Patent ID: 7557662

Claim:
An oscillating apparatus comprising: a first oscillator for generating a first oscillation signal, said first oscillation signal having a first frequency of (f 1 +c·ΔV) in which the first frequency is variable through Δf with respect to a center frequency of f 1 in response to a supplied voltage; a second oscillator for generating a second oscillation signal having a second frequency of f 2 ; a first frequency varying unit for generating a third oscillation signal having a frequency of f 3 , the frequency of said third oscillation signal being a times as large as that (f 1 +c·ΔV) of the first oscillation signal; a second frequency varying unit for generating a fourth oscillation signal having a frequency of f 4 , the frequency of said fourth oscillation signal being b times as large as that (f 2 ) of the second oscillation signal; a frequency synthesizing unit for synthesizing said third and fourth oscillation signals to generate a fifth oscillation signal, said fifth oscillation signal including a frequency component of f 5 of an absolute value of a sum of or a difference between said third and fourth oscillation signals (f 5 =|f 3 ±f 4 |); and a filtering unit for removing frequency components of said f 3 and f 4 from said fifth oscillation signal wherein at least one of said first and second frequency varying units includes a cumulative adder, a direct digital synthesizer or a phase-locked loop (PLL) waveform generator.