Patent ID: 8483332

Claim:
An oscillating apparatus which controls an oscillation frequency in accordance with an input signal, the oscillating apparatus comprising: a detection unit which detects a frequency offset between the input signal and a reference signal, the frequency offset comprising a first frequency offset and a second frequency offset, wherein the detection unit includes: a first detection unit configured to detect the first frequency offset and a second detection unit configured to detect the second frequency offset; a voltage control unit which converts the frequency offset detected by the detection unit to a value of a code having a predetermined number of bits, and converts the value of the code to a value of a voltage; and a voltage-controlled oscillator which controls an oscillation frequency thereof in accordance with the value of the voltage obtained by the voltage control unit; wherein the voltage control unit changes, based on a portion of the detected frequency offset, a range of values of the frequency offset which are to be converted to different values of the code with the predetermined number of bits, as well as changes a range of values of the voltage which are to be converted from the different values of the code having the predetermined number of bits.