# Ppt on amplitude shift keying modulation

##### DIGITAL MODULATION. Digital Modulation Basics l The bit rate defines the rate at which information is passed. l The baud (or signaling) rate defines the.

number of phases are used. In the case of FSK, a finite number of frequencies are used. In the case of ASK, a finite number of amplitudes are used. Digital Modulation Digital Modulation Formats ASK PSK FSK Amplitude Shift Keying (ASK) The most basic (binary) form of ASK involves the process of switching the carrier either on or off, in correspondence to a sequence of digital/

##### 1 An Najah National University Telecommunication Engineering Department Digital Communications 69342 Digital Modulation Dr. Allam Mousa Sec3_Dig_Modu.

3*1000 /2 = 1500Hz. 5&3 not necessary to equal. 17Sec3_Dig_Modu Phase Shift Keying (PSK). Angle – modulated, constant – amplitude digital modulation. Analog input Binary digital signal PM PSK Limited number of output phase Binary PSK (BPSK) two phases also called /=2 M=2 = 4 N=3 M=2 = 8 3 1 2 27Sec3_Dig_Modu Quaternary Phase Shift Keying (QPSK) = M=4 QASK angle-modulated, constant – amplitude. Digital modulation. QPSK 1 one carrier & 4 different phases. 2-bits 4 input conditions 4 output phasesQPSK /

##### CHAPTER 4. OUTLINES 1. Digital Modulation Introduction Information capacity, Bits, Bit Rate, Baud, M- ary encoding ASK, FSK, PSK, QPSK, QAM 2. Digital.

M-ary digitally modulated carriers Amplitude Shift Keying (ASK) A binary information signal directly modulates the amplitude of an analog carrier. Sometimes called Digital Amplitude Modulation (DAM) Where v ask (t) = amplitude shift keying wave v m (t) = digital information signal (volt) A/2 = unmodulated carrier amplitude (volt) ω c = analog carrier radian frequency (rad/s) Digital Amplitude Modulation Frequency Shift Keying (FSK) Called as Binary Frequency Shift Keying (BFSK) The phase shift in carrier/

##### Modulation of Digital Data 1.Digital-to-Analog Conversion 2.Amplitude Shift Keying (ASK) 3.Frequency Shift Keying (FSK) 4.Phase Shift Keying (PSK) 5.Quadrature.

.Digital-to-Analog Conversion 2.Amplitude Shift Keying (ASK) 3.Frequency Shift Keying (FSK) 4.Phase Shift Keying (PSK) 5.Quadrature Amplitude Modulation (QAM) 6.Bit/Baud Comparison 7.Modems Digital-to-analog modulation Types of digital-to-analog modulation Aspects to digital-to Analog /signal unit carries 6 bits, what is the baud rate?  Baud rate = 3000/6 =500 bauds/sec Amplitude Shift Keying (ASK) The strength of the carrier signal is varied to represent binary 1 and 0. Frequency and phase remains/

##### Chapter 6 – Modulation Techniques for Mobile Radio

→ “dense” → more signal states/symbol → more information/Hz !! ∴ Bandwidth Efficient IV. Linear Modulation Methods In linear modulation techniques, the amplitude of the transmitted signal varies linearly with the modulating digital signal. Performance is evaluated with respect to Eb / No BPSK BPSK → Binary Phase Shift Keying Phase transitions force carrier amplitude to change from “+” to “−”. Amplitude varies in time BPSK RF signal BW Null-to-null RF BW = 2/

##### Wireless Networking Spread Spectrum Technologies Module-04 Jerry Bernardini Community College of Rhode Island 6/20/20151Wireless Networking J. Bernardini.

occur in discrete steps using binary signals – Uses same three basic types of modulation as analog Amplitude shift keying (ASK) CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini 39 Digital Modulation Frequency shift keying (FSK) Phase shift keying (PSK) CWNA Guide to Wireless LANs, Second Edition 40 Quadrature phase shift keying (QPSK) CWNA Guide to Wireless LANs, Second Edition 41 Physical Layer Standards (continued) Figure 4-21: 16-level quadrature/

##### Wireless Networking Spread Spectrum Technologies Module-05

occur in discrete steps using binary signals Uses same three basic types of modulation as analog Amplitude shift keying (ASK) CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini Digital Modulation Frequency shift keying (FSK) Phase shift keying (PSK) CWNA Guide to Wireless LANs, Second EditionCCRI J. Bernardini Quadrature phase shift keying (QPSK) CWNA Guide to Wireless LANs, Second Edition 16-QAM/

##### Modulation Modulation => Converts from digital to analog signal.

will be m = Vmo/Vco. If m =0.5, the carrier amplitude varies by 50 % . If m= 1.0 then it varies by 100%. Modulation: Amplitude-Shift Keying (ASK) ASK encodes digital data by modulating the carriers amplitude between two or more levels. Suppose a signal with amplitude 1 represents a binary 0 and a signal with amplitude 2 represents a binary 1. AM is more sensitive to noise/

##### Modulation and Demodulation

) + 2) * 5 t) Q: Is the constant “2" necessary here? 13 13 Modulation of Digital Signals A different term: shift keying Instead of a continuum of possible values, digital shift keying has a fixed set Mapping to the power levels of a digital signal a carrier wave a digital input signal amplitude shift keying frequency shift keying Exercise: ASK Consider the input signal with 3 levels shown above. Assume we/

##### Modulation Techniques for Mobile Radio

Pe,QPSK = Q[√(2 EB / N0)] RB – Bit rate, TB – Bit period EB – Energy/bit, N0 – Noise spectral density QPSK BW = RB = 1 / TB Nonlinear or envelope modulation Frequency shift keying The frequency of a constant amplitude carrier signal is switched between 2 values ( 1 and 0) Properties of FSK Transmission Bandwidth BT = 2f + 2B B = Bandwidth of digital base-band signal If/

##### DIGITAL MODULATION. Digital-to-analog modulation (Digital-to-analog modulation)

signal unit carries 6 bits, what is the baud rate? Solution Baud rate = 3000 / 6 = 500 baud/s ASK Describe Amplitude Shift Keying ASK Describe Amplitude Shift Keying Amplitude-shift keying (ASK) is a form of modulation that represents digital data as variations in the amplitude of a carrier wave.modulation digitaldataamplitudecarrier wave The simplest and most common form of ASK operates as a switch, using the presence of a carrier wave/

##### Topic 4 –Data Encoding and Modulation1 FIT1005 FIT – Monash University Topic - Data Encoding And Modulation Reference: Chapter 5 -Stallings.

signals in the voice-frequency range Topic 4 –Data Encoding and Modulation18 Digital Data, Analog Signals Modulation involves operation on one or more of the characteristics of a carrier signal: amplitude, frequency, and phase Modulation techniques for transforming digital data onto analog signals –Amplitude Shift Keying (ASK) –Frequency Shift Keying (FSK) –Phase Shift Keying (PSK) In all these cases, the resulting signal occupies a bandwidth centred on the carrier frequency/

##### Wireless PHY: Modulation and Demodulation Y. Richard Yang 09/11/2012.

( 1, # Decimation rate chan_taps, #coefficients 0, #Offset frequency - could be used to shift 48e3) #incoming sample rate 29 Outline r Recap r Amplitude demodulation m frequency shifting m low pass filter r Digital modulation 30 r Modulation of digital signals also known as Shift Keying r Amplitude Shift Keying (ASK): m vary carrier amp. according to data r Frequency Shift Keying (FSK) o vary carrier freq. according to bit value r Phase/

##### 05 - Winter 2005 ECE ECE 766 Computer Interfacing and Protocols 1 Modulation Conversion of digital information to analog signals –Example: Telephone lines.

information 05 - Winter 2005 ECE ECE 766 Computer Interfacing and Protocols 2 Modulation Modulation Techniques –Amplitude Shift Keying (ASK) –Frequency Shift Keying (FSK) –Phase Shift Keying (PSK) Aspects of Modulation –Bit rate vs. Baud rate Bit rate ≥ Baud rate –Carrier Signal Quadrature Amplitude Modulation (QAM) 05 - Winter 2005 ECE ECE 766 Computer Interfacing and Protocols 3 Amplitude Shift Keying (ASK) Basic technique (like AM)  change the amplitude of the signal to transfer logical values On-Off/

##### Quiz 3 ANGEL->Lessons->Quizzes 1. Modulation and Demodulation 2.

(x) + mi ] * sin (35x) a = 0.3, mi =1 16 17 Modulation of Digital Signals A different term: shift keying – Instead of a continuum of possible values, digital shift keying has a fixed set Mapping to the power levels of a digital signal Amplitude Shift Keying: Example 18 Carrier: 2 sin(2  4 t) Digital input signal: Modulated carrier: 2V  level “1” 1V  level “0” Exercise: ASK Consider the/

##### Principles Of Communication Engineering

a square wave. 2-3: Sidebands and the Frequency Domain Figure 1-12: Amplitude modulation of a sine wave carrier by a pulse or rectangular wave is called amplitude-shift keying. (a) Fifty percent modulation. (b) One hundred percent modulation. 2-3: Sidebands and the Frequency Domain Pulse Modulation Continuous-wave (CW) transmission can be achieved by turning the carrier off and on, as in Morse code transmission/

##### Modulation                                                                 Digital data can be transmitted via an analog carrier signal by modulating one.

original value. If m= 1.0 then it varies by 100%. Modulation: Amplitude-Shift Keying (ASK) ASK encodes digital data by modulating the carriers amplitude between two or more levels. Suppose a signal with amplitude 1 represents a binary 0 and a signal with amplitude 2 represents a binary 1. AM is more sensitive to noise than other modulation techniques => AM is not widely used in data transmission .                                                                                A/

##### Chapter 2 Amplitude Modulation.

a square wave. 2-3: Sidebands and the Frequency Domain Figure 1-12: Amplitude modulation of a sine wave carrier by a pulse or rectangular wave is called amplitude-shift keying. (a) Fifty percent modulation. (b) One hundred percent modulation. 2-3: Sidebands and the Frequency Domain Pulse Modulation Continuous-wave (CW) transmission can be achieved by turning the carrier off and on, as in Morse code transmission/

##### REFERENCES CCRI Engineering and Technology Jbernardini 1 Introduction to Wireless Networking Module-5 Physical Layer Access Methods and Spread Spectrum.

, changes occur in discrete steps using binary signals – Uses same three basic types of modulation as Amplitude shift keying (ASK) REFERENCES CCRI Engineering and Technology Jbernardini 44 Frequency vs. Phase Shift Key Modulation CCRI Engineering and Technology Jbernardini 44 Frequency shift keying (FSK) Phase shift keying (PSK) REFERENCES CCRI Engineering and Technology Jbernardini 45 Throughput vs. Data Rate CCRI Engineering and Technology Jbernardini 45 Data Rate = Total Data Rate through system/

##### Chapter 2 Amplitude Modulation.

a square wave. 2-3: Sidebands and the Frequency Domain Figure 1-12: Amplitude modulation of a sine wave carrier by a pulse or rectangular wave is called amplitude-shift keying. (a) Fifty percent modulation. (b) One hundred percent modulation. 2-3: Sidebands and the Frequency Domain Pulse Modulation Continuous-wave (CW) transmission can be achieved by turning the carrier off and on, as in Morse code transmission/

##### Networking H15 Analog and Digital Data Data, Signal, Transmission Encoding and Decoding ( Amplitude Shift, Frequency Shift, PCM etc.) Transmission Simplex,

the carrier signal 8The receiving modem translates the analog signal back into digital data Methods of Modulation 8Amplitude modulation (AM) or amplitude shift keying (ASK) 8Frequency modulation (FM) or frequency shift keying (FSK) 8Phase modulation or phase shift keying (PSK) Amplitude Shift Keying (ASK) 8In radio transmission, known as amplitude modulation (AM) 8The amplitude (or height) of the sine wave varies to transmit the ones and zeros 8Major disadvantage is that telephone lines are very susceptible/

##### SUBELEMENT T8 Modulation modes: amateur satellite operation; operating activities; non-voice communications [4 Exam Questions - 4 Groups] 1Modes 2014.

plot at left T8A01 - Which of the following is a form of amplitude modulation? A. Spread-spectrum B. Packet radio C. Single sideband D. Phase shift keying 10Modes T8A01 - Which of the following is a form of amplitude modulation? A. Spread-spectrum B. Packet radio C. Single sideband D. Phase shift keying 11Modes T8A02 - What type of modulation is most commonly used for VHF packet radio transmissions? A. FM/

##### Signal Encoding, Spread Spectrum. Basic Encoding Techniques Digital data to analog signal Amplitude-shift keying (ASK) Amplitude difference of carrier.

signal Amplitude-shift keying (ASK) Amplitude difference of carrier frequency Frequency-shift keying (FSK) Frequency difference near carrier frequency Phase-shift keying (PSK) Phase of carrier signal shifted Basic Encoding Techniques Amplitude-Shift Keying One binary digit represented by presence of carrier, at constant amplitude Other binary digit represented by absence of carrier where the carrier signal is Acos(2πf c t) Amplitude-Shift Keying Susceptible to sudden gain changes Inefficient modulation/

##### 1 Combined Linear & Constant Envelope Modulation M-ary modulation: digital baseband data sent by varying RF carrier’s (i) envelope ( eg. MASK) (ii) phase.

M significantly higher BER - smaller distances in constellation - sensitive to timing jitter MPSK MQAM MFSK OFDM Combined Linear & Constant Envelope Modulation 3 Mary Phase Shift Keying Carrier phase takes 1 of M possible values – amplitude constant  i = 2(i-1)  /M, i = 1,2,…M Modulated waveform: s i (t) = 0  t  T s, i = 1,2,…M E s = log 2 M  E b/

##### 1 Digital to Analog Encoding. 2 3 Digital modulation techniques Amplitude Shift Keying Amplitude Shift Keying Frequency Shift Keying Frequency Shift.

1 Digital to Analog Encoding 2 3 Digital modulation techniques Amplitude Shift Keying Amplitude Shift Keying Frequency Shift Keying Frequency Shift Keying Phase Shift Keying Phase Shift Keying Quadrature Amplitude Modulation (QAM) Quadrature Amplitude Modulation (QAM) 4 Amplitude Shift Keying ASK ASK –The strength of carrier signal varies (the amplitude changes) –The frequency and phase remain constant –The speed of transmission is limited by the physical characteristics of the transmission media –/

##### Quadrature Amplitude Modulation Forrest Sedgwick UC Berkeley EECS Dept. EE290F October 2003.

removed from DC (like optical) is called a bandpass channel Transmission on a bandpass channel requires modulation of a carrier Amplitude Shift Keying (ASK) Phase Shift Keying (PSK) Frequency Shift Keying (FSK Quadrature Amplitude Modulation (QAM) Amplitude Shift Keying (ASK) Amplitude of carrier wave is modulated Equivalent BER vs SNR to baseband PAM Proakis and Salehi, pp. 306 Angle Modulation (PSK and FSK) Frequency is time derivative of phase, PSK and FSK are somewhat equivalent Proakis/

##### 5.1 Background Information Modulation Techniques (Chapter 5) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

.13 The total bandwidth required for PM can be determined from the bandwidth and maximum amplitude of the modulating signal: B PM = 2(1 + β)B. Note 5.14 Digital Modulation Digital modulation is used to generate analog signals from information bit streams Digital modulation types Amplitude Shift Keying Frequency Shift Keying Phase Shift Keying Quadrature Amplitude Modulation 5.15 Digital modulation is the process of changing one of the characteristics of an analog signal based/

##### Computer Networks Set 4: Media, Encoding and Modulation.

four zeros replaced with one or two pulses B8ZS and HDB3 Digital Data, Analog Signal ÑPublic telephone system Ñ300Hz to 3400Hz ÑUse modem (modulator-demodulator) ÑAmplitude shift keying (ASK) ÑFrequency shift keying (FSK) ÑPhase shift keying (PK) Modulation Techniques Amplitude Shift Keying ÑValues represented by different amplitudes of carrier ÑUsually, one amplitude is zero Ñi.e. presence and absence of carrier is used ÑSusceptible to sudden gain changes ÑInefficient ÑUp to 1200bps on voice/

##### Modulation and Transmitters

progress. Straight Key Keyer “Bug” Keyer Amplitude Modulation Changes the instantaneous power in the radio wave in time with a modulating signal. The strength (amplitude) of the carrier signal is made to vary in accordance with the audio signal. Modulation Envelope Audio /tones, corresponding to mark and space, are sent to the mic input when the radio is keyed. This is called Audio Frequency Shift Keying (AFSK), but is indistinguishable from FSK. RTTY Tuning Aid Packet Radio Computer to computer mode that/

##### Chapter Twelve: Digital Modulation and Modems. Introduction Digital signals have become very important in wired and wireless communications To send data.

have become very important in wired and wireless communications To send data by radio, higher frequency carrier waves are necessary Amplitude, frequency, and phase are all used in digital communication systems Frequency-Shift Keying The simplest form of digital modulation in current use is frequency-shift keying (FSK) In its simplest form two frequencies are generated, one corresponding to a binary zero (space) and the other/

##### An Najah National University Telecommunication Engineering Department comparison of binary shift keying techniques Prepeared by : Suhad Malayshi Raghad.

to that of Analogue transmission. Fundamental digital modulation methods: Binary Amplitude shift keying (on-off keying) advantage: simplicity disadvantage: ASK is very susceptible to noise interference– noise usually (only)affects the amplitude, therefore ASK is the modulation technique most affected by noise application: ASK is used to transmit digital data over optical fiber Frequency Shift Keying Frequency Shift Keying (FSK) is a frequency modulation scheme (conveys information over a carrier wave/

##### Rev.S08 MAC 1114 Module 4 Graphs of the Circular Functions.

Learning Objectives Upon completing this module, you should be able to: 1. Recognize periodic functions. 2. Determine the amplitude and period, when given the equation of a periodic function. 3. Find the phase shift and vertical shift, when given the equation /. Step 2: Sketch the two vertical asymptotes found. x =   /4. Step 3:Divide the interval into four equal parts. This gives the following key x-values.  First quarter: −  /8  Middle value: 0Third quarter:  /8 42 Rev.S08 How to Graph y = tan(2x)? /

##### Chapter 5 Radio Signals and Equipment Signal Review Modulation is the process by which information (voice or data) is impressed into the transmitted radio.

for AM, with or without modulation. The duty cycle for SSB is about 20 to 25% and 0% without modulation. Angle Modulated Modes –Frequency Modulation (FM) varies the frequency in proportion to the signals amplitude. –Phase modulation (PM) varies the phase (time shift) of the signal. –FM /the 5 bit Baudot code. On HF, most RTTY signals are 45 baud and use a 170 Hz shift between mark and space. Multiple-frequency shift keying (MFSK16) uses 16 separate tones separated by 15.625 Hz. This fits within a 500 Hz CW/

##### DATA COMMUNICATION Lecture-17. Recap of Lecture 16  Analog-To-Digital Conversion  Pulse Code Modulation (PCM) – Pulse Amplitude Modulation (PAM) – Quantization.

COMMUNICATION Lecture-17 Recap of Lecture 16  Analog-To-Digital Conversion  Pulse Code Modulation (PCM) – Pulse Amplitude Modulation (PAM) – Quantization – Binary Encoding – Digital-to-Digital Conversion Overview of Lecture 17  Digital-to Analog Conversion  Bit Rate and Baud Rate  Carrier Signals  Amplitude Shift Keying (ASK)  Frequency Shift Keying (FSK)  Phase Shift Keying (PSK)  Quadrature Amplitude Modulation (QAM) Digital To Analog Conversion  Process of changing one of the characteristics of/

##### Modulation Techniques for Mobile Radio

01 00 10 cos-sin -cos-sin CS 515 © Ibrahim Korpeoglu Constant Envelope Modulation Amplitude of the carrier is constant, regardless of the variation in the modulating signal Better immunity to fluctuations due to fading. Better random noise immunity Power efficient They occupy larger bandwidth CS 515 © Ibrahim Korpeoglu Frequency Shift Keying (FSK) The frequency of the carrier is changed according to the message state/

##### Amplitude Modulator and Demodulator Circuits

signal-to-noise ratio than standard diode detectors. 4-3: Amplitude Demodulators Synchronous Detection The key to making the synchronous detector work is to ensure that the /Amplitude Demodulators Figure 4-22 A practical synchronous detector. 4-4: Balanced Modulator A balanced modulator is a circuit that generates a DSB signal, suppressing the carrier and leaving only the sum and difference frequencies at the output. The output of a balanced modulator can be further processed by filters or phase-shifting/

##### Dr. Paramjeet Singh HoD,Dept. of CSE PTU GZS Campus Bathinda Subject: Computer Networks Topic: Encoding and modulating Punjab EDUSAT Society1.

Analog Encoding: Process of changing one of the characteristics of an analog signal based on the digital signal (1 or 0). It has following types: 1.Amplitude Shift Keying (ASK) 2.Frequency Shift Keying (FSK) 3.Phase Shift Keying (PSK) 4.Quadrature Amplitude Modulation (QAM) Punjab EDUSAT Society33 Punjab EDUSAT Society ASK: Strength of the carrier signal is varied to represent binary 1 or 0. 34 Bandwidth for ASK/

##### The Origin of Modems. Modems The word "modem" is a contraction of the words modulator-demodulator. A modem is typically used to send digital data over.

modems, modem designers had to use techniques far more sophisticated than frequency- shift keying. In order to create faster modems, modem designers had to use techniques far more sophisticated than frequency- shift keying. First they moved to phase-shift keying (PSK), and then quadrature amplitude modulation (QAM). First they moved to phase-shift keying (PSK), and then quadrature amplitude modulation (QAM). These techniques allow an incredible amount of information to be crammed/

##### COSC 3213 – Computer Networks I Summer 2003 Topics: 1. Line Coding (Digital Data, Digital Signals) 2. Digital Modulation (Digital Data, Analog Signals)

 01 B8ZS 14 Digital Data, Analog Signal – ASK (1) Amplitude Shift Keying (ASK): Information111 100 0 T 2T2T 3T3T 4T4T5T5T 6T6T ASK t 15 Digital Data, Analog Signal – FSK (2) Frequency Shift Keying (FSK): Information111 100 0 T 2T2T 3T3T 4T4T5T5T 6T6T ASK t /in a stereo system. How much data will be generated in one hour? 22 Analog Data, Digital Signals – Delta Modulation (1)  Delta modulation is a scheme used to improve the performance of PCM.  An analog signal is approximated by a staircase function /

##### Chapter 3 SignalsandEncoding/Modulating BY Mr.Sukchatri Prasomsuk.

(0 and 1). 64/78 Digital to Analog Modulation 3.9 Digital-to-Analog Conversion Types of digital-to-analog modulation 65/78 Digital-to-Analog Modulation ASKFSKPSK QAM 3.9 Digital-to-Analog Conversion ASK (Amplitude shift keying) : amplitude of carrier signal FSK (Frequency shift keying) : frequency of carrier signal PSK (Phase shift keying) : phase of the carrier signal QAM (Quadrature amplitude modulation): phase+amplitude Bit rate is the number of bits per/

##### Lecture 3 Paul Flynn Modulation. Frequency Spectrum.

Long Waves, Medium Waves and Short Waves Modulation of Analog Signals Amplitude Modulation (AM) Frequency Modulation (FM) Phase Modulation (PM) Figure 5.24 Analog-to-analog modulation Types of analog-to-analog modulation Amplitude modulation (AM) Frequency modulation (FM) Phase Modulation (PM) Digital modulation Three basic methods – Amplitude shift keying (ASK) – Frequency shift keying (FSK) – Phase shift keying (PSK Amplitude shift keying (ASK) Use different amplitude to represent 0 and 1. – Simple/

signals, PM is considered a special form of FM Difference is clearer in digital modulation process 8 Modulating Digital Signals Amplitude Shift Keying (ASK) Frequency Shift Keying (FSK) Phase Shift Keying (PSK) Combinations of the above 9 ASK and FSK Carrier Digital Input ASK FSK 10 Phase Shift Keying (PSK) 0 o phase shift180 o phase shift 11 PSK Constellation Diagrams Constellation diagram is used to express the exact assignment of data/

#####  We use the term modulation to refer to changes made in a carrier -according to the information being sent  Modulation takes two inputs -a carrier -and.

two inputs -a carrier -and a signal To distinguish between analog and digital modulation -We use the term shift keying rather than modulation  ASK is the abbreviation of Amplitude Shift Keying  Ask is called On-Off Keying.  The simplest and most common form of operate as a switch.  It is Abbreviated as Frequency shift keying  Values represented by different frequencies (near carrier)  Less susceptible to error than ASK  Typically used/

##### Principles of Electronic Communication Systems. Chapter 4 Amplitude Modulator and Demodulator Circuits.

signal-to-noise ratio than standard diode detectors. 4-3: Amplitude Demodulators Synchronous Detection The key to making the synchronous detector work is to ensure that the /Amplitude Demodulators Figure 4-22 A practical synchronous detector. 4-4: Balanced Modulator A balanced modulator is a circuit that generates a DSB signal, suppressing the carrier and leaving only the sum and difference frequencies at the output. The output of a balanced modulator can be further processed by filters or phase-shifting/

##### Chapter 21 Frequency Modulation GMSK Modulation

the non-linearities of the emitter or of the channel in mobile communications. They are also more robust to fading than modulation using the carrier amplitude to carry information. PSK = Phase Shift Keying OQPSK = Offset Phase Shift Keying 16QAM = QAM modulation with 16 different states For amplitude-phase. Spectral efficiency can be defined as the number of bits per second that can be transmitted in 1 Hz bandwidth/

##### Chapter 2: Digital Modulation

through a system in a given unit of time (bit rate  bps) Hartley’s Law Shannon limit for information capacity Amplitude-shift keying (ASK)  the binary information signal directly modulates the amplitude of an analog carrier  there are only two output amplitudes possible  mathematically written as Frequency-shift keying (FSK)  mathematically written as  when the binary input change logic from 1 to logic 0, the output frequency change/

##### Quiz #1 What is the difference between channel coding, modulation, and source coding? Draw a block diagram showing the order in which the following happens:

Sinusoid of frequency fc is centered in middle of bandpass channel Modulators embed information into a sinusoid Amplitude Modulation and Frequency Modulation Information 1 +1 Amplitude Shift Keying t T 2T 3T 4T 5T 6T -1 Map bits into amplitude of sinusoid: “1” send sinusoid; “0” no sinusoid Demodulator looks for signal vs. no signal +1 Frequency Shift Keying t T 2T 3T 4T 5T 6T -1 Map bits into/

##### SIGNAL MODULATION for MULTIMEDIA DATA TRANSMISSION

fc Use some combination of amplitude, phase, or frequency. MULTIMEDIA SYSTEMS IREK DEFEE Amplitude-Shift Keying (ASK) Change amplitude A CARRIER MULTIMEDIA SYSTEMS IREK DEFEE ASK (cont.) The signal is MULTIMEDIA SYSTEMS IREK DEFEE Phase-shift Keying (PSK) Change phase q /c@Irek Defée MULTIMEDIA SYSTEMS THERE ARE VERY MANY DETAILS IN ADSL STANDARD: HOW THE CARRIERS ARE MODULATED? (QAM MODULATION) HOW THE MODULATION IS REALIZED? (512-POINT FFT) HOW THE ERROR CORRECTION IS PERFORMED? (FEC) HOW THE SIGNALS /

##### Week 2 Things you want to know.

stability. Also, PM is adaptable to data applications Examples of Phase Shift Bit Rate = Baud rate x Bits per Symbol PSK and QAM Phase Shift Keying (PSK) Most popular implementation of PM for data In BPSK (Binary PSK): one bit per phase change In QPSK: two bits per phase change (symbol) Quadrature Amplitude Modulation (QAM) Uses two AM carriers with 90o phase angle between them/