Maths, Physics Revision Physicss Maths Physics Physics A Level Physics Home Maths Maths Revision hut Electromagnetic Spectrum These days TV and Radio are using Digital signals.  It is important that you understand the difference   between analogue and digital  Analogue signals change  gradually like waves Digital signals are in steps, they are either on or off. Digital signals are either on or off (1 or 0) The analogue signal is “sampled” at certain time  periods to “read” the analogue signal. The level of  the analogue signal is converted into binary pulses.