A signal processing device (100), preferably an undersampling ADC using coherent sampling, is presented for processing a signal (102) , the signal processing device (100) comprising a comparator unit (105) for comparing the signal (102) with a reference signal (106), a generation unit (105, 130) for generating digital result signals (110) indicative of the result of the comparing, an evaluation unit (112) for determining transition times of the digital result signals (110), and an output signal calculation unit (115) adapted for calculating essentially uniformly spaced output signals (116).