MIXER ARRANGEMENT COMPRISING FIRST AND SECOND QUADRATURE MIXER STAGES

摘要

Mixer arrangement (M) comprising first and second quadrature mixer stages (M1 and M2) to which quadrature mixing signals are applied from an oscillator circuit (F0), these two mixer stages (M1 and M2) being coupled to a superposition circuit (S0). To suppress interferences occurring in the output signal of the superposition circuit due to oscillator crosstalk or leakage and/or a d.c. offset of the mixer stages (M1 and M2) which are supplied with mixing signals by the oscillator cirucit F0, the quadrature components of these interferences being in phase with the quadrature mixing signals are measured by means of first and second synchronous detectors (SD1 resp. SD2) to which detection carriers are applied in an in-phase or an anti-phase relationship with respect to the quadrature mixing signals. After sign inversion these quadrature components are fed back to the inputs of the two mixer stages (M1 and M2), resulting in an interference negative feedback.