As the name suggests, the d630 demodulator is the modulation and demodulation of the signal. That is, the digital signal is converted into an analog signal transmitted on the telephone line; demodulation is to convert the analog signal into a digital signal. Synonymous with a modem. The telephone line we use transmits analog signals, and the digital signals are transmitted between PCs. So when you want to connect your computer to the Internet via a telephone line, you must use a modem to "translate" two different signals.
After connecting to the Internet, when the PC sends information to the Internet, because the telephone line transmits an analog signal, it is necessary to use a modem to "translate" the digital signal into an analog signal before it can be transmitted to the Internet. This process is called "modulation." ". When a PC obtains information from the Internet, since the information transmitted from the Internet through the telephone line is an analog signal, the PC wants to understand them, and must also use the modem to "translate". This process is called "demodulation." . In general, it is called "modulation and demodulation.
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