The modulating process plays a key role in communication systems.
In addition to the primary role of modulating as the Frequency Conversion Operation, modulating has other purposes as follows:
Embedding to customize the location of the frequencies
Modulation for Frequency Location assignment
The embedding process here determines the location of the carrier signal in the frequency spectrum assigned to it, and this assignment is very important in areas where there is more than one type of communication system.
Embedding to change the package width
Modulation for Bandwidth Alteration
The width of the original signal packet can be changed to a higher or lower value depending on the type of modulation used
Modulation for increase Efficiency of Radiation
The process of electromagnetic radiation is efficient when the antenna dimensions are about 10% of the wavelength λ, but for a large number of signals, especially audio signals, have frequency components of 100 Hertz or less, and this requires antennas with a length of λ = 300 km if the radiation is These signals are direct and this is not practically possible, but by using the modulation process, the antenna length can reach 300 m with a displacement of this frequency to 1 MHZ, for example, and the speech is relative ... as C = f×λ, and thus we can design efficient antennas with modulation High and with suitable dimensions at high frequencies.
Modulation to reduce noise and interference
When people send the baseband signal as it is to a receiver for example from a mobile phone to another phone, there will be thousands of people in the city using their mobile phones and there is no way to distinguish between these signals, they will interfere with each other causing a lot of noise In the system and very poor output, by using a high-frequency carrier and allocating a range of frequencies to each message, there is no mixing between the signals and the received signals are completely perfect ~~~ And as we know that it is impossible to remove noise from communication systems as it is generated implicitly in these systems while The interference between these systems can be removed ~ There are certain types of modulation to reduce noise and interference, but all this is at the expense of the transmitter packet width (frequency range).
Modulation to overcome Equipment Limitations
The design of a particular system is limited by the available devices and the performance of these devices depends on the frequencies used, the modulation can transmit the signal to that part of the frequency spectrum at which the device selections are the least possible, or because the design at this part of the spectrum is easier
Therefore, the modulation process is usually present in the transmitters and receivers.
Please check the : Introduction to Signals Modulation Part 1
Thank you.
