File Name: types of modulation and demodulation .zip
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.
- What is Modulation and Different Types
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- Modulation Methods
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?
What is Modulation and Different Types
Demodulation is extracting the original information-bearing signal from a carrier wave. A demodulator is an electronic circuit or computer program in a software-defined radio that is used to recover the information content from the modulated carrier wave. The signal output from a demodulator may represent sound an analog audio signal , images an analog video signal or binary data a digital signal. These terms are traditionally used in connection with radio receivers , but many other systems use many kinds of demodulators. Demodulation was first used in radio receivers. In the wireless telegraphy radio systems used during the first 3 decades of radio the transmitter did not communicate audio sound but transmitted information in the form of pulses of radio waves that represented text messages in Morse code. Therefore, the receiver merely had to detect the presence or absence of the radio signal, and produce a click sound.
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. In this process video, voice and other data signals modify high-frequency signals — also known as the carrier wave.
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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.
Modulation is the process of converting data into electrical signals optimized for transmission. Modulation techniques are roughly divided into four types: Analog modulation, Digital modulation, Pulse modulation , and Spread spectrum method. This method is divided into single carrier modulation, by which the carrier occupies the entire bandwidth i. In addition, there is a pulse modulation technique used to change the pulse width and spread spectrum method that spreads the signal energy over a wide band. In wireless communication, information is transmitted by encoding voice and data on radio waves of certain frequencies.
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.
Satellite Communication Systems pp Cite as. In chapter 4 we learnt the basics of radio link design. The design goal was to achieve a specified carrier-to-noise ratio at the demodulator input.
Фонд электронных границ сразу увидел в этом конфликт интересов и всячески пытался доказать, что АНБ намеренно создаст несовершенный алгоритм - такой, какой ему будет нетрудно взломать. Чтобы развеять эти опасения, конгресс объявил, что, когда алгоритм будет создан, его передадут для ознакомления лучшим математикам мира, которые должны будут оценить его качество. Команда криптографов АНБ под руководством Стратмора без особого энтузиазма создала алгоритм, который окрестила Попрыгунчиком, и представила его в конгресс для одобрения. Зарубежные ученые-математики проверили Попрыгунчика и единодушно подтвердили его высокое качество. Они заявляли, что это сильный, чистый алгоритм, который может стать отличным стандартом шифрования. Но за три дня до голосования в конгрессе, который наверняка бы дал добро новому стандарту. молодой программист из лаборатории Белл по имени Грег Хейл потряс мир, заявив, что нашел черный ход, глубоко запрятанный в этом алгоритме.
Это все, что я могу вам сказать. Я уполномочен заплатить вам за. На мгновение в комнате повисла тишина, затем Росио приоткрыла губы в хитрой улыбке.