Analog system and digital system

Electronic circuits are made up of a digital system and an analog system .

The concepts of analog system and digital system refer to the two categories in which electronic circuits are classified. Below we present the differences between these two systems, definitions, concepts and examples so that you can share with your family and friends.

Analog System and Digital System

A digital system  is a combination of devices designed to manipulate physical quantities or information that is represented in digital form, that is, it can only take discrete values.

An analog system is one whose signals can admit infinite values ​​that can vary continuously, the data that are part of nature is of analog origin, temperature, distance, sound, voltage, images, etc.

The main difference between a digital system and an analog system is that the former is more precise and the information can be stored more efficiently and in greater quantity than in an analog system.

A digital system is any device for the generation, transmission, processing or storage of digital signals, also a digital system is a combination of devices designed to manipulate physical quantities or information that are represented in digital form, that is, they can only take discrete values .

Most of the time these devices are electronic, but they can be mechanical, magnetic or pneumatic. Boolean algebra is used as a tool for the analysis and synthesis of binary digital systems. Digital systems can be of 2 types:

• Combinational Digital Systems: These are those in which the output of the system only depends on the present input, therefore it does not need memory modules, since the output does not depend on previous inputs.
• Sequential Digital Systems: The output depends on the current input and the previous inputs, this class of systems need memory elements that collect the information of the past history of the system.

For the implementation of digital circuits logic gates (AND, OR, NOT) and transistors are used. These gates follow the behavior of some Boolean functions.

A System is Analog when when the signal magnitudes are represented by continuous variables, this is analogous to the magnitudes that give rise to the generation of this signal. An analog system contains devices that manipulate physical quantities represented in analog form, in a system of this type, the quantities vary over a continuous range of values. Thus, an analog quantity is one that takes continuous values.

Most things that can be measured quantitatively appear in nature in analog form, an example of that is temperature.

Analog signal

An Analog Signal is a voltage or current that varies smoothly and continuously, a sine wave, it is an analog signal of a single frequency, the voltages of the voice and the video are analog signals that vary according to the sound or variations of the light that correspond to the information that is being transmitted.

Digital Signal

Digital signals, in contrast to analog, do not vary continuously, but change in discrete steps or increments, and most digital signals use binary or two-state codes.

Advantages of Digital Circuits 

There are several reasons for giving preference to digital circuits over analog circuits.

Reproducibility of results:

Any digital circuit will always reproduce exactly the same results, the outputs of an analog circuit vary with temperature.

Ease of design:

Digital design is logical, no special mathematical skills are needed, and the behavior of small logic circuits can be visualized mentally without having any special idea about the operation of capacitors, transistors, or other devices that require calculation to regulate themselves.

Flexibility and functionality:

Once a problem has been reduced in digital form, it can be solved using a set of logical steps in space and time.

Programmability:

You are probably already familiar with digital computers and the ease with which you can design, write, and debug programs for them.

Speed:

Today’s digital devices are very fast, which means that one device can produce more results per second.

Economy:

Digital circuits can provide a lot of functionality in a small space, circuits that are used repetitively can be mass-manufactured at very low cost.

Constant technological advance:

When designing a digital system, it is almost always known that there will be a faster, cheaper, or in any case, a superior technology for the same case for a short time.

Advantages of digital signal processing over analog

There are many reasons why digital processing of an analog signal may be preferable to processing the signal directly in the analog domain . First, a programmable digital system allows flexibility in reconfiguring digital signal processing operations without more than changing the program. Reconfiguration of an analog system usually involves redesign of the hardware, followed by testing and verification to see that it operates correctly.

Consideration of accuracy also plays an important role when choosing a signal processor format. Tolerances in analog circuit components make it extremely difficult for the system designer to control the accuracy of an analog signal processing system.

Instead, a digital system allows better control of precision requirements. The digital processing method also enables the implementation of more sophisticated signal processing algorithms, it is generally very difficult to perform precise mathematical operations on signals in analog format.

Advantages and disadvantages of analog systems

We can summarize that the advantages are:

• Instantaneity
• Economy
• Fidelity

And the disadvantages are:

• Noise
• Degradation
• Technical difficulties

Advantages and disadvantages of digital systems

We summarize the advantages :

• Efficiency
• Less size
• Design
• Precision
• Stability

While the disadvantages would be:

• Disturbance
• Bandwidth
• Conversion

Examples of analog systems that have gone digital

Photography:

The increase in the density of digital memory microcircuits has allowed the development of digital cameras that record an image as a 640 x 480 matrix, this large amount of data can be compressed in a format called JPEG and reduced to such a small size as the equivalent of 5% of its original storage size depending on the amount of detail in the image.

Video Recordings: 

A versatile digital multi-use disc, DVD, stores video in a highly compressed digital format called MPEG-2, this standard encodes a small fraction of individual frames of video in a compressed format such as JPEG.

Audio Recordings: 

The perfect example is the full capacity CD for 73 minutes, containing up to six billion bits of information.

Car Carburetors: 

Today’s automobiles are controlled by embedded microprocessors. Various electronic and electromechanical sensors convert machine conditions into numbers that the microprocessor can examine to determine how to control the flow of gasoline and oxygen to the engine. The microprocessor output is a time-varying series of numbers that activates electromechanical transducers that in turn control the machine.

The telephone system:

Today many businesses and offices contain combined digital voice services with digital traffic over a single internet protocol data network.

Traffic lights: 

Electromechanical timers were used to control the traffic lights that enabled the green light for each one. Microprocessors are now in use and can control traffic lights to maximize traffic flow.

Cinematic Effects:

Nowadays, the special effects of ships, insects or other scenes are completely synthesized using digital computers.