The difference between analog electronics and digital electronics

The difference between analog electronics and digital electronics:

Digital circuit is a circuit that processes logic level signals. It uses digital signals to complete arithmetic operations on digital quantities and Logic operation circuit. On the whole, digital circuits are divided into two categories: combinational logic circuits and sequential logic circuits.

Digital circuits are developed on the basis of analog circuits. Digital circuits are based on analog circuits. Their basis is current and voltage, but they are essentially different.

The current and voltage of an analog circuit are constant within a cycle, while the current and voltage of a digital circuit are pulsating.

Analog circuits and digital circuits are also carriers of signal changes. Analog circuits amplify and reduce signals in the circuit through the amplification characteristics of components, while digital circuits transmit signals. Operation is achieved through switching characteristics.

In analog circuits, the changes in voltage, current, frequency, and period are mutually restricted, while in digital circuits, the changes in voltage, current, frequency, and period are discrete.

Analog circuits can work under high current and high voltage, while digital circuits only work under low voltage and low current consumption to complete or generate stable control signals.

The analog circuit supplies power to the digital circuit and completes the execution of the actuator.

In analog circuits and digital circuits, signals are expressed differently. Operations that can be performed on analog signals, such as amplification, filtering, limiting, etc., can also be performed on digital signals. In fact, all digital circuits are fundamentally analog circuits, and their basic electrical principles are the same as analog circuits. Complementary metal oxide semiconductor is composed of two analog metal oxide field effect transistors. Its symmetrical and complementary structure allows it to handle high and low digital logic levels. However, digital circuits are designed to process digital signals, and if any analog signal is forcibly introduced without additional processing, quantization noise may result.

The first device invented and mass-produced in the history of electronics was analog. Later, with the development of microelectronics, the cost of digital technology was greatly reduced, and the requirements of computers for digital signals made digital methods feasible and cost-effective in fields such as human-computer interaction.

In analog circuits, since the signal almost completely expresses the real signal in the form of voltage or current in proportion, the analog circuit is more sensitive to the impact of noise than the digital circuit, and small deviations in the signal will appear quite significant. , causing information loss. In contrast, digital circuits only depend on high and low levels. If errors in information transmission are to occur, the signal deviation must be at least half of the high level (the specific size varies according to different circuit specifications). Therefore, digital circuits that quantify information are more resistant to noise than analog circuits. As long as the deviation is not greater than a certain specified value, the information will not be lost. In digital circuits, noise can be reduced at each logic gate.

There are several factors that will affect the accuracy of the signal, the most important of which are the noise in the original signal and the noise mixed in during signal processing. The resolution of analog signals is limited by physical limitations of the device, such as shot noise. In digital electronics, the resolution of digital signals can be improved by increasing the number of bits in the signal (for example, an analog-to-digital converter with 8-bit resolution can divide its range into 8 segments, each of which is converted as a minimum division). The number of conversion bits is a key parameter of an analog-to-digital converter. An analog-to-digital converter converts an analog signal into a digital signal so that the original signal can be represented as a binary number for processing by digital circuits. Applications using this converter include digital thermometers and data acquisition equipment such as recorders. On the contrary, a digital-to-analog converter is used to restore digital signals to analog signals. It can read in a series of binary signals and output them as analog signals in the form of voltage values ​​after conversion. Digital-to-analog converters are common in many op amp gain control systems.

The design of analog circuits is usually more difficult than digital circuits and requires higher levels of designers. This is one of the reasons why digital circuit systems are more popular than analog circuit systems. Analog circuits generally require more manual calculations, and their design process is less automated than digital circuits. However, for digital electronic devices to be used in the real physical world, they must have an analog interface, because most actual signals in nature are analog. For example, all digital radio signal receivers have an analog preamplifier to perform the first step of signal reception.

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