Patent ID: 7333554

Claim:
A communication system by radio waves with frequency modulation, comprising: a signal processing unit ( 120 ), a transmission stage ( 110 ) for transmitting a transmission signal in response to a modulated control signal and in response to a first frequency reference signal, comprising: a phase-locked loop ( 112 ) including a low-pass filter ( 117 ), and a modulator ( 130 ) connected between the processing unit ( 120 ) and the transmission stage ( 110 ) for forming the modulated control signal in response to an output signal of the processing unit ( 120 ) and in response to a second frequency reference signal, a single local oscillator ( 174 ) in communication with: a phase-locked loop ( 170 ) which comprises a first frequency divider ( 179 ) for selecting the first reference frequency to be applied to the transmission section; and a second frequency divider for selecting the second reference frequency which is applied the modulator, wherein at least one of the first and second frequency dividers possesses a fractional division ratio.