Digital signals and sampling The apparent simplicity of a digital signal is centred on the signal having just two states, on or off, 1 or 0. This is unlike the analogue signal, which will contain many variations in levels which must be preserved in any processing. To generate a digital signal, samples of an analogue signal are taken as a series of numbers. This series of numbers contains all the information required to regenerate the original signal. Converting from analogue to digital is known as coding and reversing the process is known as decoding.