Data Communication and Networks Lecture 2a Data Transmission and Encoding Concepts September 15, 2005.

Slides:



Advertisements
Similar presentations
Physical Layer: Signals, Capacity, and Coding
Advertisements

Teknik Enkoding Pertemuan 08 Matakuliah: H0484/Jaringan Komputer Tahun: 2007.
Data and Computer Communications Eighth Edition by William Stallings Lecture slides by Lawrie Brown Chapter 5 – Signal Encoding Techniques.
Data and Computer Communications
Data and Computer Communications Chapter 5 – Signal Encoding Techniques.
1 Data Encoding – Chapter 5 (part 1) CSE 3213 Fall /2/2015 9:13 AM.
Chapter 5 – Signal Encoding and Modulation Techniques
ECE 4321: Computer Networks Chapter 3 Data Transmission.
William Stallings Data and Computer Communications Chapter 5 Data Encoding.
William Stallings Data and Computer Communications 7 th Edition Chapter 3 Data Transmission.
EE 4272Spring, 2003 Chapter 5 Data Encoding Data Transmission Digital data, digital signal Analog data, digital signal: e.g., voice, and video are often.
IRAN UNIVERSITY OF SCIENCE AND TECHNOLOGY Computer department Chapter 3 Data Transmission Ahmad AKBARI Assistant Prof Spring 2002.
4.2 Digital Transmission Pulse Modulation (Part 2.1)
1 CSC 535 Communication Networks I Appendix 3A Asynchronous Communications Dr. Cheer-Sun Yang.
EE 4272Spring, 2003 Chapter 3 Data Transmission Part II Data Communications Concept & Terminology Signal : Time Domain & Frequency Domain Concepts Signal.
Chapter 3 Data and Signals
William Stallings Data and Computer Communications 7th Edition
Data Communication and Networks Lecture 2a Data Transmission and Encoding Concepts September 11, 2003 Joseph Conron Computer Science Department New York.
COE 342: Data & Computer Communications (T042) Dr. Marwan Abu-Amara Chapter 6: Digital Data Communications Techniques.
1 Physical Layer: Data Encoding & Transmission. 2 Network Interface Card (NIC) LL in part, PL in total are implemented in NIC –Ethernet card, card,
William Stallings Data and Computer Communications 7th Edition (Selected slides used for lectures at Bina Nusantara University) Data, Signal.
Module 3.0: Data Transmission
Signal Encoding Lesson 05 NETS2150/2850
Data and Computer Communications Lecture 2 Data Transmission.
The Physical Layer, Encoding Schemes: -Physical Transmission of Bits- Chapter 2.
Data Communications Chapter 6 The Data Communications Interface.
William Stallings Data and Computer Communications Chapter 6 The Data Communications Interface.
William Stallings Data and Computer Communications Chapter 3 Data Transmission.
331: STUDY DATA COMMUNICATIONS AND NETWORKS.  1. Discuss computer networks (5 hrs)  2. Discuss data communications (15 hrs)
LECTURE 5 CT1303 LAN. DATA ENCODING Digital signal: is a sequence of discrete, discontinuous voltage pulses. Each pulse is a signal element Binary data.
Lecture slides prepared for “Business Data Communications”, 7/e, by William Stallings and Tom Case, Chapter 5 “Data Communication Fundamentals”.
DIGITAL-TO-DIGITAL CONVERSION
Base-Band Digital Data Transmission Prepared By: Amit Degada. Electronics Engineering Department, Sardar Vallabhbhai National Institute of Technology,
Aegis School of Telecommunication Telecom Systems I by Dr. M. G. Sharma, Phd. IIT Kharagpur Microwaves and Antennas.
CSC535 Communication Networks I Chapter 3a: Data Transmission Fundamentals Dr. Cheer-Sun Yang.
1 Business Telecommunications Data and Computer Communications Chapter 3 Data Transmission.
CE 4228 Data Communications and Networking
Data Communications Chapter 5 Data Encoding.
© Janice Regan, CMPT 128, CMPT 371 Data Communications and Networking Digital Encoding.
Data Encoding Reading Assignment : Stallings Chapter 2, pp , Chapter 4, pp , , Terminology –Data entities that convey.
ECS 152A 4. Communications Techniques. Asynchronous and Synchronous Transmission Timing problems require a mechanism to synchronize the transmitter and.
Data Communication and Networks Lecture 2 Data Transmission and Encoding Concepts September 12, 2002 Joseph Conron Computer Science Department New York.
Aegis School of Telecommunication 1 Telecom Systems I by Dr. M. G. Sharma, Phd. IIT Kharagpur Microwaves and Antennas Dean Telecom.
1 William Stallings Data and Computer Communications Chapter 5 Data Encoding.
EEC4113 Data Communication & Multimedia System Chapter 2: Baseband Encoding by Muhazam Mustapha, July 2010.
CSC 335 Data Communications and Networking
Prof. Hosny Ibrahim Lecture 5. Data Communication IT 221 By: Prof. Hosny M. Ibrahim 2.
Session 2. Objectives: By the end of this session, the student will be able to: Distinguish between data and signals. Cite the advantages of digital data.
CSCI 465 Data Communications and Networks Lecture 8 Martin van Bommel CSCI 465 Data Communications and Networks 1.
1 Business Telecommunications Data and Computer Communications Chapter 6 The Data Communications Interface.
Digital Line Encoding Converting standard logic level to a form more suitable to telephone line transmission. Six factors must be considered when selecting.
Signal Encoding Techniques Ir. Hary Nugroho MT.. Data Transmission.
Data and Computer Communications Tenth Edition by William Stallings Data and Computer Communications, Tenth Edition by William Stallings, (c) Pearson Education,
Signal Encoding Techniques. Digital Data, Digital Signal  Digital signal discrete, discontinuous voltage pulses discrete, discontinuous voltage pulses.
William Stallings Data and Computer Communications Chapter 6 The Data Communications Interface.
CSE 320 Data Communications
Data Encoding Data Encoding refers the various techniques of impressing data (0,1) or information on an electrical, electromagnetic or optical signal that.
William Stallings Data and Computer Communications
4.2 Digital Transmission Pulse Modulation (Part 2.1)
DIGITAL TRANSMISSION PART C
William Stallings Data and Computer Communications 7th Edition
Pemrosesan Data Tersebar
Chapter 4 Digital Transmission
Data Encoding Data Encoding refers the various techniques of impressing data (0,1) or information on an electrical, electromagnetic or optical signal that.
NET301 Lecture 5 10/18/2015 Lect5 NET301.
NET301 Lecture 5 10/18/2015 Lect5 NET301.
Chapter 4 Digital Transmission
EEC4113 Data Communication & Multimedia System Chapter 2: Baseband Encoding by Muhazam Mustapha, September 2012.
William Stallings Data and Computer Communications
Presentation transcript:

Data Communication and Networks Lecture 2a Data Transmission and Encoding Concepts September 15, 2005

Simplified Data Communications Model

Terminology (1) zTransmitter zReceiver zMedium yGuided medium xe.g. twisted pair, optical fiber yUnguided medium xe.g. air, water, vacuum

Terminology (2) zDirect link yNo intermediate devices zPoint-to-point yDirect link yOnly 2 devices share link zMulti-point yMore than two devices share the link

Terminology (3) zSimplex yOne direction xe.g. Television zHalf duplex yEither direction, but only one way at a time xe.g. police radio zFull duplex yBoth directions at the same time xe.g. telephone

Analog and Digital Data Transmission zData yEntities that convey meaning zSignals yElectric or electromagnetic representations of data zTransmission yCommunication of data by propagation and processing of signals

Data zAnalog yContinuous values within some interval ye.g. sound, video zDigital yDiscrete values ye.g. text, integers

Signals zMeans by which data are propagated zAnalog yContinuously variable yVarious media xwire, fiber optic, space ySpeech bandwidth 100Hz to 7kHz yTelephone bandwidth 300Hz to 3400Hz yVideo bandwidth 4MHz zDigital yUse two DC components

Data and Signals zUsually use digital signals for digital data and analog signals for analog data zCan use analog signal to carry digital data yModem zCan use digital signal to carry analog data yCompact Disc audio

Analog Transmission zAnalog signal transmitted without regard to content zMay be analog or digital data zAttenuated over distance zUse amplifiers to boost signal zAlso amplifies noise

Digital Transmission zConcerned with content zIntegrity endangered by noise, attenuation etc. zRepeaters used zRepeater receives signal zExtracts bit pattern zRetransmits zAttenuation is overcome zNoise is not amplified

Advantages & Disadvantages of Digital zCheaper zLess susceptible to noise zGreater attenuation yPulses become rounded and smaller yLeads to loss of information

Attenuation of Digital Signals

Interpreting Signals zNeed to know yTiming of bits - when they start and end ySignal levels zFactors affecting successful interpreting of signals ySignal to noise ratio yData rate yBandwidth

Encoding Schemes zNonreturn to Zero-Level (NRZ-L) zNonreturn to Zero Inverted (NRZI) zBipolar -AMI zPseudoternary zManchester zDifferential Manchester zB8ZS zHDB3

Nonreturn to Zero-Level (NRZ-L) zTwo different voltages for 0 and 1 bits zVoltage constant during bit interval yno transition I.e. no return to zero voltage ze.g. Absence of voltage for zero, constant positive voltage for one zMore often, negative voltage for one value and positive for the other zThis is NRZ-L

Nonreturn to Zero Inverted zNonreturn to zero inverted on ones zConstant voltage pulse for duration of bit zData encoded as presence or absence of signal transition at beginning of bit time zTransition (low to high or high to low) denotes a binary 1 zNo transition denotes binary 0 zAn example of differential encoding

NRZ

Differential Encoding zData represented by changes rather than levels zMore reliable detection of transition rather than level zIn complex transmission layouts it is easy to lose sense of polarity

NRZ pros and cons zPros yEasy to engineer yMake good use of bandwidth zCons ydc component yLack of synchronization capability zUsed for magnetic recording zNot often used for signal transmission

Biphase zManchester yTransition in middle of each bit period yTransition serves as clock and data yLow to high represents one yHigh to low represents zero yUsed by IEEE zDifferential Manchester yMidbit transition is clocking only yTransition at start of a bit period represents zero yNo transition at start of a bit period represents one yNote: this is a differential encoding scheme yUsed by IEEE 802.5

Biphase Pros and Cons zCon yAt least one transition per bit time and possibly two yMaximum modulation rate is twice NRZ yRequires more bandwidth zPros ySynchronization on mid bit transition (self clocking) yNo dc component yError detection xAbsence of expected transition

Asynchronous and Synchronous Transmission zTiming problems require a mechanism to synchronize the transmitter and receiver zTwo solutions yAsynchronous ySynchronous

Asynchronous zData transmitted on character at a time y5 to 8 bits zTiming only needs maintaining within each character zResync with each character

Asynchronous (diagram)

Asynchronous - Behavior zIn a steady stream, interval between characters is uniform (length of stop element) zIn idle state, receiver looks for transition 1 to 0 zThen samples next seven intervals (char length) zThen looks for next 1 to 0 for next char zSimple zCheap zOverhead of 2 or 3 bits per char (~20%) zGood for data with large gaps (keyboard)

Synchronous - Bit Level zBlock of data transmitted without start or stop bits zClocks must be synchronized zCan use separate clock line yGood over short distances ySubject to impairments zEmbed clock signal in data yManchester encoding yCarrier frequency (analog)

Synchronous - Block Level zNeed to indicate start and end of block zUse preamble and postamble ye.g. series of SYN (hex 16) characters ye.g. block of patterns ending in zMore efficient (lower overhead) than async

Synchronous (diagram)