Circuit device, oscillator, electronic apparatus and vehicle

A circuit device comprising:

• an oscillation signal generation circuit configured to, using frequency control data and a resonator, generate an oscillation signal with an oscillation frequency set by the frequency control data;
• and
• a processing circuit that receives the oscillation signal and a reference signal, and that outputs the frequency control data to the oscillation signal generation circuit,
• wherein
• the processing circuit includes
• a counter configured to perform, based on the oscillation signal, a count process at a cycle set by a frequency control word, and
• a latch circuit configured to hold a count value of the counter based on the reference signal, and
• the processing circuit
• performs a loop filter process on a phase comparison result based on output data of the latch circuit to output the frequency control data,
• holds information based on the phase comparison result when holdover due to disappearance or a defect of the reference signal is detected, and
• outputs the frequency control data based on the information held, in a holdover period.