The differences between digital signals and analog signals are: different amplitude changes, different signal transmission methods, and different confidentiality.

1. Different amplitude changes

Digital signals refer to amplitude values ??that are discrete, and the amplitude representation is limited to a limited number of values. Analog signals refer to amplitude values ??that are continuous.

2. Different signal transmission methods

Digital signals are transmitted through a digital stream composed of digital strings of 0 and 1. An analog signal is a television signal represented by an analog voltage or current.

3. Different confidentiality

Digital signals have stronger confidentiality. The voice signal can be encrypted first, then transmitted, and then decrypted at the receiving end and then transformed back into an analog signal. Microwave communications and wired open-wire communications with analog signals are easily eavesdropped. As long as the analog signal is received, the communication content is easily obtained.

Advantages and Disadvantages of Digital Signals and Analog Signals

Digital signals improve anti-interference capabilities. Digital signals will be mixed with noise during the transmission process. The threshold voltage (called the threshold) formed by the electronic circuit can be used to measure the input signal voltage. Only when a certain voltage amplitude is reached, the circuit will have an output value and automatically generate a neat Impulse (called shaping or regeneration). When the smaller noise voltage arrives, it is filtered out because it is lower than the threshold and will not cause circuit action.

The disadvantage of digital signals is that they occupy a wider frequency band. Because the line transmits pulse signals, transmitting one channel of digital voice information requires a bandwidth of 20-64kHz, while an analog voice channel only occupies a 4kHz bandwidth, that is, one channel The PCM signal occupies several analog voice channels.

The advantages of analog signals are that they are intuitive and easy to implement, but they have two major disadvantages. Analog signals, especially microwave communications and open-wire communications, are easily eavesdropped. As long as the analog signal is received, the communication content is easily obtained. During the transmission process of electrical signals along the line, they will be interfered by various noises from the outside and within the communication system. After the noise and signals are mixed, it is difficult to separate, thus causing the communication quality to deteriorate. The longer the line, the more noise accumulates.