Modulation

What is amplitude modulation? 

It is a flexible device used for electronic communication, usually through a radio transmitter. In amplitude modulation, a wave’s amplitude (signal strength) varies in proportion to that of a signal, such as a sound signal. Amplitude modulation is the process by which a wave signal is transmitted by changing the signal size. It is commonly called AM and is often used to transmit a piece of information through a radio transmitter. Amplitude modulation is widely used in the form of electronic communication.

Amplitude modulation is defined as a kind of modulation in which the carrier wave’s amplitude varies in proportion to the modulating data or signal.

There is a fluctuation in the amplitude of the carrier when amplitude modulation is utilised as a method. The carrier’s amplitude is affected by the voltage or power level of the transmitting information. The carrier amplitude in AM does not change. On the other hand, the modulating data takes the shape of signal components with frequencies that are either greater or lower than the carrier frequency. The signal components are considered sidebands, and the sideband power causes the signal’s total amplitude to vary.

Need for Amplitude Modulation

Signal Strength

The sender’s baseband signals are unable to be sent directly. The communication signal’s power should be enhanced for it to go further. Modulation becomes crucial at this point. The most important need for modulation is to increase the signal’s power while preserving the carrier signal’s properties.

Wireless Communication

In communication systems, modulation has eliminated the need for cables. Modulation is extensively utilised 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.

Multiplexing

Multiplexing is a technique for concurrently transmitting two or more signals over the same communication channel. Only modulation enables this. Multiplexing is a technique that allows many signals to use the same channel. As a result, many TV stations can use the same frequency range without interfering with one another, or various frequency transmissions can be broadcast simultaneously.

Reception Quality

The influence of noise is significantly decreased by frequency modulation (FM) and digital communication methods such as PCM. This enhances reception quality.

Pros of Modulation

• Amplitude Modulation is less difficult to set up.
• Demodulation may be accomplished with a few simple components and a circuit.
• The AM receiver is relatively inexpensive.

Uses of Modulation

• The inter-conversion of data and signals from one form to another is one of the most prevalent applications of various forms of modulation.
• The digital signals are sent over analogue baseband using digital modulation.
• Analog Modulation is a technique for transferring low-bandwidth transmissions, such as TV or radio, to a higher-bandwidth signal.
• FDM, or Frequency Division Multiplexing, commonly uses modern modulation techniques.

Types of Modulation

Amplitude Modulation: If the amplitude of the base signal varies or modulates due to superimposing the base signal with a carrier signal of a different amplitude but the same frequency, it is said to be amplitude modulation.

Phase Modulation: When a carrier signal is superimposed on a base signal, the phase of the base signal changes.

Frequency Modulation: It is defined as the modification or modulation of the frequencies of the base signal caused by superimposing it with a carrier signal of a different frequency but the same amplitude.

Analogue Modulation: The process of transmitting an analogue baseband (low frequency) signal, such as an audio or TV broadcast, over a higher frequency signal, such as a radio frequency band is known as analogue modulation.

Pulse Modulation: Where the signal is sent in pulses. It has the capability of transmitting analogue data. Continuous signals are sampled at periodic intervals in pulse modulation.

Digital Modulation: The technique of embedding a digital data signal into the transmitted signal’s amplitude, phase, or frequency is known as digital modulation. The encoding technique impacts the transmitted signal’s bandwidth and resistance to channel degradation.

Conclusion

Today, amplitude modulation, AM, is used for audio broadcasting in long and medium wavebands and two-way radio communication via aircraft high frequency. However, as there are now more efficient and straightforward ways to change the signal, its use is declining, though it will still be many years before it is used. AM has the advantages of simplicity, although not the most efficient method of use, both in terms of space value or spectrum utilisation and how it uses energy transfer. This is why it is no longer widely used these days in broadcasting and communication of two people on the radio. Even the wavelengths of long, medium and short waves will eventually change because the amplitude change is much lower in noise levels than other alternatives. Its simplicity and versatility mean that it will be difficult to replace quickly and will be used for many years to come.