Patent ID: 7787773

Claim:
A radar system comprising: a system for oscillating a radio signal, the radio oscillating system comprising; an optical modulator for oscillation, a modulating means for inputting a modulating signal of a frequency of fm into the optical modulator to modulate a carrier wave so as to superimpose sideband waves onto the carrier wave at positions shifted with respect to the frequency of the carrier wave by the frequency fm, an optical receiver for oscillation for receiving beam from the optical modulator and for converting the beam to an electrical signal, said optical receiver having a band higher than 2fm and lower than 4fm, and a radiating means for receiving the electrical signal output from the optical receiver and for radiating a radio signal of a frequency of 2fm based on the electrical signal without further inputting of the electrical signal into the optical modulator, wherein an input voltage Vp-p applied on the optical modulator is 1.0 times or more and 1.99 times or less of a half-wavelength voltage Vπ of the optical modulator; and receiving means for receiving a signal reflected from an object, wherein the received signal and the radio signal are input into signal processing means to obtain information concerning the object.