A characterization system includes a signal detector. The signal detector includes a first conversion unit configured to receive, from a first device, a first device output signal including N possible discrete pulse amplitudes and generate a plurality of detected signals based on a plurality of threshold amplitudes respectively. The signal detector further includes a second conversion unit configured to generate a first conversion output signal and a second conversion output signal based on logic values included in the plurality of detected signals and provide first and second conversion output signals to an analysis unit for generating one or more measurements of the first device. The first and second conversion output signals include M1 and M2 possible discrete pulse amplitudes respectively. M1 and M2 are integers less than N.