Patent ID: RE42043

Claim:
Radiofrequency transmitter, of the type supplied with two signals in base band and in quadrature, i(nT) and q(nT), which are images from two binary streams representing information to be transmitted, the radiofrequency transmitter: means ( 1 ) of transposition into an intermediate frequency and of digital processing, that provide a first transposition into the digital domain, at an intermediate frequency ω 0 , for said base band signals, and generating, by combination, two signals at the intermediate frequency and in quadrature; means ( 2 ) of direct conversion, providing a second transposition into the analog domain, after multiplication by a frequency ω 1 , followed by a summation, of said two signals at the intermediate frequency and in quadrature, in a way that generates a resultant signal which is finally modulated around a frequency ω 2 , where ω 2 = ω 0 +ω 1 wherein said two signals at the intermediate frequency and in quadrature are of the form: m 1 (t)=i(t)·cos(ω 0 t)−q(t)·cos(ω 0 t) m 2 (t)=−i(t)·sin(ω 0 t)−q(t)·cos(ω 0 t) and in that said resultant signal is of the form m(t)=g 1 ·m 1 (t)·cos(ω 1 t+θ 1 )+g 2 ·m 2 (t)·sin(ω 1 t+θ 2 ) where g 1 and g 2 are the respective gains for the two channels in quadrature of said means of direct conversion θ 1 and θ 2 are the respective phase shifts for the two channels in quadrature of said means of direct conversion.