Patent ID: 6915117

Claim:
In a double conversion transmitter transmitting a radio frequency signal in response to an analog signal input and comprising a modulator having both in-phase and quadrature channels including a first mixer in each channel and providing an intermediate frequency output and a second mixer providing a radio frequency output, said mixers being supplied with first and second mixing signals respectively and mixing signal means for providing said first and second mixing signals, the improvement wherein said mixing signal means comprises: a first frequency divider and a second frequency divider having outputs connected to the mixers in each channel of said first mixer and said second mixer respectively, each of said first and second frequency dividers having a respective, selected and different modulus for dividing an input to the frequency divider by the respective modulus; and a frequency synthesizer providing a signal at a local oscillator frequency to the inputs of said first and second frequency dividers; the modulus of the first and second frequency dividers are related by the expression: f RF =[( M 1 +M 2)/( M 1* M 2)]* f VCO where f RF is the frequency of the radio frequency signal, M1 and M2 are the first and second moduli respectively and f VCO is the output frequency of the frequency synthesizer.