Patent ID: 7308240

Claim:
A numerical control oscillator comprising: a phase accumulator for accumulating input phase difference data to generate phase data, said phase accumulator including a register for storing and outputting said phase data, and a calculator for one of adding and subtracting said input phase difference data and said phase data from said register; and a memory for storing a phase/amplitude conversion table to output amplitude data corresponding to said phase data generated by said phase accumulator, said numerical control oscillator outputting a signal of a sampling frequency Fs, wherein: if an upper limit of a desired frequency setting interval of an output signal is FD and, K and L are arbitrary integers, said calculator of said phase accumulator is performing one of adding and subtracting said input phase difference data and said phase data from said register by a modulo operation taking a nearest integer of M as a modulus, where M=Fs/FD×K/L; and said phase/amplitude conversion table outputs a signal set to a frequency setting interval of a dF step, where dF=FD/K×L.