The first person to develop a mobile phone was Dr. Cooper in the United States. Due to constraints such as battery capacity limitations at the time, analog modulation technology requiring huge antennas, and the development of integrated circuits, this kind of mobile phone had a boxy appearance and could only be moved but not considered portable. Many people call this kind of mobile phone "Brick" or "Black King Kong".
This kind of mobile phone has many standards, such as NMT, AMPS, and TACS. However, it basically uses frequency division multiplexing for voice communication. The reception effect is unstable, and the confidentiality is insufficient. The wireless bandwidth is Underutilized. This kind of mobile phone is similar to a simple duplex radio. The call is locked to a certain frequency, so using the adjustable frequency radio, the call can be eavesdropped.
In 1958, Soviet engineer Leonid Kupriyanovich invented the ЛК-1 mobile phone. In 1973, American Motorola engineer Martin Cooper invented the world's first mobile phone. Commercial cell phones. So far it has developed into the 4G era.
Extended information:
Several common types of mobile phones:
Clamshell type
The main display must be visible only when the cover is opened or buttons, and has only one screen, the phone is called a single-screen flip phone. Dual-screen flip phones have also been launched on the market, that is, there is another secondary display screen on the flip cover. This screen is usually not large and can generally display functions such as time, signal, battery, and caller ID.
Subbar type
Subbar type mobile phone means that the mobile phone screen and buttons are on the same plane, and the mobile phone does not have a flip cover. It is what we often call a candy bar phone. The main feature of upright mobile phones is that you can directly see the content displayed on the screen.
Sliding type
Sliding type mobile phone mainly means that the entire body of the mobile phone must be seen by pulling it out. On some models, you can see the keys by sliding the lower cover; on others, you can see the keyboard by pulling up the screen part. To a certain extent, slider phones are an extension and innovation of flip phones.
Watch-style mobile phones
Watch-style mobile phones mostly had simple small functions in the early days. However, as they develop to the smartphone stage, watch-style mobile phones have more complete functions, such as Samsung's Galaxy Gear V700. The earliest domestic mobile phone watch is YAMi.
The rotating type
It is similar to the sliding type. The most important thing is that you can see the keyboard after rotating 180°.
Side sliding type
It is a variant of the sliding type, which is operated by pushing the screen to the left or right to expose the keyboard. For large-screen touch-operated smartphones, side sliding greatly speeds up typing, enhances and optimizes the experience of playing games, and makes such smartphones more popular. Such as Nokia N97 and Motorola Milestone.
Baidu Encyclopedia-Mobile Phone (Mobile Phone)