. What is Digital signals
A digital signal is a discontinuous function of time, in contrast to an analog signal, wherein current or voltage value varies continuously with time.
Such a signal is usually in the form of pulses. Each pulse has two levels of current or voltage, represented by 0 and 1. Zero (0) of a digital signal refers to open circuit and (1) of a digital signal refers to closed circuit. Zero (0) is also referred to as ‘No’ or space and (1) is referred to as ‘Yes’ or mark. Both 0 and 1 are called bits.