[Physics Class Notes] on Modulation Pdf for Exam

If you have ever listened to the radio in the car, in your home, you must be aware of FM and AM. Moreover, you will also notice that each radio station has a unique address on the FM and AM scale. Such a phenomenon behind radio transmission travelling from your favourite FM station to your audio device is one of the most important uses of modulation. 

From radio stations to various other modes of communication, modulation is significantly important. In this topic, the primary focus will be on what is the need for modulation. 

However, before that, it is vital to understand the fundamentals of modulation. So, check these following concepts which explain the same

What is the Definition of Modulation?

Modulation can be defined as the process of conversion of data into waves by adding information to a carrier signal. Such a signal can be an electronic or an optic carrier, but most importantly, it should possess a steady waveform.

A signal with a steady waveform indicates that it possesses a constant amplitude and frequency. Moreover, one can add information on such a carrier through modulation by altering its frequency, phase, amplitude, polarisation in the case of optical signals as well as electronic or even quantum signals such as varying the spin. 

Why Modulation is Necessary for Communication?

The necessity of modulation is mainly visible in the electronic field as it is applied to electromagnetic signals such as radio waves, lasers, electronic chips, etc. for an efficient mode of communication among various devices. 

For example:

In cases where an engineer needs to control the signals sent by the energy generated by a DC motor, he or she can apply modulation to direct current. Here, it will be treated as a degenerate carrier wave that has a constant amplitude and a fixed frequency.

As per the above example, it is easier to gauge the need of modulation in communication systems. Moreover, one can also turn the modulation ON or OFF, which helps in easier delivery and reception of signals, just like the Morse code theory or direct current loop interface.

Furthermore, in various cases, a modulated signal may turn out to be a ‘no carrier’ which means any response message will indicate that any number of attached devices are no longer connected to the remote network system. Such a phenomenon is known as baseband modulation.

What is Modulation in Communication?

Modulation is an essential process to ease communication between several electromagnetic mediums. Moreover, multiple carriers of data, each having different frequencies can be transmitted over only a single media if an independent signal modulates each carrier.

Additionally, one can also apply modulation to alternating current with a low-rated frequency. Usually, alternating current used in our daily lives has a frequency of 50 to 60 Hz. Modulation can be applied to alternating the current of such frequencies with the help of powerline networking.

Before we carry on with our discussion on why modulation is required, brush up your memory with the help of this ‘fill in the blanks’ section given below –

Test Your Knowledge

Fill in the blanks with the correct answer from the options given below.

1.Modulating waves can also be termed as a _________ wave.

1. comparing 

2. transmission

3. measuring

4. optic

      Ans: b. Measuring

2. Which of the following is constant in the case of frequency modulation?

1. Modulation

2. Wavelength

3. Amplitude

4. Frequency

      Ans: c.  Amplitude

3.One of the most important advantages of modulation is that _______.

1. signal mixing occurs

2. signal mixing does not occur

3. range of communication decreases

4. adjustments in bandwidth are disallowed

      Ans: b. signal mixing does not occur

Types of Modulation

Modulation is of various types based on the alteration of various factors such as frequency, amplitude, etc. on each modulated signal. They are –

• Amplitude modulation (AM)

• Frequency modulation (FM)

• Phase modulation (PM)

• Pulse code modulation

• Polarisation modulation

• Quadrature amplitude modulation (QAM)

Each type of modulation has its own set of advantages and disadvantages. For example, AM is usually used in shortwaves, whereas FM is used in longwave radio transmission.

Conclusion

This is all about different types of modulations and their uses. Learn how different modulations are used in many ways.