The act of sending information from one place, person, or organization to another is known as communication. A sender, a message, and a recipient are all part of every communication. This may sound simple, but communication is actually a very complex subject. The transmission of the message from sender to recipient can be affected by a huge range of things. These factors include our emotions, cultural context, communication medium, and even geographic location. The complexity is why good communication skills are considered so desirable by employers around the world: accurate, effective and unambiguous communication is actually extremely hard. Modulation is the addition of information to an electrical or optical carrier signal in order to turn data into radio waves. A carrier signal has a waveform that is consistent in height (amplitude) and frequency. Information can be added to the carrier by varying its amplitude, frequency, phase.
Types of modulation
- Amplitude modulation (AM) - The height(the power or
intensity) of the signal carrier is altered to reflect the data being added to
the signal.
- Frequency modulation (FM) - in which the frequency of the carrier waveform is varied to reflect the frequency of the data.
- Phase modulation (PM) - in which the phase of the carrier waveform is varied to reflect changes in the frequency of the data. In PM, the frequency is unchanged while the phase is changed relative to the base carrier frequency. It is similar to FM.
- Polarization modulation is a technique for reflecting data by changing the angle of rotation of an optical carrier signal.
- Pulse-code modulation - An analog signal is sampled to
generate a data stream that is used to modulate a digital carrier signal.
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| Modulation Types |
Why modulation
- The sender's baseband signals aren't capable of being transferred directly. The message signal's power should be raised to allow it to reach longer distances. The most important requirement of modulation is to increase the signal's strength without changing the carrier signal's properties.
- In communication systems, modulation has eliminated the need for wires. It's because modulation is extensively utilized to send signals at a higher rate from one site to another. As a result, the modulation method has aided in the advancement of wireless communication systems.
- Modulation and its various variants prevent extraneous signals from interfering with the message signal. It's because a person delivering a message signal over the phone won't be able to distinguish between them. As a result, they'll get in each other's way. The mixing of the signals can be avoided by utilizing carrier signals with a high frequency. As a result, modulation guarantees that the signals received by the receiver are flawless.
- Signals with a frequency range of 20 Hz to 20 kHz can only travel a short distance. The length of the antenna used to convey the message signal should be a quarter wavelength of the employed frequency. As a result, modulation is required to boost the communication signal's frequency and strength so that it can reach the receiver.
The process of encoding information in a transmitted signal is known as modulation, whereas the process of retrieving information from the signal is known as demodulation. Multiplexing, also known as time-division multiplexing, merges the streams into a single carrier, for example, by encoding a fixed-duration segment of one, then of the next, cycling through all the channels before returning to the first (TDM). Many factors influence how faithfully the extracted information replicates the original input information. Electromagnetic interference can degrade signals and make the original signal impossible to extract. Demodulators typically include multiple stages of amplification and filtering in order to eliminate interference. Sometimes a carrier signal can carry more than one modulating information stream.
Frequency-division multiplexing (FDM) is another type of multiplexing in which several carriers of various frequencies are utilized on the same media.
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