Patent ID: 7812651

Claim:
A PLL apparatus comprising: a voltage-controlled oscillation unit oscillating a frequency signal according to a supplied direct-current voltage; an analog/digital conversion unit sampling an external standard signal which is a stable sinusoidal signal, based on the frequency signal from said voltage-controlled oscillation unit, and outputting a sampling value as a digital signal; an orthogonal transformation unit applying orthogonal transformation to the digital signal by an orthogonal transformation unit to extract a real part and an imaginary part which are complex expression of a phase vector equivalent to a phase difference between the frequency signal and the standard signal; an angular velocity calculation unit calculating an angular velocity of the vector based on time-series data of the real part and the imaginary part extracted by said orthogonal transformation unit; and a means for supplying said voltage-controlled oscillation unit with the direct-current voltage according to the angular velocity calculated by said angular velocity calculation unit.