10:00 to 18:00 (Weekdays)
10:00 to 18:00 (Weekdays)
Modulation of a signal is a widely used phenomenon in telecommunication and electronics.
Going by the definition the Modulation, is a technique for impressing information (voice, music, picture, or data) on a radio-frequency carrier wave by varying one or more characteristics of the wave by the intelligence signal or the signal carrying the information.
It is typically the process of encoding information from a message source in a suitable way for transmission.
There are many types of Modulation, each designed to alter a specific characteristic of the carrier wave. The most commonly altered characteristics are amplitude, frequency, phase, pulse sequence, and pulse duration.
The carrier wave, usually a high-frequency wave used to carry the information wave, as mentioned earlier, can travel up to a longer distance without getting affected by external disturbances, thus called so.
So altogether, this process involves:
However, the question arises as to why do we need modulation in the first place? Can’t we send the message signal over the distance while receiving it at the other end?
Wavelength (λ) = Speed of Light (c) / Frequency (ϑ)
Speech frequencies range from 20 Hz to 20 kHz. Suppose a frequency of 18 kHz and it is transmitted out to a receiver through a channel of free space. The size of the antenna in terms of its length can vaguely be obtained as:
Length(L) = Wavelength (λ) = Speed of Light (c) / Frequency (ϑ)
= 3 * 10^8 / 18 * 10^8 = 16.66 km
With the low frequency and high wavelengths of the baseband signals, the size (length) of the antennas is not practical (in kilometres), like in this case.
When we use the high-frequency carrier signal to transmit the baseband signal, the frequency of the overall modulated or the broadcasted signal increases, this makes its wavelength lower, resulting in practical and feasible sizes(lengths) of the antennas.
Thus, the technique of Modulation is used to increase the reach of the signals. It’s used everywhere, be it wired /wireless communication or cellular / WI-FI network. Modulation makes the signal usable and maintains its quality.
Author: Sayalee Kahandal for ThinkRobotics
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