1B Paper 6: Communications Handout 2: Analogue Modulation
|
|
- Tracy Simon
- 5 years ago
- Views:
Transcription
1 1B Paper 6: Communications Handout : Analogue Modulation Ramji Venkataramanan Signal Processing and Communications Lab Department of Engineering ramji.v@eng.cam.ac.uk Lent Term 16 1 / 3 Modulation Modulation is the process by which some characteristic of a carrier wave is varied in accordance with an information bearing signal A commonly used carrier is a sinusoidal wave, e.g., cos(πf c t). f c is called the carrier frequency. We are allotted a certain bandwidth centred around f c for our information signal E.g. BBC Cambridgeshire: f c = 96 MHz, information bandwidth KHz Q: Why is f c usually large? A: Antenna size λ c larger frequency, smaller antennas! / 3
2 Analogue vs. Digital Modulation Analogue Modulation: A continuous information signal x(t) (e.g., speech, audio) is used to directly modulate the carrier wave. We ll study two kinds of analogue modulation: 1. Amplitude Modulation (AM) : Information x(t) modulates the amplitude of the carrier wave. Frequency Modulation (FM): Information x(t) modulates the frequency of the carrier wave We ll learn about: Power & bandwidth of AM & FM signals Tx & Rx design In the last 4 lectures, we will study digital modulation: x(t) is first digitised into bits Digital modulation then used to transport bits across the channel 3 / 3 Amplitude Modulation (AM) Information signal x(t), carrier cos(πf c t) The transmitted AM signal is s AM (t) = [a + x(t)] cos(πf c t) a is a positive constant chosen so that max t x(t) < a The modulation index of the AM signal is defined as m A = max t x(t) a The percentage that the carrier s amplitude varies above and below its unmodulated level Why is the modulation index important? m a < 1 is desirable because we can extract the information signal x(t) from the modulated signal by envelope detection. 4 / 3
3 When modulation index > 1: Phase reversals occur x(t) cannot be detected by tracing the +ve envelope 5 / 3 AM Receiver - Envelope Detector s AM (t) C R L V out (t) On the positive half-cycle of the input signal, capacitor C charges rapidly up to the peak value of input s AM (t) When input signal falls below this peak, diode becomes reverse-biased: capacitor discharges slowly through load resistor R L In the next positive half-cycle, when input signal becomes greater than voltage across the capacitor, diode conducts again until next peak value Process repeats... Very inexpensive receiver, but envelope detection needs m A < 1. 6 / 3
4 CircuitDiagram AM waveinput Envelopedetectoroutput 7 / 3 Spectrum of AM Next, let s look at the spectrum of s AM (t) = [a + x(t)] cos(πf c t) S AM (f ) = F[s AM (t)] [ = F [a + x(t)] (ejπf c t + e jπf c t ] ) = a [δ(f f c) + δ(f + f c )] }{{} carrier + 1 [X (f f c) + X (f + f c )] }{{} information (F[.] denotes the Fourier transform operation) 8 / 3
5 Example S AM (f ) = a [δ(f f c) + δ(f + f c )] + 1 [X (f f c) + X (f + f c )] X(f) C W W f a / S AM (f) a / C/ C/ f c W f c f c + W f c W f c f c + W 9 / 3 Properties of AM s AM (t) = [a + x(t)] cos(πf c t) S AM (f ) = a [δ(f f c) + δ(f + f c )] + 1 [X (f f c) + X (f + f c )] 1. Bandwidth: From spectrum calculation, we see that if x(t) is a baseband signal with (one-sided) bandwidth W, the AM signal s AM (t) is passband with bandwidth B AM = W. Power: We now prove that the power of the AM signal is where P X is the power of x(t) P AM = a + P X 1 / 3
6 Power of AM signal P AM = lim T = lim T 1 T 1 T T T = a + P X + lim T [a + x(t)] cos (πf c t) dt [a + x(t)] 1 + cos(4πf ct) dt 1 T T [a + x(t)] cos(4πf c t) dt We now show that the last the last term is. cos(4πf c t) is a high-frequency sinusoid with period T c = 1 f c. g(t) = (a +x(t)) is a baseband signal which changes much more slowly than cos(4πf c t). Hence, with T = nt c, we have 1 T T g(t) cos(4πf c t) dt 1 ( Tc g() cos(4πf c t) dt + nt c Tc + T c g(t c ) cos(4πf c t) dt... + ntc ) g((n 1)T c ) cos(4πf c t) dt = (n 1)T c Hence P AM = a + P X. 11 / 3 Double Sideband Suppressed Carrier (DSB-SC) The power of AM signal is P AM = a }{{} carrier + P X The presence of a makes envelope detection possible, but requires extra power of a corresponding to the carrier In DSB-SC, we eliminate the a : We transmit only the sidebands, and suppress the carrier X(f) W W f S dsb sc (f) Lower Sideband Upper Sideband f c W f c f c + W f c W f c f c + W 1 / 3
7 DSB-SC ctd. The transmitted DSB-SC wave is s dsb-sc (t) = x(t) cos(πf c t) X(f) W W f S dsb sc (f) Lower Sideband Upper Sideband f c W f c f c + W f c W f c f c + W How to recover x(t) at the receiver? Phase reversals cannot use envelope detection 13 / 3 DSB-SC receiver DSB-SC Receiver: Product Modulator + Low-pass filter s dsb sc (t) v(t) Low-pass filter ˆx(t) cos(πf c t) 1. Multiplying received signal by cos(πf c t) gives v(t) = x(t) cos (πf c t) = x(t) }{{} low freq. + x(t) cos(4πf ct) }{{} high freq.. Low-pass filter eliminates the high-frequency component Ideal low-pass filter has H(f ) = constant for W f W, and zero otherwise 14 / 3
8 Properties of DSB-SC s dsb-sc (t) = x(t) cos(πf c t) S dsb-sc (f ) = 1 (X (f + f c) + X (f f c )) Bandwidth of DSB-SC is B dsb-sc = W, same as AM Power of DSB SC is P dsb-sc = P X (follows from AM power calculation) DSB-SC requires less power than AM as the carrier is not transmitted But DSB-SC receiver is more complex than AM! We assumed that receiver can generate locally generate a frequency f c sinusoid that is synchronised perfectly in phase and frequency with transmitter s carrier Effect of phase mismatch at Rx is explored in Examples paper 15 / 3 Single Sideband Suppressed Carrier (SSB-SC) DSB-SC transmits less power than AM. Can we also save bandwidth? x(t) is real X ( f ) = X (f ) Need to specify X (f ) only for f > In other words, transmission of both sidebands is not strictly necessary: we could obtain one sideband from the other! X(f) W S ssb sc (f) W f Upper Sideband f c W f c f c f c + W Bandwidth is B ssb-sc = W, half of that of AM or DSB-SC! Power is is P ssb-sc = P X 4, half of DSB-SC 16 / 3
9 Summary: Amplitude Modulation X(f) Information signal W W f S AM (f) AM f c W f c f c + W f c W f c f c + W S dsb sc (f) DSB-SC f c W f c f c + W f c W f c f c + W S ssb sc (f) SSB-SC f c W f c f c f c + W 17 / 3 You can now do Questions 1 5 on Examples Paper / 3
10 Frequency Modulation (FM) In FM, the information signal x(t) modulates the instantaneous frequency of the carrier wave. The instantaneous frequency f (t) is varied linearly with x(t): f (t) = f c + k f x(t) This translates to an instantaneous phase θ(t) given by θ(t) = π t t f (u)dt = πf c t + πk f x(u)du The modulated FM signal t s FM (t) = A c cos(θ(t)) = A c cos (πf c t + πk f A c is the carrier amplitude k f is called the frequency-sensitivity factor ) x(u)du 19 / 3 Example What information signal does this FM wave correspond to? s FM (t) t (a) a constant, (b) a ramp, (c) a sinusoid, (d) no clue / 3
11 FM Demodulation At the receiver, how do we recover x(t) from the FM wave? (ignoring effects of noise) t s FM (t) = A c cos (πf c t + πk f ) x(u)du The derivative is ds FM (t) t = πa c [f c + k f x(t)] sin (πf c t + πk f dt ) x(u)du The derivative is a passband signal with amplitude modulation by [f c + k f x(t)] If f c large enough, we can recover x(t) by envelope detection of ds FM(t) dt! Hence FM demodulator is a differentiator + envelope detector d F Differentiator: dt jπf (frequency response). See Haykin-Moher book for details on how to build a differentiator 1 / 3 Properties of FM t s FM (t) = A c cos (πf c t + πk f ) x(u)du Power of FM signal = A c, regardless of x(t) Non-linearity: FM(x 1 (t) + x (t)) FM(x 1 (t)) + FM(x (t)) FM is more robust to additive noise than AM. Intuitively, this is because the message is hidden in the frequency of the signal rather than the amplitude. But this robustness comes at the cost of increased transmission bandwidth What is the bandwidth of the FM signal s FM (t)? The spectral analysis is a bit complicated, but we will do it for a simple case... where x(t) is a sinusoid (a pure tone) / 3
12 FM modulation of a tone Consider FM modulation of a tone x(t) = a x cos(πf x t). We have f (t) = f c + k f a x cos(πf x t) θ(t) = πf c t + k f a x f x sin(πf x t) f = k f a x is called the frequency deviation f is the max. deviation of the carrier frequency f (t) from f c β = k f a x f x = f f x is called the modulation index β is the max. deviation of the carrier phase θ(t) from πf c t Then the FM signal becomes s FM (t) = A c cos (πf c t + β sin(πf x t)) 3 / 3 The spectrum of the FM signal We want to understand the frequency spectrum of s FM (t) = A c cos (πf c t + β sin(πf x t)) We can write where s FM (t) = Re [A ] c e jπf c t + jβ sin(πf x t) = Re [ s(t)e ] jπf ct s(t) = A c e jβ sin(πf x t) s(t) is periodic with period 1/f x Can express using Fourier series (Fundamental frequency f x ) s(t) = c n e jπf x nt n= 4 / 3
13 FM Spectrum ctd. You will show in Examples Paper 8 that the Fourier series coefficients of s(t) are where J n (β) = 1 π c n = A c J n (β) π π e j(β sin u nu) du J n (.) is called the nth order Bessel function of the first kind Thus s(t) = A c e jβ sin(πf x t) = c n e jπf x nt = A c n= n J n (β)e jπf x nt. 5 / 3 Therefore s FM (t) = Re [ ] [ s(t)e jπf ct = Re = Re n= [ n= = A c n= c n e jπf x nt e jπf ct ] A c J n (β) e jπ(f c +nf x )t ] J n (β) cos(π(f c + nf x )t) Taking Fourier Transforms, the spectrum of the FM signal is S FM (f ) = A c n= J n (β) [ δ(f f c nf x ) + δ(f + f c + nf x ) ] 6 / 3
14 Plots of Jn (β) vs β n n n n n 7 / 3 Example What is the spectrum of the FM signal when x(t) is a pure tone and the modulation index β = 5? Jn (β) vs n for β = Jn(β) n 8 / 3
15 Example ctd. The spectrum is S FM (f ) = A c n= J n (5) [ δ(f f c nf x ) + δ(f + f c + nf x ) ] X(f) -f x f x S FM (f) -f c f c 9 / 3 Bandwidth of FM signals To summarise, when x(t) has only a single frequency f x, the spectrum of the FM wave is rather complicated: There is a carrier component at f c, and components located symmetrically on either side of f c at f c ± f x, f c ± f x,... The absolute bandwidth is infinite, but... the side components at f c ± nf x become negligible for large enough n Carson s rule for the effective bandwidth of FM signals: 1. The bandwidth of an FM signal generated by modulating a single tone is ( ) B FM f + f x = f β. For an FM signal generated by modulating a general signal x(t) with bandwidth W, the bandwidth B FM f + W (Recall: for any FM wave, f is the frequency deviation around f c ) 3 / 3
16 Example BBC Radio Cambridgeshire: f c = 96 MHz and f = 75 khz. Assuming that the voice/music signals have W = 15 khz, we have and the bandwidth β = f W = = 5 B FM = ( f + W ) = ( ) = 18 khz, while B AM = W = 3 khz FM signals have larger bandwidth than AM, but have better robustness against noise. 31 / 3 Summary: Analogue Modulation Amplitude Modulation with information signal of bandwidth W AM modulated signal: Bandwidth W, high power, simple Rx using envelope detection DSB-SC: Bandwidth W, lower power, more complex Rx SSB-SC: Bandwidth W, even lower power, Rx similar to DSB-SC Frequency Modulation with information signal of bandwidth W : FM signal has constant carrier amplitude constant power Bandwidth of FM signal depends on both β and W Can be significantly greater than W Better robustness to noise than AM the information is hidden in the phase 3 / 3
Communications IB Paper 6 Handout 2: Analogue Modulation
Communications IB Paper 6 Handout 2: Analogue Modulation Jossy Sayir Signal Processing and Communications Lab Department of Engineering University of Cambridge jossy.sayir@eng.cam.ac.uk Lent Term c Jossy
More informationAngle Modulated Systems
Angle Modulated Systems Angle of carrier signal is changed in accordance with instantaneous amplitude of modulating signal. Two types Frequency Modulation (FM) Phase Modulation (PM) Use Commercial radio
More informationAmplitude Modulation Chapter 2. Modulation process
Question 1 Modulation process Modulation is the process of translation the baseband message signal to bandpass (modulated carrier) signal at frequencies that are very high compared to the baseband frequencies.
More informationM(f) = 0. Linear modulation: linear relationship between the modulated signal and the message signal (ex: AM, DSB-SC, SSB, VSB).
4 Analog modulation 4.1 Modulation formats The message waveform is represented by a low-pass real signal mt) such that Mf) = 0 f W where W is the message bandwidth. mt) is called the modulating signal.
More informationSolution to Chapter 4 Problems
Solution to Chapter 4 Problems Problem 4.1 1) Since F[sinc(400t)]= 1 modulation index 400 ( f 400 β f = k f max[ m(t) ] W Hence, the modulated signal is ), the bandwidth of the message signal is W = 00
More information(b) What are the differences between FM and PM? (c) What are the differences between NBFM and WBFM? [9+4+3]
Code No: RR220401 Set No. 1 1. (a) The antenna current of an AM Broadcast transmitter is 10A, if modulated to a depth of 50% by an audio sine wave. It increases to 12A as a result of simultaneous modulation
More informationELE636 Communication Systems
ELE636 Communication Systems Chapter 5 : Angle (Exponential) Modulation 1 Phase-locked Loop (PLL) The PLL can be used to track the phase and the frequency of the carrier component of an incoming signal.
More informationCode No: R Set No. 1
Code No: R05220405 Set No. 1 II B.Tech II Semester Regular Examinations, Apr/May 2007 ANALOG COMMUNICATIONS ( Common to Electronics & Communication Engineering and Electronics & Telematics) Time: 3 hours
More informationSpeech, music, images, and video are examples of analog signals. Each of these signals is characterized by its bandwidth, dynamic range, and the
Speech, music, images, and video are examples of analog signals. Each of these signals is characterized by its bandwidth, dynamic range, and the nature of the signal. For instance, in the case of audio
More information4.1 REPRESENTATION OF FM AND PM SIGNALS An angle-modulated signal generally can be written as
1 In frequency-modulation (FM) systems, the frequency of the carrier f c is changed by the message signal; in phase modulation (PM) systems, the phase of the carrier is changed according to the variations
More informationCommunication Channels
Communication Channels wires (PCB trace or conductor on IC) optical fiber (attenuation 4dB/km) broadcast TV (50 kw transmit) voice telephone line (under -9 dbm or 110 µw) walkie-talkie: 500 mw, 467 MHz
More information3.1 Introduction to Modulation
Haberlesme Sistemlerine Giris (ELE 361) 9 Eylul 2017 TOBB Ekonomi ve Teknoloji Universitesi, Guz 2017-18 Dr. A. Melda Yuksel Turgut & Tolga Girici Lecture Notes Chapter 3 Amplitude Modulation Speech, music,
More informationOutline. Communications Engineering 1
Outline Introduction Signal, random variable, random process and spectra Analog modulation Analog to digital conversion Digital transmission through baseband channels Signal space representation Optimal
More informationAngle Modulation, II. Lecture topics. FM bandwidth and Carson s rule. Spectral analysis of FM. Narrowband FM Modulation. Wideband FM Modulation
Angle Modulation, II Lecture topics FM bandwidth and Carson s rule Spectral analysis of FM Narrowband FM Modulation Wideband FM Modulation Bandwidth of Angle-Modulated Waves Angle modulation is nonlinear
More informationB.Tech II Year II Semester (R13) Supplementary Examinations May/June 2017 ANALOG COMMUNICATION SYSTEMS (Electronics and Communication Engineering)
Code: 13A04404 R13 B.Tech II Year II Semester (R13) Supplementary Examinations May/June 2017 ANALOG COMMUNICATION SYSTEMS (Electronics and Communication Engineering) Time: 3 hours Max. Marks: 70 PART A
More informationSolutions to some sampled questions of previous finals
Solutions to some sampled questions of previous finals First exam: Problem : he modulating signal m(a m coπf m is used to generate the VSB signal β cos[ π ( f c + f m ) t] + (1 β ) cos[ π ( f c f m ) t]
More informationLecture 6. Angle Modulation and Demodulation
Lecture 6 and Demodulation Agenda Introduction to and Demodulation Frequency and Phase Modulation Angle Demodulation FM Applications Introduction The other two parameters (frequency and phase) of the carrier
More informationProblem Set 8 #4 Solution
Problem Set 8 #4 Solution Solution to PS8 Extra credit #4 E. Sterl Phinney ACM95b/100b 1 Mar 004 4. (7 3 points extra credit) Bessel Functions and FM radios FM (Frequency Modulated) radio works by encoding
More informationEE4512 Analog and Digital Communications Chapter 6. Chapter 6 Analog Modulation and Demodulation
Chapter 6 Analog Modulation and Demodulation Chapter 6 Analog Modulation and Demodulation Amplitude Modulation Pages 306-309 309 The analytical signal for double sideband, large carrier amplitude modulation
More informationAM Limitations. Amplitude Modulation II. DSB-SC Modulation. AM Modifications
Lecture 6: Amplitude Modulation II EE 3770: Communication Systems AM Limitations AM Limitations DSB-SC Modulation SSB Modulation VSB Modulation Lecture 6 Amplitude Modulation II Amplitude modulation is
More informationAmplitude Modulation II
Lecture 6: Amplitude Modulation II EE 3770: Communication Systems Lecture 6 Amplitude Modulation II AM Limitations DSB-SC Modulation SSB Modulation VSB Modulation Multiplexing Mojtaba Vaezi 6-1 Contents
More informationCharan Langton, Editor
Charan Langton, Editor SIGNAL PROCESSING & SIMULATION NEWSLETTER Baseband, Passband Signals and Amplitude Modulation The most salient feature of information signals is that they are generally low frequency.
More informationElements of Communication System Channel Fig: 1: Block Diagram of Communication System Terminology in Communication System
Content:- Fundamentals of Communication Engineering : Elements of a Communication System, Need of modulation, electromagnetic spectrum and typical applications, Unit V (Communication terminologies in communication
More informationAmplitude Modulation, II
Amplitude Modulation, II Single sideband modulation (SSB) Vestigial sideband modulation (VSB) VSB spectrum Modulator and demodulator NTSC TV signsals Quadrature modulation Spectral efficiency Modulator
More informationSignals and Systems Lecture 9 Communication Systems Frequency-Division Multiplexing and Frequency Modulation (FM)
Signals and Systems Lecture 9 Communication Systems Frequency-Division Multiplexing and Frequency Modulation (FM) April 11, 2008 Today s Topics 1. Frequency-division multiplexing 2. Frequency modulation
More information3.1 Introduction 3.2 Amplitude Modulation 3.3 Double Sideband-Suppressed Carrier Modulation 3.4 Quadrature-Carrier Multiplexing 3.
Chapter 3 Amplitude Modulation Wireless Information Transmission System Lab. Institute of Communications Engineering g National Sun Yat-sen University Outline 3.1 Introduction 3. Amplitude Modulation 3.3
More informationDT Filters 2/19. Atousa Hajshirmohammadi, SFU
1/19 ENSC380 Lecture 23 Objectives: Signals and Systems Fourier Analysis: Discrete Time Filters Analog Communication Systems Double Sideband, Sub-pressed Carrier Modulation (DSBSC) Amplitude Modulation
More informationANALOGUE TRANSMISSION OVER FADING CHANNELS
J.P. Linnartz EECS 290i handouts Spring 1993 ANALOGUE TRANSMISSION OVER FADING CHANNELS Amplitude modulation Various methods exist to transmit a baseband message m(t) using an RF carrier signal c(t) =
More informationChapter 5. Amplitude Modulation
Chapter 5 Amplitude Modulation So far we have developed basic signal and system representation techniques which we will now apply to the analysis of various analog communication systems. In particular,
More informationUniversity of Toronto Electrical & Computer Engineering ECE 316, Winter 2015 Thursday, February 12, Test #1
Name: Student No.: University of Toronto Electrical & Computer Engineering ECE 36, Winter 205 Thursday, February 2, 205 Test # Professor Dimitrios Hatzinakos Professor Deepa Kundur Duration: 50 minutes
More informationProblems from the 3 rd edition
(2.1-1) Find the energies of the signals: a) sin t, 0 t π b) sin t, 0 t π c) 2 sin t, 0 t π d) sin (t-2π), 2π t 4π Problems from the 3 rd edition Comment on the effect on energy of sign change, time shifting
More informationAmplitude Modulated Systems
Amplitude Modulated Systems Communication is process of establishing connection between two points for information exchange. Channel refers to medium through which message travels e.g. wires, links, or
More informationWireless Communication Fading Modulation
EC744 Wireless Communication Fall 2008 Mohamed Essam Khedr Department of Electronics and Communications Wireless Communication Fading Modulation Syllabus Tentatively Week 1 Week 2 Week 3 Week 4 Week 5
More informationANALOG (DE)MODULATION
ANALOG (DE)MODULATION Amplitude Modulation with Large Carrier Amplitude Modulation with Suppressed Carrier Quadrature Modulation Injection to Intermediate Frequency idealized system Software Receiver Design
More informationChapter 3: Analog Modulation Cengage Learning Engineering. All Rights Reserved.
Contemporary Communication Systems using MATLAB Chapter 3: Analog Modulation 2013 Cengage Learning Engineering. All Rights Reserved. 3.1 Preview In this chapter we study analog modulation & demodulation,
More informationELEC3242 Communications Engineering Laboratory Amplitude Modulation (AM)
ELEC3242 Communications Engineering Laboratory 1 ---- Amplitude Modulation (AM) 1. Objectives 1.1 Through this the laboratory experiment, you will investigate demodulation of an amplitude modulated (AM)
More informationLinear Frequency Modulation (FM) Chirp Signal. Chirp Signal cont. CMPT 468: Lecture 7 Frequency Modulation (FM) Synthesis
Linear Frequency Modulation (FM) CMPT 468: Lecture 7 Frequency Modulation (FM) Synthesis Tamara Smyth, tamaras@cs.sfu.ca School of Computing Science, Simon Fraser University January 26, 29 Till now we
More informationUNIT I AMPLITUDE MODULATION
UNIT I AMPLITUDE MODULATION Prepared by: S.NANDHINI, Assistant Professor, Dept. of ECE, Sri Venkateswara College of Engineering, Sriperumbudur, Tamilnadu. CONTENTS Introduction to communication systems
More informationLecture 2. FOURIER TRANSFORMS AM and FM
Lecture 2 FOURIER TRANSFORMS AM and FM We saw in the supplement on power spectra that the human range of hearing is concentrated in the range 4Hz to about 4Hz. That s where we d expect radio broadcasts
More informationAnalog Communication.
Analog Communication Vishnu N V Tele is Greek for at a distance, and Communicare is latin for to make common. Telecommunication is the process of long distance communications. Early telecommunications
More informationCS311: Data Communication. Transmission of Analog Signal - I
CS311: Data Communication Transmission of Analog Signal - I by Dr. Manas Khatua Assistant Professor Dept. of CSE IIT Jodhpur E-mail: manaskhatua@iitj.ac.in Web: http://home.iitj.ac.in/~manaskhatua http://manaskhatua.github.io/
More informationLaboratory 3: Frequency Modulation
Laboratory 3: Frequency Modulation Cory J. Prust, Ph.D. Electrical Engineering and Computer Science Department Milwaukee School of Engineering Last Update: 20 December 2018 Contents 0 Laboratory Objectives
More informationCME312- LAB Manual DSB-SC Modulation and Demodulation Experiment 6. Experiment 6. Experiment. DSB-SC Modulation and Demodulation
Experiment 6 Experiment DSB-SC Modulation and Demodulation Objectives : By the end of this experiment, the student should be able to: 1. Demonstrate the modulation and demodulation process of DSB-SC. 2.
More informationCommunications IB Paper 6 Handout 3: Digitisation and Digital Signals
Communications IB Paper 6 Handout 3: Digitisation and Digital Signals Jossy Sayir Signal Processing and Communications Lab Department of Engineering University of Cambridge jossy.sayir@eng.cam.ac.uk Lent
More informationMaster Degree in Electronic Engineering
Master Degree in Electronic Engineering Analog and telecommunication electronic course (ATLCE-01NWM) Miniproject: Baseband signal transmission techniques Name: LI. XINRUI E-mail: s219989@studenti.polito.it
More informationUNIT-2 Angle Modulation System
UNIT-2 Angle Modulation System Introduction There are three parameters of a carrier that may carry information: Amplitude Frequency Phase Frequency Modulation Power in an FM signal does not vary with modulation
More informationPULSE SHAPING AND RECEIVE FILTERING
PULSE SHAPING AND RECEIVE FILTERING Pulse and Pulse Amplitude Modulated Message Spectrum Eye Diagram Nyquist Pulses Matched Filtering Matched, Nyquist Transmit and Receive Filter Combination adaptive components
More informationAmplitude Modulation. Amplitude Modulation. Amplitude Modulation. Amplitude Modulation. A. Introduction. A. Introduction
1. In AM modulation we impart the information of a message signal m(t) on to a sinusoidal carrier c(t). This results in the translation of the message signal to a new frequency range. The motivation for
More informationTHE STATE UNIVERSITY OF NEW JERSEY RUTGERS. College of Engineering Department of Electrical and Computer Engineering
THE STATE UNIVERSITY OF NEW JERSEY RUTGERS College of Engineering Department of Electrical and Computer Engineering 332:322 Principles of Communications Systems Spring Problem Set 3 1. Discovered Angle
More informationAngle Modulation. Frequency Modulation
Angle Modulation Contrast to AM Generalized sinusoid: v(t)=v max sin(ωt+φ) Instead of Varying V max, Vary (ωt+φ) Angle and Pulse Modulation - 1 Frequency Modulation Instantaneous Carrier Frequency f i
More informationpage 7.51 Chapter 7, sections , pp Angle Modulation No Modulation (t) =2f c t + c Instantaneous Frequency 2 dt dt No Modulation
page 7.51 Chapter 7, sections 7.1-7.14, pp. 322-368 Angle Modulation s(t) =A c cos[(t)] No Modulation (t) =2f c t + c s(t) =A c cos[2f c t + c ] Instantaneous Frequency f i (t) = 1 d(t) 2 dt or w i (t)
More informationCHAPTER 2! AMPLITUDE MODULATION (AM)
CHAPTER 2 AMPLITUDE MODULATION (AM) Topics 2-1 : AM Concepts 2-2 : Modulation Index and Percentage of Modulation 2-3 : Sidebands and the Frequency Domain 2-4 : Single-Sideband Modulation 2-5 : AM Power
More informationEECE 301 Signals & Systems Prof. Mark Fowler
EECE 301 Signals & Systems Prof. Mark Fowler Note Set #16 C-T Signals: Using FT Properties 1/12 Recall that FT Properties can be used for: 1. Expanding use of the FT table 2. Understanding real-world concepts
More informationModulations Analog Modulations Amplitude modulation (AM) Linear modulation Frequency modulation (FM) Phase modulation (PM) cos Angle modulation FM PM Digital Modulations ASK FSK PSK MSK MFSK QAM PAM Etc.
More informationEE470 Electronic Communication Theory Exam II
EE470 Electronic Communication Theory Exam II Open text, closed notes. For partial credit, you must show all formulas in symbolic form and you must work neatly!!! Date: November 6, 2013 Name: 1. [16%]
More informationProject 2 - Speech Detection with FIR Filters
Project 2 - Speech Detection with FIR Filters ECE505, Fall 2015 EECS, University of Tennessee (Due 10/30) 1 Objective The project introduces a practical application where sinusoidal signals are used to
More informationCommunications IB Paper 6 Handout 5: Multiple Access
Communications IB Paper 6 Handout 5: Multiple Access Jossy Sayir Signal Processing and Communications Lab Department of Engineering University of Cambridge jossy.sayir@eng.cam.ac.uk Lent Term Jossy Sayir
More informationOutline. Analog Communications. Lecture 03 Linear Modulation. Linear Modulation. Double Side Band (DSB) Modulation. Pierluigi SALVO ROSSI
Outline Analog Communications Lecture 03 Linear Modulation Pierluigi SALVO ROSSI Department of Industrial and Information Engineering Second University of Naples Via Roma 29, 81031 Aversa (CE), Italy homepage:
More informationIntroduction to Amplitude Modulation
1 Introduction to Amplitude Modulation Introduction to project management. Problem definition. Design principles and practices. Implementation techniques including circuit design, software design, solid
More informationLab10: FM Spectra and VCO
Lab10: FM Spectra and VCO Prepared by: Keyur Desai Dept. of Electrical Engineering Michigan State University ECE458 Lab 10 What is FM? A type of analog modulation Remember a common strategy in analog modulation?
More informationEECS 307: Lab Handout 2 (FALL 2012)
EECS 307: Lab Handout 2 (FALL 2012) I- Audio Transmission of a Single Tone In this part you will modulate a low-frequency audio tone via AM, and transmit it with a carrier also in the audio range. The
More informationPart-I. Experiment 6:-Angle Modulation
Part-I Experiment 6:-Angle Modulation 1. Introduction 1.1 Objective This experiment deals with the basic performance of Angle Modulation - Phase Modulation (PM) and Frequency Modulation (FM). The student
More informationMassachusetts Institute of Technology Dept. of Electrical Engineering and Computer Science Fall Semester, Introduction to EECS 2
Massachusetts Institute of Technology Dept. of Electrical Engineering and Computer Science Fall Semester, 2006 6.082 Introduction to EECS 2 Modulation and Demodulation Introduction A communication system
More informationDescription of the AM Superheterodyne Radio Receiver
Superheterodyne AM Radio Receiver Since the inception of the AM radio, it spread widely due to its ease of use and more importantly, it low cost. The low cost of most AM radios sold in the market is due
More informationDSP First. Laboratory Exercise #7. Everyday Sinusoidal Signals
DSP First Laboratory Exercise #7 Everyday Sinusoidal Signals This lab introduces two practical applications where sinusoidal signals are used to transmit information: a touch-tone dialer and amplitude
More informationAmplitude Modulation. Ahmad Bilal
Amplitude Modulation Ahmad Bilal 5-2 ANALOG AND DIGITAL Analog-to-analog conversion is the representation of analog information by an analog signal. Topics discussed in this section: Amplitude Modulation
More informationVestigial Sideband Modulation KEEE343 Communication Theory Lecture #11, April 7, Prof. Young-Chai Ko
Vestigial Sideband Modulation KEEE343 Communication Theory Lecture #11, April 7, 2011 Prof. Young-Chai Ko koyc@korea.ac.kr Summary Vestigial sideband modulation Baseband representation of modulated wave
More informationLaboratory Assignment 5 Amplitude Modulation
Laboratory Assignment 5 Amplitude Modulation PURPOSE In this assignment, you will explore the use of digital computers for the analysis, design, synthesis, and simulation of an amplitude modulation (AM)
More informationUNIT 1 QUESTIONS WITH ANSWERS
UNIT 1 QUESTIONS WITH ANSWERS 1. Define modulation? Modulation is a process by which some characteristics of high frequency carrier signal is varied in accordance with the instantaneous value of the modulating
More informationEECS 216 Winter 2008 Lab 2: FM Detector Part II: In-Lab & Post-Lab Assignment
EECS 216 Winter 2008 Lab 2: Part II: In-Lab & Post-Lab Assignment c Kim Winick 2008 1 Background DIGITAL vs. ANALOG communication. Over the past fifty years, there has been a transition from analog to
More informationDEPARTMENT OF E.C.E.
PVP SIDDHARTHA INSTITUTE OF TECHNOLOGY, KANURU, VIJAYAWADA-7 DEPARTMENT OF E.C.E. ANALOG COMMUNICATIONS LAB MANUAL Department of Electronics & Communication engineering Prasad V.Potluri Siddhartha Institute
More informationChapter 3. Amplitude Modulation Fundamentals
Chapter 3 Amplitude Modulation Fundamentals Topics Covered 3-1: AM Concepts 3-2: Modulation Index and Percentage of Modulation 3-3: Sidebands and the Frequency Domain 3-4: AM Power 3-5: Single-Sideband
More informationChapter 3 Data Transmission COSC 3213 Summer 2003
Chapter 3 Data Transmission COSC 3213 Summer 2003 Courtesy of Prof. Amir Asif Definitions 1. Recall that the lowest layer in OSI is the physical layer. The physical layer deals with the transfer of raw
More informationWireless PHY: Modulation and Demodulation
Wireless PHY: Modulation and Demodulation Y. Richard Yang 09/6/2012 Outline Admin and recap Frequency domain examples Basic concepts of modulation Amplitude modulation Amplitude demodulation frequency
More informationEE-4022 Experiment 3 Frequency Modulation (FM)
EE-4022 MILWAUKEE SCHOOL OF ENGINEERING 2015 Page 3-1 Student Objectives: EE-4022 Experiment 3 Frequency Modulation (FM) In this experiment the student will use laboratory modules including a Voltage-Controlled
More informationECE 359 Spring 2003 Handout # 16 April 15, SNR for ANGLE MODULATION SYSTEMS. v(t) = A c cos(2πf c t + φ(t)) for FM. for PM.
ECE 359 Spring 23 Handout # 16 April 15, 23 Recall that for angle modulation: where The modulation index: ag replacements SNR for ANGLE MODULATION SYSTEMS v(t) = A c cos(2πf c t + φ(t)) t 2πk f m(t )dt
More informationTheory of Telecommunications Networks
Theory of Telecommunications Networks Anton Čižmár Ján Papaj Department of electronics and multimedia telecommunications CONTENTS Preface... 5 1 Introduction... 6 1.1 Mathematical models for communication
More informationPart A: Question & Answers UNIT I AMPLITUDE MODULATION
PANDIAN SARASWATHI YADAV ENGINEERING COLLEGE DEPARTMENT OF ELECTRONICS & COMMUNICATON ENGG. Branch: ECE EC6402 COMMUNICATION THEORY Semester: IV Part A: Question & Answers UNIT I AMPLITUDE MODULATION 1.
More informationAngle Modulation KEEE343 Communication Theory Lecture #12, April 14, Prof. Young-Chai Ko
Angle Modulation KEEE343 Communication Theory Lecture #12, April 14, 2011 Prof. Young-Chai Ko koyc@korea.ac.kr Summary Frequency Division Multiplexing (FDM) Angle Modulation Frequency-Division Multiplexing
More informationPart I - Amplitude Modulation
EE/CME 392 Laboratory 1-1 Part I - Amplitude Modulation Safety: In this lab, voltages are less than 15 volts and this is not normally dangerous to humans. However, you should assemble or modify a circuit
More informationCommunications and Signals Processing
Communications and Signals Processing Department of Communications An Najah National University 2012/2013 1 3.1 Amplitude Modulation 3.2 Virtues, Limitations, and Modifications of Amplitude Modulation
More informationFaculty of Engineering Electrical Engineering Department Communication Engineering I Lab (EELE 3170) Eng. Adam M. Hammad
Faculty of Engineering Electrical Engineering Department Communication Engineering I Lab (EELE 3170) Eng. Adam M. Hammad EXPERIMENT #5 DSB-SC AND SSB MODULATOR Theory The amplitude-modulated signal is
More informationCOMM 601: Modulation I
Prof. Ahmed El-Mahdy, Communications Department The German University in Cairo Text Books [1] Couch, Digital and Analog Communication Systems, 7 th edition, Prentice Hall, 2007. [2] Simon Haykin, Communication
More informationExperiment 7: Frequency Modulation and Phase Locked Loops
Experiment 7: Frequency Modulation and Phase Locked Loops Frequency Modulation Background Normally, we consider a voltage wave form with a fixed frequency of the form v(t) = V sin( ct + ), (1) where c
More informationELEC 350 Communications Theory and Systems: I. Review. ELEC 350 Fall
ELEC 350 Communications Theory and Systems: I Review ELEC 350 Fall 007 1 Final Examination Saturday, December 15-3 hours Two pages of notes allowed Calculator Tables provided Fourier transforms Table.1
More informationEC2252: COMMUNICATION THEORY SEM / YEAR: II year DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING
EC2252: COMMUNICATION THEORY SEM / YEAR: II year DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK SUBJECT CODE : EC2252 SEM / YEAR : II year SUBJECT NAME : COMMUNICATION THEORY UNIT
More informationMusic 270a: Modulation
Music 7a: Modulation Tamara Smyth, trsmyth@ucsd.edu Department of Music, University of California, San Diego (UCSD) October 3, 7 Spectrum When sinusoids of different frequencies are added together, the
More informationEE456 Digital Communications
EE456 Digital Communications Professor Ha Nguyen September 216 EE456 Digital Communications 1 Angle Modulation In AM signals the information content of message m(t) is embedded as amplitude variation of
More informationCOMMUNICATION SYSTEMS-II (In continuation with Part-I)
MODULATING A SIGNAL COMMUNICATION SYSTEMS-II (In continuation with Part-I) TRANSMITTING SIGNALS : In order to transmit the original low frequency baseband message efficiently over long distances, the signal
More informationEE390 Frequency Modulation/Demodulation Lab #4
EE390 Frequency Modulation/Demodulation Lab #4 Objective Observe FM signals in both the time and frequency domain while making basic measurements. Equipment used. The Dual Function Generator: A feature
More informationModulation is the process of impressing a low-frequency information signal (baseband signal) onto a higher frequency carrier signal
Modulation is the process of impressing a low-frequency information signal (baseband signal) onto a higher frequency carrier signal Modulation is a process of mixing a signal with a sinusoid to produce
More information5.1. Amplitude Modula1on
5.1. Amplitude Modula1on The complex envelope of an AM signal is given by g(t) = A c [1+ m(t)] where the constant A c has been included to specify the power level and m(t) is the modula
More informationFrequency Modulation KEEE343 Communication Theory Lecture #15, April 28, Prof. Young-Chai Ko
Frequency Modulation KEEE343 Communication Theory Lecture #15, April 28, 2011 Prof. Young-Chai Ko koyc@korea.ac.kr Summary Angle Modulation Properties of Angle Modulation Narrowband Frequency Modulation
More informationLab course Analog Part of a State-of-the-Art Mobile Radio Receiver
Communication Technology Laboratory Wireless Communications Group Prof. Dr. A. Wittneben ETH Zurich, ETF, Sternwartstrasse 7, 8092 Zurich Tel 41 44 632 36 11 Fax 41 44 632 12 09 Lab course Analog Part
More informationCHAPTER 3 Noise in Amplitude Modulation Systems
CHAPTER 3 Noise in Amplitude Modulation Systems NOISE Review: Types of Noise External (Atmospheric(sky),Solar(Cosmic),Hotspot) Internal(Shot, Thermal) Parameters of Noise o Signal to Noise ratio o Noise
More informationUNIT-I AMPLITUDE MODULATION (2 Marks Questions and Answers)
UNIT-I AMPLITUDE MODULATION (2 Marks Questions and Answers) 1. Define modulation? Modulation is a process by which some characteristics of high frequency carrier Signal is varied in accordance with the
More informationExperiment 1 Design of Conventional Amplitude Modulator
Name and ID: Preliminary Work Group Number: Date: Experiment 1 Design of Conventional Amplitude Modulator 1. Using the information given in this assignment, design your switching modulator that modulates
More informationDIGITAL COMMUNICATIONS SYSTEMS. MSc in Electronic Technologies and Communications
DIGITAL COMMUNICATIONS SYSTEMS MSc in Electronic Technologies and Communications Bandpass binary signalling The common techniques of bandpass binary signalling are: - On-off keying (OOK), also known as
More information! Amplitude of carrier wave varies a mean value in step with the baseband signal m(t)
page 7.1 CHAPTER 7 AMPLITUDE MODULATION Transmit information-bearing (message) or baseband signal (voice-music) through a Communications Channel Baseband = band of frequencies representing the original
More informationInternal Examination I Answer Key DEPARTMENT OF CSE & IT. Semester: III Max.Marks: 100
NH 67, Karur Trichy Highways, Puliyur C.F, 639 114 Karur District Internal Examination I Answer Key DEPARTMENT OF CSE & IT Branch & Section: II CSE & IT Date & Time: 06.08.15 & 3 Hours Semester: III Max.Marks:
More information