Digital signals consist of patterns of bits of information. These patterns can be generated in many ways, each producing a specific code.
Modern digital computers store and process all kinds of information as binary patterns. All the pictures, text. sound and video stored in this computer
are held and manipulated as patterns of binary values.
The main advantage of digital signals over analog signals is that the precise signal level of the digital signal is not vital. This means that digital signals
are fairly immune to the imperfections of real electronic systems which tend to spoil analog signals. As a result, digital CD's are much more robust than analog LP's.
Codes are often used in the transmission of information. These codes can be used either as a means of keeping the information secret or as a means of breaking the
information into pieces that are manageable by the technology used to transmit the code, e.g. The letters and numbers to be sent by a Morse code are coded into dots