Sample rate

By their nature, ADCs are discrete time devices, delivering new output results only periodically at a frequency called the sample rate. In some cases the input may be essentially instantaneously sampled, and in that case each ADC output code can be associated quite directly with a particular input sampling time. In other cases the input may be intentionally averaged over a long period to reduce noise, and each ADC output code is then associated with one of these periods (Fig. 6.3b). In either case the rate of output code occurrence is an important property of the converter and, along with the resolution, defines the basic suitability of the converter for a particular application.