Sampling Signals and Poisson’s Formula

We are now going to tackle the problem of sampling analog signals. This operation is a prerequisite of digital signal processing. For example, an analog speech signal must be sampled before it can enter a digital telephone system. A sampler records the level of the signal every a seconds and transforms it into a sequence of impulses (Figure 37.1). An analog-to-digital converter (ADC) codes these impulses as numbers that can be processed digitally.