Local oscillator

A local oscillator comprising:

• a digitally-controlled oscillator capable of controlling an oscillating frequency of an oscillating signal based on an oscillator control value which is a digital value;
• a frequency multiplier configured to multiply a frequency of a reference signal by 2 and output a multiplication reference signal;
• a phase data generator configured to output phase data of the oscillating signal in synchronization with the multiplication reference signal, the phase data being a digital value;
• an adder configured to add correction data to first setting frequency data for setting the oscillating frequency and output the addition result as second setting frequency data;
• an accumulator configured to accumulate the second setting frequency data in synchronization with the multiplication reference signal, and output the accumulated second setting frequency data as reference phase data;
• a subtractor configured to subtract the phase data from the reference phase data, and output a subtraction result as phase error data;
• a loop filter configured to filter the phase error data and output the oscillator control value;
• a first multiplier configured to multiply the phase error data by +1 or −1 according to the reference signal, and output a multiplication result as first data;
• a low pass filter configured to filter the first data and output second data;
• an absolute value calculating circuit configured to output an absolute value of the second data as phase offset data;
• a controller configured to output 0 as third data until a predetermined time elapses, and output the phase offset data as the third data after the predetermined time has elapsed;
• and
• a second multiplier configured to multiply the third data by +1 or −1 according to the reference signal and output the multiplication result as the correction data.