In a guided transmission medium, the signal travels in a fixed direction, also known as a wired vale

It is important to know that what we call electromagnetic wave propagation all depend on the medium, and the propagation of electromagnetic waves is carried out in the medium, and the propagation speed in different media depends only on the permeability [formula] and dielectric constant [formula] of the medium, regardless of thickness.

It can be compared to the speed at which a person travels has nothing to do with how big the ground is, but how rough it is.

The formula for the phase velocity of electromagnetic waves propagating in a medium [formula] has different values for different media. where [formula].

Vacuum permeability [formula], the permeability of air with respect to vacuum [formula].

Vacuum permittivity [formula], the permittivity of air relative to vacuum [formula].

Macroscopically, the propagation speed of electromagnetic waves in a medium depends only on the magnitude of the [formula], e.g. a medium of air can be approximated as a vacuum medium.

The phase velocity of the electromagnetic wave in air can be obtained as [formula], which is often referred to as the speed of light c

Commonly used wired communication media in computer networks: twisted pair, coaxial cable and optical fiber, divided into: twisted pair, coaxial cable and optical fiber of wired medium, as well as microwave and satellite of wireless channel.

Wireless transmission media commonly used in computer networks: microwave, infrared, laser or satellite.

A wired transmission medium is the part of the physical connection between two communication devices that transmits signals from one to the other.

Wireless transmission medium refers to a technology that transmits between two communication devices through space without using any physical connection.

He said that entry is like a signal, propagating in a fixed direction, also known as the stuffing world, and this statement is completely correct, and he is right.

Let the color be fixed, and the ship also has a limited value.

This statement is true. The signal is only transmitted along the set medium.

It seems that the transmission boundary of the second is propagating in a fixed direction, also known as a finite medium, which can also be said to be true, because he is fixed after all.

In the island transmission medium, the signal travels in a fixed direction, also known as finite value, and he is correct in this statement.

This should be a concept in the book, and you will have it when you put this sentence on the browser.

The transmission medium refers to the medium through which the signal is transmitted between () and the receiving device.

a.Sources of information.

b.Send device files.

c.**Device.

d.Gateway. Correct answer: B