The refractive index of ionosphere is
$ \mu = \sqrt{ 1 - \frac{ 80.6 \, N }{ f^2 }} $
where N is free electron density typically equal to $ 10^{11} \, m^{ - 3 } $ and v is frequency of waves in kHz.
So, we have $ \mu < 1 $
Hence, refractive index of ionosphere is less than one.
A system that describes the information exchange between two points is called the communication system. The transmission and reception process of information is called communication. The major elements of communication are such as:
The Transmitter of information
Channel or medium of communication
The Receiver of information
Examples Of Communication Systems:
The following are the examples of communication systems:
Internet
Public Switched Telephone network
Intranet and Extranet
Television
Types Of Communication Systems:
Turning on Signal specification or technology, the communication system is categorized as follows:
Analog technology communicates data as electronic signals of differing frequencies or amplitude. For instance Broadcast and telephone transmission.
In Digital technology, the data are created and processed in two states: High (represented as 1) and Low (represented as 0). Also this technology stores and transmits data in the form of 1's and 0's.