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Modulation And Its Types Pdf

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Although one of the earliest used forms of modulation it is still used today, mainly for long, medium and short wave broadcasting and for some aeronautical point to point communications. One of the key reasons for the use of amplitude modulation was its ease of use.

Frequency modulation FM is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave. The technology is used in telecommunications , radio broadcasting , signal processing , and computing. In analog frequency modulation, such as radio broadcasting, of an audio signal representing voice or music, the instantaneous frequency deviation , i. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying FSK , in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies may represent digits, such as 0 and 1.

Communication Systems/What is Modulation?

The term carrier is applied to the voltage whose characteristic is varied and the term modulating voltage signal is used for the voltage in accordance with which the variation is made. The modulation is the process of up shifting the message frequency to a range more useful for transmission. The carrier signal is a sine wave at the carrier frequency. Below equation shows that the sine wave has three characteristics that can be altered. So three forms of modulations are possible.

Amplitude Modulation, AM

In electronics and telecommunications , modulation is the process of varying one or more properties of a periodic waveform , called the carrier signal , with a separate signal called the modulation signal that typically contains information to be transmitted. For example, the modulation signal might be an audio signal representing sound from a microphone , a video signal representing moving images from a video camera , or a digital signal representing a sequence of binary digits, a bitstream from a computer. The carrier is higher in frequency than the modulation signal. The purpose of modulation is to impress the information on the carrier wave, which is used to carry the information to another location. In radio communication the modulated carrier is transmitted through space as a radio wave to a radio receiver. Another purpose is to transmit multiple channels of information through a single communication medium, using frequency division multiplexing FDM. For example in cable television which uses FDM, many carrier signals carrying different television channels are transported through a single cable to customers.

Communication is the basic attraction of mankind as it gives the knowledge of what is going on around us. In our daily life, we communicate with many people and use the entertainment media like television, radio, internet and newspaper to get ourselves involved. These entertainment media act as a source of communication. Electronic communication comprises TV, radio, internet, etc. When we want to transmit a signal from one location to another, we have to strengthen the signal. After undergoing strenghthening process the signal travels to a long distance.

As we are living in an era of communication wherein we can easily transfer any form of information video, audio, and other data in the form of electrical signals to any other device or destined area. Although it is common in our perceptual experience that sending or receiving signals or data is simple, but it involves quite complex procedures, possibilities, and involved scenarios within the communication systems. So, in the scope of communication systems, modulation plays hold crucial responsibility in the communication system to encode information digitally in the analog world. It is very important to modulate the signals before sending them to the receiver section for larger distance transfer, accurate data transfer, and low-noise data reception. To be clear, let us dive into the detailed concept of knowing what is modulation, different types in it, and what are the types of modulation techniques used in communication systems. Modulation is a process of changing the characteristics of the wave to be transmitted by superimposing the message signal on the high-frequency signal.

Principles of Communication - Modulation

Phase modulation PM is a modulation pattern for conditioning communication signals for transmission. It encodes a message signal as variations in the instantaneous phase of a carrier wave. Phase modulation is one of the two principal forms of angle modulation , together with frequency modulation.

Modulation is the process by which information is encoded from a message source in order to optimize it for transmission. Frequency Modulation FM is the encoding of information in a carrier wave by changing the instantaneous frequency of the wave. FM technology is widely used in the fields of computing, telecommunications, and signal processing.

A signal can be anything like a sound wave which comes out when you shout. This shout can be heard only up to a certain distance. A message carrying signal has to get transmitted over a distance and for it to establish a reliable communication, it needs to take the help of a high frequency signal which should not affect the original characteristics of the message signal. The characteristics of the message signal, if changed, the message contained in it also alters. Hence it is a must to take care of the message signal.

Modulation Methods

Need For Modulation

Modulation is a term that is going to be used very frequently in this book. So much in fact, that we could almost have renamed this book "Principles of Modulation", without having to delete too many chapters. So, the logical question arises: What exactly is modulation? Modulation is a process of mixing a signal with a sinusoid to produce a new signal. This new signal, conceivably, will have certain benefits over an un-modulated signal. Mixing of low frequency signal with high frequency carrier signal is called modulation.

Но, увидев прислужника в конце ряда и два людских потока, движущихся по центральному проходу к алтарю, Беккер понял, что происходит. Причастие. Он застонал. Проклятые испанцы начинают службу с причастия. ГЛАВА 92 Сьюзан начала спускаться по лестнице в подсобное помещение. Густые клубы пара окутывали корпус ТРАНСТЕКСТА, ступеньки лестницы были влажными от конденсации, она едва не упала, поскользнувшись. Она нервничала, гадая, сколько еще времени продержится ТРАНСТЕКСТ.

 У нас ничего такого не случалось. - Вот.  - Она едва заметно подмигнула.  - В этом все и. - Мидж… - Доброй ночи, Чед.  - Она направилась к двери.

Types of Modulation Schemes used in Communication Systems

 Сьюзан, выслушай меня, - сказал он, нежно ей улыбнувшись.

 El queria que lo guardara. Он хотел его оставить, но я сказала. Во мне течет цыганская кровь, мы, цыганки, не только рыжеволосые, но еще и очень суеверные. Кольцо, которое отдает умирающий, - дурная примета. - Вы знаете эту девушку? - Беккер приступил к допросу.

 - Пожалуй, я куплю тебе билет. Белокурая девушка смотрела на него недоверчиво. - Вы это сделаете? - выдавила она, и глаза ее засветились надеждой.  - Вы купите мне билет домой.

Пистолет упал на пол. Оба противника оказались на полу. Беккеру удалось оторваться от убийцы, и он рванулся к двери.

Но Мидж эта ситуация явно доставляла удовольствие. Она подошла к окну, вертя бумагу перед глазами, чтобы найти лучший угол для падения лунного света. - Мидж… пошли.

Modulation Methods

Халохот был вынужден скрыться, не успев обыскать убитого, найти ключ. А когда пыль осела, тело Танкадо попало в руки местной полиции. Стратмор был взбешен.


Romana M. 05.05.2021 at 20:05

As we have seen in previous three chapters, different types of media need different transmitted, data are used to modulate or change its amplitude, frequency.

Clarice D. 07.05.2021 at 08:08

Modulation is the process of superimposing a low frequency signal on a high and the listener can (by band selection) retrieve the program of his own choice.

Abraham C. 07.05.2021 at 08:35

Modulation is the process of converting data into electrical signals optimized for transmission.