The difference in application between analog and digital
Analog circuits are circuits that process analog signals; digital circuits are circuits that process digital signals. The analog signal is a function of time and is a continuously varying quantity, while the digital signal is a discrete quantity. All electronic systems are ultimately specific In the process of signal processing, the signal acquisition and recovery stages are all analog signals, and only the middle part is digital processing. Specifically, the analog circuit mainly processes analog signals and does not change with time. Signals that are continuous in domain and value domain, such as speech signals. On the contrary, digital signals are changing. Digital signal processing includes signal sampling, signal quantization, and signal encoding.
If you want to transmit a sound that changes from small to loud from a distance, use amplitude modulation and analog signal to transmit (the corresponding analog circuit should be used), then the amplitude of the signal during the transmission will become larger and larger, because it It is using the amplitude characteristics of the electrical signal to simulate the strength and weakness of the sound. However, if digital signal transmission is used, a kind of encoding is used, and each level of sound size corresponds to a kind of encoding. At the sound input end, every time a sample is taken, The corresponding code is transmitted. It can be seen that no matter how many levels of the sound are divided, no matter how high the sampling frequency is, for the original sound, there is always a loss in this way. But this loss can be compensated by increasing the sampling frequency. In theory, the sampling frequency is greater than twice the frequency of the original signal and it can be completely restored
The connection between analog and digital in application
The analog circuit is to supply power to the digital circuit and complete the execution of the actuator. In the analog circuit and the digital circuit, the expression of the signal is different. The operations that can be performed on the analog signal, such as amplification, filtering, limiting, etc. It can operate 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 semiconductors are composed of two simulated metal oxide field effects. The tube is composed of symmetrical and complementary structure, so that it can handle high and low digital logic levels. However, the design goal of digital circuits is to process digital signals. If any analog signal is forcibly introduced without additional processing, it may be possible Cause quantization noise.
A function that represents the value of a signal under a set of discrete times is called a discrete time signal. Because the most commonly encountered discrete time signal is an analog signal that is sampled at uniform (and sometimes non-uniform) intervals in time. And "discrete "Time" and "digital" are also often used to describe the same signal. Some theories of discrete time signals also apply to digital signals.