Digitizers convert the samples of an analog signal into digital values using analog to digital converters (ADCs). The resolution of the ADC is the number of bits it uses to digitize the input samples. For an n bit ADC the number of discrete digital levels that can be produced is 2n. Thus, a 12 bit digitizer can resolve 212 or 4096 levels.
Basic Information on A/D, Digitizers, Transient Recorder Products and the hardware details
The option (M4i.22xx-ir40m) for the high-speed 22xx series of digitizer products increases their input sensitivity and therefore absolute resolution for low amplitude signals in the 40 mV up to 0.5 V range. The alternative front-end option has to be ordered with the card