SAULT COLLEGE OF APPLIED ARTS AND TECHNOLOGY

SAULT STE. MARIE, ONTARIO

COURSE OUTLINE

Course name: DIGITAL COMMUNICATIONS

Code No.: ELN 305-6

Program: ELECTRONIC TECHNOLOGY

Semester: SIX

Date: January 1994

Author: PETER SZILAGYI

Previous outline dated: August 1990

Approved:

Coordinator

Approved:

Date

Date

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Digital Communication ELN-305

Total credit hours 96

prerequisites ELN-245, ELR-309

I. PHILOSOPHY/GOALS

This course provides an in-depth frequency domain analysis of

analog and digital communications signals. Another objective is the

study of the widespread telephone network and the applications of

the most recent digital communications schemes.

II. STUDENT PERFORMANCE OBJECTIVES

Upon successful completion of this course, the student will be able to:

1. Perform the spectral analysis of arbitrary waveforms and

operate a radio frequency spectrum analyzer.

2. Understand the concept of frequency division and time division

mul tiplexing of voice signals, and the essentials of data

communication concepts.

3. Apply the principles of analog pulse modulation and digital

modulation to simplex, duplex and multi-channel communication

systems.

4. Understand the terminology and principles of information

theory.

Digital Communication ELN-305

III. TOPICS TO BE COVERED

1. Voice and data communication.

2. Spectral analysis.

3. Pulse and digital modulation.

4. Information theory.

IV. LEARNING ACTIVITIES

BLOCK 1: VOICE AND DATACOMMUNICATION OVER ANALOGSYSTEMS

Upon successful completion ofthis unit, the student will beable to:

1.1 Recall and be familiarwith:

the block diagram of a basiccommunication system.psophometric and C-messageweighting curves.the characteristics andbandwidth of voice.FDM and TDM concepts.Simplex and Duplexcommunication.

1.2 Have a good understandingof the:

telephone network.the 500 type telephone set.DTMF telephones.subscriber to trunk circuitinterfacing.touch tone decoders.characteristic impedance andpropagation constant.standard CCITT groups.types of trunk circuits.concepts of centralizedswitching.four wire terminating set.network stability, noise,distortion, crosstalk.group delay, delayequalizers, dynamiccompandors.

REQUIRED RESOURCES

TEXT: Digital, Analog, andData Communication.

ACTIVITIES:

Study pp. 1-38, Chapter 1.

Solve problems 1 to 30.

Study pp. 42-104,Chapter 2.

Solve problems 1 to 20.

Study pp.106-141,Chapter 3.Solve problems 1 to 19.

1.3 Recall and understand DataCommunication concepts, asfollows:

- the Seven-Layer OSIarchitecture.

- RS-232-C, RS-422-A, RS-423-A,RS-449 interface standards.the "bit rate = baud rate xbits per baud".calculate the Information

Rate = (lIT) log2n for nbits.

- balanced and unbalanced linesand generators.

- differential and unbalancedreceivers.

20 mA current-loopinterfaces.- 8251 USART.

1.4 Recall and understand theessentials of MODEM theory:

line losses caused by skineffect, proximity effect andradiation.line drivers, limiteddistance modem and modemeliminator.

modem modulation techniques:ASK, FSK, PSK, DPSK, QAM.CCITT and Bell standardmodems.frequency spectrum of FSK andPSK modems.FSK, BPSK, DPSK andFour-Phase modulators and

demodulators.phasor diagram of modemsignals.

BLOCK 2: SPECTRAL ANALYSIS

Upon successful completion ofthis unit, the student will beable to:

2.1 Write the mathematicalform of time functions ofelectric waves or electronicsignals such as: square wave,rectangular pulses, sawtooth,AM, SSB, FM signals, etc.

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Study pp.144-172,Chapter 4.

Solve problems 1 to 57.

Study pp.181-211,Chapter 5.

Solve problems 1 to 28, 39to 42, 44 to 46, 55 to 57,72.

TEXT:Network15 andteacher.

Van Valkenburg,Analysis, Chapter16, provided by

ACTIVITIES:

Study pp. 452-513. Selectedproblems will be assigned.

2.2 Recall the definition orthe applicationof:

periodic functions.odd and even functions.Dirichlet conditions.Fourier series.truncated series.amplitude and phase spectrum.the sin/cos form, theamplitude-phase form and theexponential form of theFourier series.the (sin x)/x function.

2.3 Calculate theseries coefficientsform of the series.

Fourierfor each

amplitude and(Single sided

2.4 Plot thephase spectra.and two sided).

2.5 Sketch the spectrumenvelope for recurring pulses.

2.6 Generate the waveform of asignal from the Fourier series.

BLOCK 3: PULSE AND DIGITALMODULATION

3.1 Recall the principles ofAnalog Pulse Modulation:

- time sampling and samplingtheorem.

natural and flat-top (sampleand hold) sampling.aliasing and aperturedistortion.Chebyschev, Butterworth,Bessel and Cauer filtercharacteristics.Time Division Multiplexing ofPAM signals.PAM-TDM System block diagramand waveforms.PAM, PDM and PPM modulatorsand demodulators.Pulse Edges Only modulators.

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Use MathCad to solveFourier analysis problems.

TEXT: Digital, Analog, andData Communication.

ACTIVITIES:

Study pp.268-298,Chapter 6.

Solve problems 1 to 14.

3.2 Be able to mathematicallyinterpret the sampling theorem,and

observe that the sampledwaveform can be expressedas:

Sam(t)=m(t).S(t)

multiply the Fourier seriesexpansion of the samplingfunction by the frequencyspectrum of the message, toobtain the frequencyspectrum of the sampledmessage.plot the line spectrum of theswitching function.plot the frequency spectrumof the natural sampledwaveform.

plot the frequency spectrumof a sample-and-hold signal.plot the frequency spectrumof a single pulse.calculate the aperture time.

3.3 Recall the applications,definition and properties oftwo of the most common type ofDigital Modulation: CVSD andPCM.

sketch the block diagram andexplain the functioning of adelta encoder and decoder.given the maximum rate ofrise of a signal, and thestep size a, calculate themaximum amplitude timesmodulating frequency product:A-fm = a.fs/2nunderstand slope overload,tracking and idlingconditions of a deltamodulator.recall the functions of aPCM: sampling, quantizing andencoding.understand the block diagramof a PCM terminal.calculate the S/N ratio of asignal encoded by an 8 bitcode.

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TEXT: Digital, Analog, andData communication.

Study pp.301-348,Chapter 7.Solve problems 1 to 37.

for a message with a maximumrate of change and for amaximum aperture uncertainty"a", calculate the maximumaperture time of the AIDconverter: n

1: = 1 I (2 -1) nf

understand and apply the plaw.be able to determine the 8bit code of a sample of themessage.be able to decode the signalY from the digit pattern.recall the functioning ofparallel, serial and hybridencoders and the weightedcurrent source and ladderdecoders.explain the advantage of themonolithic integrated circuitCODECsketch and explainqualitatively a 24 channelPCM system frame alignmentand time slot assignment.recall the types of linecoding: RZ, NRZ, AMI,unipolar and polar.justify the bandwidthrequirements of the aboveline codes.recall and be able tocalculate the fundamentalfrequency of a 24 channel PCMsystem, using RZ unipolarcode.recall the North American PCMmultiplex hierarchies.draw the block diagram of aquantization noisemeasurement system.

BLOCK 4: INFORMATION THEORY

4.1 Apply the principles ofInformation Theory, as follows:

recall that the basic unit ofinformation is the bit.

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ACTIVITIES:

Study the specificationsof the INTEL 2910A Codec.INTEL documentationavailable in thelaboratory.

be able to calculate theinformation content for n

alternatives: H = log2mrecall that the informationcontent varies directly withthe message length: n

H = log2mcalculate the informationcapacity from the informationcontent over a time period,as

recall that the number ofpulses transmitted persecond, relate linearly tothe bandwidth, expressed asC = 2-BW-log2m

4.2 Analyze pulse transmissionover bandlimited systems:

be able to interpret theFourier series of a pulsetrain.graphically show the effectof filtering on a periodicbit stream.

3.3 Understand coding forcommunications.

recall the essentials of theBCD, EBCDIC, ASCI I, HOLLERITHand NUMERIC codes.recall the two basic errorcontrol methods:retransmission andforward acting.use geometrical models toillustrate the Hammingdistance.

recall the error detectingmechanism of Cyclic andHamming codes.graphically represent theline spectra of typical linecodes: RZ, NRZ, AMI, HDB3.recall that Manchester codinguses the phase of a squarewave and collisions aredetected by monitoring the dccomponent.

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TEXT: Analog, Digital, andData Communication.

ACTIVITIES: Selectedtopics from Chapter 8, 9,and 10 will be presented.

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Digital Communication ELN-305

V. ADMINISTRATIVE AND EVALUATION PROCEDURES

TESTING

a) Written tests based upon theory objectives will occurfollowing the completion of each theory block and with abouta week of advance notice. Short written quizzes may occur atany time without advance notice

Testing of lab objectives will occur concurrent with thespecific lab activity.

b)

GRADING

a) Grading is done using the followingdefinitions:Consistentlyoutstandingperformance A+ (90Outstandingperformance A (80Above averageperformance B (70Satisfactoryperformance C (55Unsatisfactoryperformance R (0

-100)%90)%80)%70)%55)%

b) The grading of laboratory type objectives will be in twoparts: The demonstrated ability to perform a skill function,e.g. use an instrument in a specified role or trouble shoota circuit, will be graded "C". Failure to demonstrate the~kill function will be graded "R". Subjective evaluation oflab reports, supporting theory, deportment, housekeepingetc., will be used to modify the skill function grade upward,where applicable.

c) Lab reports are due one week after the experiment wasscheduled to be completed. Late reports are penalized 5% perday.

d) The grading weight will be 30% for the lab and 70% for thetheory.

e) A final overall accumulated mark of 55% is the minimumrequirement for course credit with the added restriction thatneither the theory or the lab part of the course can be lessthen 55%. e) A failing grade on more then half of the theorytests during the semester leads directly to an "R" grade,regardless of the theory average.

f) Failing one third of the semesters theory tests excludes afinal "A" grade, regardless the theory average.

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Digital Communication ELN-305

UPGRADING

a) No upgrading tests will take place during the semester.

b) The method of upgrading is at the teachers discretion. Itmay consist of the rewriting of block tests, the writing ofcomprehensive examination, repeating laboratory experimentsor repeating the course.

c) The highest mark obtainable in any make-up test is"Sufficient".

ATTENDANCE

a) Attendance for laboratory classes is compulsory.

b) Attendance at all theory classes will be recorded.Attendance is highly recommended but not mandatory.

c) Anyone with an accumulated attendance record of less then 80%at the end of the semester, and who is also in a failingcondition, can expect to have to repeat the course, with noright to write a make-up test.