Amplitude modulation is performed when we transmit data or information over the wires. Typically, amplitude modulation is designed to help the receiving machine identify data in the original quality. When we send any data via cable or using a wireless connection, it always carries an analogue signal even if it is a digital connection. In the modified signal waveform amplitude, the amplitude gets changed, i.e. it can be low or high sometimes. Therefore, when we transmit a digital signal, the digital data ‘1’ and digital data ‘0’ are used to represent high amplitude and low amplitude, respectively.

Applications of Amplitude Modulation

There are numerous applications of amplitude modulation, some of which are listed below:

• The use of radio waves can be made for transmitting data and information in amplitude modulation.
• Communication systems such as electronic analogue are implemented using amplitude modulation.
• In ancient times, there was a need to transmit voice through radio. Hence amplitude modulation was quite helpful.
• The pixels on the television screen were controlled using amplitude modulation in olden times.
• It is still used in two-way communication radio systems, modems of computers, citizen band radio, etc.
• For controlling the audio level in an analogue mixer, amplitude modulation can be quite useful.
• Now, since it is used in two-way communication radio systems, this can be implemented in aircraft too for voice communication.
• In the olden era, the morse code was transmitted with the help of amplitude modulation only.
• This use of amplitude modulation was also used by navy dispatch and the police radio systems.

Advantages and Disadvantages of Amplitude Modulation

Some pros and cons of amplitude modulation are listed below:

Advantages:

• The low cost of the overall components in the circuit is only possible because of amplitude modulation.
• The circuit modified using amplitude modulation is also not very complex to operate.
• The amplitude modulation is not only limited to audio signals. The carrier wave can also be enhanced in video signals.
• Now, if any signal is modulated, there is a need to demodulate the signal for the receiver to listen to original audio quality, hence this process is also easy by using a few components in the circuit.

Disadvantages:

• In the whole creation of amplitude modulation, there is some noise creation leading to noise pollution.
• Electromagnetic interference can also be considered as one of the cons of amplitude modulation.
• Very little efficiency can sometimes lead to the wastage of resources used for enhancing signal amplitude.
• Power loss or use of inefficiency of power consumption.

Radio/Wireless Concept in Amplitude Modulation

Here, the voltage level or power level in amplitude modulation of the information signal alters the amplitude of the carrier equally. Without conversion, the AM network carrier is made to broadcast itself. Now, when a sine wave signal is used, the network carrier amplitude falls and rises in parallel. The frequency of the network carrier remains the same during AM. It is used in radio communication widely. Another type of AM, known as quadrature amplitude modulation (QAM), is also broadly used to transmit digital data using cable in modems.

Broadband Interface Concept in Amplitude Modulation

Here, the voltage level of the signal to be transmitted in amplitude modulation changes the amplitude of the carrier by measurement. Without conversion, the AM network carrier is made to broadcast itself. Now, when a sine wave signal is used, the network carrier’s amplitude falls and rises in parallel. The frequency of the network carrier remains the same during AM. Analogue amplitude modulation is broadly used in radio. 

Amplitude Demodulation

Module variant also receives output codes, the original signal (which was the module signal at the end of the sender), from the accepted amplitude modified signal. It is used to deploy a signal carrying original information in a network carrier wave. A demodulator is an electronic circuit (or a computer program on a defined radio program) that is used to retrieve information content from a modified network carrier.

Envelope Detector

The detector acts as a demodulator. The role of the envelope detector is to recover the modulating signal (which was the original signal at the end of the sender) from the received amplitude modulated signal. The presence of a half-wave rectifier in the envelope detector makes sure that the received AM signal is precise. This is followed by a low throughput filter that removes (bypasses) the wave of the network carrier with the highest frequency signal received. The output effect of the low pass filter will be the original input (correction) signal.

Conclusion

With the introduction of continuous sine wave signals, transmission improved significantly, and soon AM became the standard for voice transmission. Today, amplitude modulation, AM, is used for audio broadcasting in long and medium wave bands, as well as for two-way radio communication via aircraft high frequency. However, as there are now more efficient and simple 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 the way it uses energy transfer. This is the reason 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.