For communication and transmission of messages using signals that differ from each other. There are continuous (HC) and discrete signals (DS).
- 1 Features continuous signal
- 2 What is discrete
- 3 Differences between the two types of signals
Features continuous signal
If a discrete signal is quantized in both time and level, then it is called a digital signal.
A signal is considered continuous if it can have any value within the specified limits. From a mathematical point of view, this means that the NA can be represented as a continuous function. Examples of such a signal is a signal received from a microphone about the pressure of a sound wave on its membrane or a signal from a thermocouple about a measured temperature.
Analogue systems for transmitting information using NS have the following disadvantages:
- reduced noise immunity - this property is due to the fact that, due to the continuity of the system, the noise entering the signal cannot be distinguished from the signal itself;
- difficulties in transmitting control signals;
- difficulties in pairing with a computer and other digital devices;
- encryption difficulties.
What is discrete
Discreteness is used in computing for packet data
A discrete signal is one that can take a certain number of values in a certain interval. These signals include the readings of a digital clock or devices, as well as texts in books.
Thanks to advances in digital technology, most electronic devices are now digital and work with DS. At the same time, physical signals in nature have an analog appearance. The conversion of the NS into a discrete form is performed by sampling it with the help of special devices (ADC). The inverse signal conversion is performed using a DAC.
The advantages of digital systems operating in DC are:
- high noise immunity and the ability to work communication channels with high noise;
- easy transfer of channel management commands;
- the possibility of digital signal processing;
- ease of classifying.
The possibility of discretization of a continuous signal with any desired accuracy (to increase the accuracy it is enough to reduce the step) is of fundamental importance from the point of view of computer science. A computer is a digital machine, that is, the internal representation of information in it is discrete. The discretization of the input signals (if it is continuous) allows us to make them suitable for discrete processing.
Differences between the two types of signals
All values of a discrete signal can be numbered by integers.
The main difference of the continuous signal from the DS is that it can have any value in the specified range, whereas the DS can only take certain values.
The disadvantages of systems that use DS include:
- the increase in bandwidth required for message transmission;
- a significant number of quantization levels and a high frequency are required to ensure accurate reproduction of the continuous signal when sampling;
- synchronization requirement;
- poor compatibility with existing analog systems.
Various processes can be described using continuous or discrete signals. A continuous signal can have any value from a certain range of values, whereas for a discrete signal its possible values are defined in advance. In many cases, when using digital information processing methods, it is useful to convert continuous signals to discrete ones.