How does the telephone spread sound?

Telephone is a communication technology that converts acoustic energy and electric energy and transmits language through electricity. The simplest way for two users to communicate is to connect two phones with a pair of wires.

A telephone has a receiver and a microphone. There is a magnetic ring in the microphone, which can convert people's sound waves into electromagnetic waves, then into electric waves, and then transmit them to the receiver at the other end through the line. There is also a similar magnetic ring in the receiver. After receiving it, it will reduce the radio waves to electromagnetic waves, and then reduce the electromagnetic waves to sound waves, so as to hear the other party's voice. ?

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Main categories:

1, wired telephone

The telephone has the function of converting the sound wave of the terminal into an electronic signal, transmitting it to a distant party through a telephone line, regenerating the electronic signal transmitted by the other party into voice (sound wave), making it talk, and sending a signal (dialing pulse) selectable from multiple parties to inform the other party of the calling sound.

A telephone consists of a transmitter that converts voice into current and sends it to a telephone line, a receiver that converts current sent by the other party into voice, a dial or button of the calling party, a ringtone that sends a call tone, and a line network that connects these to the telephone line to perform its functions. There is a small box filled with carbon particles in the transmitter, with a thin and hard aluminum alloy vibrating plate in front.

The vibrating plate vibrates according to the sound, vibrates the carbon particles, and the carbon particles conduct current. With the contact degree of particles, the resistance changes, resulting in voice current. After the receiver receives the voice current of the other party, it generates magnetic force on the coil caused by the voice current, vibrates the iron vibrating plate and makes sound.

2. Wireless telephone

Wireless loop cordless telephone, digital cordless telephone with telephone mother and daughter machine, analog cordless telephone, mobile phone, PHS (wireless telephone).

3. Smartphones

With the rapid development of IT technology, the processing capacity of embedded terminal equipment is getting stronger and stronger. At the beginning of this century, a telephone with personal digital assistant (PDA) appeared.

In addition to the complete fixed-line telephone function, smart phones usually have the functions of large-capacity business card management, incoming and outgoing call management, preventing telephone harassment (telephone firewall), enterprise group telephone business card management (internal business card), and many other functions to assist office work, such as scheduling, notes, calendars, calculators, etc.

Smart phones have Internet access and powerful multimedia functions. You can browse the Internet, play audio and video, and have the functions of e-books and electronic photo frames. At the same time, the functions of smart phones in supporting office, marketing and entertainment have been greatly enhanced. On the basis of subverting the traditional fixed telephone, more business functions and PDA functions are realized.

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