Mixer device with image frequency rejection

Mixer device with image frequency rejection, comprising:

• mixing means for forming a first signal by mixing an input radio signal with a first wave of frequency fO delivered by a local oscillator and a second signal by mixing the input radio signal with a second wave of frequency f.sub.O delivered by the local oscillator and having a phase lag of 90.degree. with respect to said first wave;
• means of algebraic summation of third and fourth mutually phase-shifted signals obtained from said first and second signals, in order to produce an output signal possessing, at an intermediate frequency f.sub.I, a phase representative of a phase possessed by the input radio signal at a communication frequency f.sub.C of the form f.sub.O -f.sub.I or f.sub.O +f.sub.I, with rejection of the phase possessed by the input radio signal at an image frequency 2f.sub.O -f.sub.C ;
• phase-shifter means producing said third signal by filtering an algebraic sum of the first and second signals with a transfer function A(f);
• and
• means for producing said fourth signal by applying to one of said first and second signals a transfer function B(f) such that, at the intermediate frequency f.sub.I, the ratio A(f.sub.I)/B(f.sub.I) has modulus 1/.sqroot.2 and argument .+-.45.degree. or .+-.135.degree..