A digital signal is a signal that can be represented as a sequence of discrete (digital) values. In our time, the most common binary digital signals ( bitstream ) due to the ease of coding and usability in binary electronics. To transmit a digital signal over analog channels (for example, electrical or radio channels), various types of manipulation ( modulation ) are used.
Application
An important property of the digital signal, which determined its dominance in modern communication systems, is its ability to fully regenerate in a repeater (up to a certain threshold signal-to-noise ratio). When a signal arrives at the repeater with little interference, it is digitized, and the repeater forms the signal again, completely eliminating the distortion. The analog signal can only be amplified along with the noise imposed on it.
On the other hand, if a digital signal comes with great interference, it cannot be restored ( steep cliff effect ), while some information can be extracted from a distorted analog signal, albeit with difficulty. If we compare the cellular communication of the analog format ( AMPS , NMT ) with the digital connection ( GSM , CDMA ), then with interference on the digital line, whole words sometimes fall out of the conversation, while on the analog line you can have a conversation, albeit with interference.
The way out of this situation is to regenerate the digital signal more often by inserting regenerators into the disconnection of the communication line, or to reduce the length of the communication line (for example, to reduce the distance from the cell phone to the base station , which is achieved by a more frequent arrangement of base stations on the ground).
The use of digital information verification and recovery algorithms in digital systems allows to significantly increase the reliability of information transfer.
See also
- Analog signal
- Discrete signal
- Signal (technology)
- Quantization (signal processing)
- Signal processing
- Analog signal processing
- Digital signal processing
- Analog-to-digital converter
- D / A converter