What are the transmission technologies commonly used in remote communications in computer network systems?

The transmission technology commonly used in remote communication in computer network systems is "frequency band transmission". There are three basic methods of data transmission: baseband transmission, frequency band transmission, and digital data transmission; among them, frequency band transmission is suitable for long-distance transmission. Frequency band transmission is a transmission method that uses a modulator to perform frequency exchange of transmission signals. Long-distance communication in computer networks often relies on telephone systems, and frequency band transmission is usually used; the conversion of baseband signals and frequency band signals is performed by modulation and demodulation. Technically done.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

The transmission technology commonly used in remote communication in computer network systems is "frequency band transmission".

There are three basic methods of data transmission: baseband transmission, frequency band transmission, and digital data transmission. Among them, frequency band transmission is suitable for long-distance transmission, and baseband transmission is suitable for data transmission on a parallel bus in a computer.

Frequency band transmission

Frequency band transmission is a transmission method in which the signal is modulated and transmitted to the terminal and then demodulated again. That is, the digital signal (binary electrical signal) is modulated and converted into an analog signal (audio signal) that can be transmitted on a public telephone line. After being transmitted to the receiving end through the transmission medium, the modem then demodulates and converts the audio signal into the original Binary electrical signal. Frequency band transmission requires separate modems at the sending end and receiving end. This transmission method overcomes the shortcomings of many long-distance telephone lines that cannot directly transmit baseband signals, and can realize multiplexing functions.

Frequency band transmission is a transmission method that uses a modulator to frequency exchange the transmission signal. The purpose of signal modulation is to better adapt to the frequency characteristics of the signal transmission channel. The transmission signal can also overcome the baseband after modulation processing. It eliminates the shortcomings of too wide transmission bandwidth and improves line utilization, killing two birds with one stone. However, the modulated signal needs to be demodulated and restored at the receiving end, so the transmitting and receiving end of the transmission requires special signal frequency conversion equipment, and the cost of transmission equipment increases accordingly. Most long-distance communication channels are analog channels. For example, traditional telephones (telephone channels) are only suitable for transmitting analog signals in the audio range (300-3400Hz), and are not suitable for direct transmission of digital signals with a wide frequency band but energy concentrated in low frequency bands. baseband signal.

Frequency band transmission is to first convert (modulate) the baseband signal into an analog signal with a higher frequency range (called a frequency band signal) that is convenient for transmission in the analog channel, and then transmit this frequency band signal in the analog channel medium transmission. When using the frequency band transmission method, modems are required to be installed at both the sending and receiving ends. The use of frequency band transmission not only solves the problem that digital signals can be transmitted using the telephone system, but also enables multiplexing to improve the utilization of transmission channels.

Long-distance communication in computer networks often relies on telephone systems, usually using frequency band transmission.

The conversion of baseband signals and frequency band signals is completed by modulation and demodulation technology.

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