Patent ID: 7480343

Claim:
A transmitter for use in a telecommunications system, comprising: a first mixer that generates an in-phase radio frequency signal by mixing an in-phase baseband signal with a first radio frequency mixer signal; a second mixer that generates an alternative-phase radio frequency signal by mixing an alternative-phase baseband signal with a second radio frequency mixer signal, wherein a relative phase-difference between the in-phase and alternative-phase baseband signals is α radians, wherein |α|≠π/2; combining circuitry that generates an output signal for transmission by combining the in-phase radio frequency signal with the alternative-phase radio frequency signal, wherein the output signal has a frequency, f RF ; and a synthesizer that generates the first and second radio frequency mixer signals, the synthesizer comprising: a voltage controlled oscillator (VCO) that generates a VCO output signal having a frequency, f VCO , such that f VCO = ( n + 1 2 ) · f RF , wherein n=1,2,3, . . . ; and circuitry, including a fractional frequency divider that generates the first and second radio frequency mixer signals from the VCO output signal, wherein each of the first and second radio frequency mixer signals has a frequency equal to f RF , and wherein a relative phase difference between the first and second radio frequency mixer signals is α radians, wherein: n=1; the fractional frequency divider is a divide-by-N fractional frequency divider with N=3/2, and the fractional frequency divider comprises: logic that, for every three successive transitions of the VCO output signal, generates a first fractional frequency divider output signal such that the first fractional frequency divider output signal transitions in response to each of first and second transitions of the three successive transitions of the VCO output signal, and the first fractional frequency divider output signal remains steady in response to a third transition of the three successive transitions of the VCO output signal; and logic that, for said every three successive transitions of the VCO output signal, generates a second fractional frequency divider output signal such that the second fractional frequency divider output signal transitions in response to each of the second and third transitions of the three successive transitions of the VCO output signal, and the second fractional frequency divider output signal remains steady in response to the first transition of the three successive transitions of the VCO output signal.