Signals are basically of two types - Analog and Digital. Analog Signals have continuous signal for every instant of time. They are Continuous-time and continuous-valued signals. a major chunk of the signals around us are analog such as the voice when we speak, the vibrations created by a mechanical device etc.

The other kind of signals, which are the digital signals are mostly used in elctronic device communications. Outside he elctronic world the most convenient way to transmit signals is analog. Digital signals have a fixed value for certain periods of time. It is also possible that a digital signal may not have a value at some instance of time.

Now the use of electronic devices is becoming so widespread, that almost every device needs conversion between analog and digital signal formats. Conversion of an analog signal to a digital signal requires sampling of the analog signal so as to produce an equivalent digital signal. Click the Next button to learn more about sampling and other related concepts.