output counts of the first and second values are determined based on a ratio corresponding to the digital value of the lower-order bits.