When humanity entered the era of wireless communication, our lives have undergone tremendous changes. Wireless communication has some inherent advantages. We often say that an analog signal represents a continuously changing electromagnetic wave. A digital signal represents a sequence of voltage pulses. Computer local sharing is a typical digital data transmission through digital signals. The biggest problem with communication signals is noise, because noise affects digital bits. Let's take a look at its specific principles today.
In 1901, Guglielmo. Marconi transmitted long-wave radio signals from Cornwall (Cornwall, southwest England) across the Atlantic to Newfoundland (Newfoundland, Canada) 3,200 km away, and humans entered the era of wireless communications. For more than 100 years, the development of wireless technology has brought radio, television, mobile phones and communications satellites to humans. In the past 20 years, what has made people feel deeply is mobile communication. The mobile phone has almost become an organ of people, and it is convenient to access the Internet.
Wireless communication has some inherent advantages: low input costs, large expansion flexibility, and obstacles across space. We speculate that the following will be the future trend:
l Mains-powered equipment (television, stereo, etc.) uses high-speed short-range wireless such as UWB.
l Battery-powered equipment (energy meter, bicycle, etc.) will use micro-power wireless.
l Handheld devices (mobile phones, tablets, etc.) continue to use 4G/5G mobile communication technology.
The bolder speculation is that with the breakthrough of biometrics, large-capacity energy storage and flexible screen materials, display and communication will be everywhere, mobile phones will disappear, and payments can be fingerprinted.
It's time for us to uncover the mystery of wireless communications, understand the principles, and get in touch with a micropower wireless communication that is coming.
First, the principle of wireless communicationIn communication systems, we need to understand the relationship between analog and digital: an analog signal is a continuously changing electromagnetic wave, and a digital signal is a sequence of voltage pulses. To see an example, the following picture is selected from the classic textbook "Wireless Communication and Network (Second Edition)". Telephone communication is typical analog data (sound wave) transmitted by analog signal; home broadband dial-up is typical digital data (computer only Can handle digital signals) transmitted by analog signals (modulated by "cat"), while analog signals can also be converted to digital signals (demodulation by "cat"); computer local sharing is typical of digital data through digital signals transmission.
The first "enemy" of the communication signal is noise, as shown in the figure below, the noise affects the digital bits, enough to change 1 to 0, or 0 to 1.
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