ECEN 4652/5002, Communications Lab

ECEN 4652/5002 - Communications Lab

Peter Mathys, Spring 2013

Course Description and Requirements

Class: W 3:00-4:15 am, ECEE 265
Lab: T 3:00-4:50 pm and open lab times, ECEE 287
Instructor: Professor Peter Mathys, ECEE 1B67, 303-492-7733, Fax: 303-492-2758, e-mail:
Office Hours: MWF 1-3 pm, and by appointment.

Text: Experiment descriptions will be posted at http://ecee.colorado.edu/~mathys/ecen4652

Pre/Corequisite: ECEN 4242, Communication Theory
Credit Hours: 3

Description: The essence of any communication system is the generation and reliable detection of signals which carry information over a noisy channel with bandwidth and power limitations. A distinction is usually made between analog and digital communication systems, depending on whether the transmitted information is in digital or analog form. Most physical channels, such as wires, optical fibers or free-space electromagnetic wave propagation are analog in nature and must use waveforms (which are continuous in time and amplitude) at their inputs and outputs. Increasingly, however, digital signal processing (DSP) is used to produce these waveforms at the transmitter and to process them at the receiver. There are several reasons for this. First and foremost the use of programmable digital hardware is cheaper because the same hardware design can be used with different software to implement many different communication systems. Moreover, no costly adjustments due to tolerances and aging of analog components are needed. Second, such parameters as the response of filters, the bandwidth of the generated waveforms and the phase and frequency stability of oscillators can be controlled much more precisely in a digital environment. Third, sophisticated algorithms for synchronization, data compression, cryptography, and error control coding can be implemented quite easily using intelligent digital signal processing hard- and software.

This laboratory course is an introduction to the most common techniques that are used to build both analog and digital communication systems using a modern digital signal processing approach. Digital communication systems are introduced by looking first at baseband transmission methods such as pulse amplitude modulation (PAM), partial response (PR) signaling, and pulse code modulation (PCM). Next, using amplitude modulation (AM), several aspects and implementation issues of moving the spectrum of an analog or digital baseband signal to the passband of a transmission channel and back at the transmitter and receiver are discussed. Many of these techniques are then shown to be useful as well in the context of phase and frequency modulation (PM and FM). The combination of AM, FM, PM and PAM or PCM finally leads to the most commonly used digital modulation systems such as frequency shift keying (FSK), phase shift keying (PSK) and more general 2-dimensional signal constellations using quadrature amplitude modulation (QAM). In the majority of cases the goal of a communication system is to transmit information reliably as fast as possible within a given channel bandwidth and power constraint. A different approach, which will be studied towards the end of the semester, is called spread spectrum communication. As the name indicates, the spectrum of the information signal is spread out over a large range in such systems. This is advantageous to combat intentional and unintentional jamming between many users who share a common portion of the radio frequency spectrum.

Course Coverage:
1. Matlab Refresher, Representation of Signals in the Time Domain, Power and Energy
2. Review of Fourier Transforms, Power Spectral Density, Filters
3. Sampling Theorem, Pulse Amplitude Modulation (PAM), Pulse Code Modulation (PCM)
4. Nyquist's Criterion, Intersymbol Interference (ISI), Eye Diagrams, Bit Error Rate (BER)
5. Clock Extraction, Time Division Multiplexing (TDM)
6. Partial Response (PR) Signaling, Maximum Likelihood (ML) Sequence Detection Using Viterbi Algorithm
7. Double Sideband (DSB) Amplitude Modulation (AM) with Suppressed or Transmitted Carrier (SC or TC), Coherent and Non-Coherent Receivers
8. Frequency Division Multiplexing (FDM), Mixers, Superheterodyne Receivers
9. Quadrature Amplitude Modulation (QAM), Complex Lowpass Signals, Single Sideband (SSB) AM
10. Binary and Quaternary Phase Shift Keying (BPSK and QPSK), QAM Signal Constellations
11. Phase and Frequency Modulation (PM and FM), Narrowband FM, Frequency Shift Keying (FSK)

Course Requirements:
1. Attend class.
2. Lab Experiments (60%): Weekly, lab reports are due on Wednesdays 11:59 pm in D2L dropbox.
  Note: The lab experiments and the lab reports are individual efforts!
3. Peer grading of lab reports (20%).
4. Quizzes (20%): Approximately bi-weekly, on material covered in class and/or labs.

Note: All lab reports are individual efforts! Identical copies of reports, parts of reports, and Matlab files will not be accepted.
Click here for the Lab Report Format

Course Goal: Learn how to generate and process analog and digital communication signals using digital signal processing algorithms. Observe and interpret the impact of channel impairments such as noise, power limitation and finite bandwith on different communication methods and signals.