An analog to digital converting device is proposed for generating a digital output signal of an RF analog input signal. The device comprises a first analog to digital converter stage, a mixer, a second analog to digital converter stage and a digital filter. The first analog to digital converter stage generates a first and a second output signal. The first output signal is inputted in the filtering means. The second output signal is being down-converted to a signal with an intermediate frequency or DC. Thereafter, this down-converted signal is being fed to the second analog to digital converter stage. The digital output signal of this second stage is further processed together with the first digital output signal in the digital filter to a digital signal representative of the analog input signal.