How does digital technology work?
To understand how digital radio works, you must go back to basics and know how digital technology works.
Digital technology involves processing numbers electronically. It generates, stores and processes data in two states; positive, represented by the number 1, and negative, represented by the number 0. Essentially, digital technology expresses data as a string of 1’s and 0’s.
Once the audio is digitised, it can reach the listeners primarily through two means – by direct transmission using DAB (Digital Audio Broadcasting) technology or through the Internet. Here we are discussing DAB.
Analog technology, on the other hand, conveys data as electronic signals of varying frequencies and amplitudes. Waves of a given frequency carry these signals. These get to the listener through the air using AM (Amplitude Modulation) or FM (Frequency Modulation) technologies.
How does digital radio work?
Digital radio, therefore, broadcasts radio via a network of terrestrial transmitters. It has no frequencies, which means audio interference does not happen.
Digital radio works by combining MPEG and COFDM technology.
MPEG (Moving Picture Experts Group – the body that sets up the standards) is an audio compression system. The system basically discards sounds which the listener cannot hear. These include very quiet sounds which might be masked by louder sounds. Thus, the digital technology does not have to broadcast as much digital information.
CODFM (Coded Orthogonal Frequency Division Multiplexing) technology eliminates interference, which would disturb an FM reception. So, the whole country can use the same frequency.
Digital radio combines several service areas in a multiplex so that radio stations do not need their own frequency. The multiplex can carry audio, data and an in-built protection system against transmission errors.
Digital radio therefore sends program signals broken into fragments and digits. The transmitter sends each fragment many times so there is a lower change of the signal being lost. The receiver then pieces together the fragments who have had a successful journey to make an uninterrupted program signal.