Meaning radio method, country study. A Study on Radio Law is an academic monograph that makes an in-depth discussion on the issues related to the formulation of radio law in China. This book is clear in logic, detailed in content and meaningful in words. It is a leader in the field of radio law research, effectively filling the gap and suitable for law students and scholars to read and study.
radio refers to electromagnetic waves propagating in all free spaces (including air and vacuum), which is a limited frequency band. The upper limit frequency is 3THz, and the lower limit frequency is not uniform. In various radio frequency specifications, the common ones are 3 kHz ~ 3 THz (specified by ITU-ITU), 9KHz~3THz and 1KHz~3THz.
The invention of radio
In p>1895, Italian Marconi (
Guglielmo Marchese
Marconi, 1874-1937) successfully carried out the experiment of transmitting signals by radio waves, and went to Britain to apply for a patent the following year.
in 1897, he founded Wireless Telegraph &. Signal Co., Ltd. (renamed Marconi's Wireless Telegraph Co., Ltd. in 19) established radio communication between Britain and France across the English Channel in 1899.
In December p>191, the antenna was towed by a kite in Canada, and the wireless telegraph from the other side of the Atlantic was successfully received. The news of this successful experiment caused a sensation in the world. Since then, many countries' military fortresses and seaports have been equipped with radio communication equipment, which has played an important role in keeping contact between ships sailing in the ocean and the land, ensuring maritime safety and military communication.