Collector modulation method is high level amplitude modulation c. Calculate the frequency deviation, modulation index, and bandwidth. For the baseband digital transmission, pulse amplitude modulation pam is the most efficient in terms of power and bandwidth utilization. Solutions to some sampled questions of previous finals. Sampling theorem and pulse amplitude modulation pam reference stremler, communication systems, chapter 3. It is often called as am and is commonly used in transmitting a piece of information through a radio carrier wave. The amplitude modulation theory is applied to twomode buckling of stringer stiffened cylindrical shells under axial compression. A sinusoidal modulating waveform of amplitude 5 v and a frequency of 2 khz is applied to fm generator, which has a frequency sensitivity of 40 hzvolt. The pdf of r is equal to the convolution of the pdfs of s and n. Amplitude modulation theory and its application to twomode buckling problems by david hui, the ohio state university, dept.
In amplitude modulation, the amplitude of the carrier signal varies. Classify each of the signals in the previous problem into even or odd signals, and. Quadratureamplitudemodulationqam dsbsc modulates a signal with bandwidth b to a transmitted signal with bandwidth 2b ssb reduces the transmitted bandwidth to b, but requires more complex modulator reduces snr for a. The amplitude of the analog signal is sampled at uniform intervals and each sample is quantized to its nearest. There are two common forms of angle modulation, namely, phase modulation and frequency modulation. Consequently, the fourier series expansion of ptis pt. In such case the formula for modulation index is given by. Sampling theorem determines the necessary conditions which allow us to change an analog signal to a discrete one. Venkatesha m jrf,research scholar and adjunct faculty department of ece sai vidya institute of technology, bangalore560064. Pulse code modulation is the heart of technology in communications in todays. Sampling theorem and pulse amplitude modulation pam. Various features of this theory are compared with koiters general theory of 1945. Would 16qam be more or less susceptible to noise than this type of modulation. In commercial tv transmission in india, picture and speech signals are.
Basic electronics solved problems by sasmita january 9, 2020. Here you can download the free lecture notes of analog communication system pdf notes ac notes pdf materials with multiple file links to download. Heres our standard modulationdemodulation system diagram. Amplitude modulation am is a modulation technique used in. There is no over modulation means that modulation index is less than or equal to 1. In this lecture, we have solved some questions on single tone amplitude modulation. Modulation is done at high power of carrier and modulating signal b. Analog communication pdf notes book starts with the topics covering introduction ac, dsb modulation, ssb modulation, angle modulation concepts, angle modulation methods, noise etc. Solved numerical problems on common emitter configuration of bjt in hindi duration. The carrier and spurs of problem 3 above are passed through a frequency tripler. Preface progress in telecommunications over the past two decades has been nothing short of revolutionary, with communications taken for granted in modern society to the same extent as electricity.
If correctly designed, 16 qam should in general less susceptible to noise because the symbols would be be. Frequency modulation is the process of varying the frequency of the carrier signal linearly with the message signal. Multiple choice questions and answers on amplitude modulation. The channel decoder attempts to reconstruct the original information sequence from knowledge of the code used by the channel encoder, the digital modulation scheme and the redundancy contained in the received sequence. At the point in time when the modulating cosine wave is zero, the total signal is a 2, so ka 0. The input sequence b k consists of binary digits bits 1 and 0 with a bit duration of t b and a bit rate of r b 1 t b. This ezed video explains the solution to the following university problem the modulating signal of 20 cos2 pi 103 t is used to. The use of amplitudemodulated analog carriers to transport digital information is a relatively lowquality, lowcost type of digital modulation and, therefore, is seldom used except for very lowspeed telemetry circuits. In this chapter, let us solve a few problems based on the concept of frequency modulation. Its primary purpose is to map the information sequence into signal waveforms. Next topic pulse code modulation pulsecode modulation pcm is used to digitally represent sampled analog signals. The first transmission of a message using pcm was in 1943 during the world war ii. In general, amplitude modulation definition is given as a type of modulation where the amplitude of the carrier wave is varied in some proportion with respect to the modulating data or the signal.
It is the standard form of digital audio in computers, cds, digital telephony and other digital audio applications. Amplitude modulation is a process by which the wave signal is transmitted by modulating the amplitude of the signal. Amplitude modulation 2 marks questions and answers 1. A typical audio frequency of 3000 hz has a wavelength of 100 km and. Solutions to some sampled questions of previous finals first exam. Angle modulation is the process in which the frequency or the phase of the carrier signal varies according to the message signal. The other type of modulation in continuouswave modulation is angle modulation. Amplitude modulation am is a process by which the wave signal is transmitted by modulating the amplitude of the signal. Amplitude modulation 18 angle modulation 3 basic electrical engineering 1 basic electronics solved problems 8 big data 2 blogging 1 boolean logic 2. Modulation is a process by which some characteristics of high frequency carrier signal is varied in accordance with the instantaneous value of the modulating signal. The standard equation of the angle modulated wave is in amplitude modulation, the. With few exceptions, phase modulation pm is used primarily in digital communication amplitude, frequency and phase modulation. Amplitude modulation definition, types, solved examples byjus.
Amplitude modulation is mostly used in the form of electronic communication. As given is the problem the modulation is sinusoidal this is also called tone modulation. Introduction koiters theory of amplitude modulation of the local mode is a very useful. As for the mechanism, when amplitude modulation is used there is a variation in the amplitude of the carrier. The expression for the general form of amplitude modulation is, vt 1. If the maximum allowed frequency deviation is 50 khz. You can publish your book online for free in a few minutes. Power amplifiers are used to boost the carrier and modulating signals before modulation d. Amplitude modulation definition, types, solved examples. Phase modulation is the process of varying the phase of the carrier signal linearly with the message signal. Pdf analog communication system pdf notes ac notes sw. Pulse amplitude modulation an overview sciencedirect.
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