ECE 4634 Digital Communications | ECE | Virginia Tech

Undergraduate PROGRAMS

Course Information


System level analysis and design for digital communications systems: analog-to-digital conversion, digital baseband communications, carrier modulation formats, matched filters, bandwidth efficiency, receiver design, link budgets, signal-to-noise ratio, bit error rattes in additive-white-noise Gaussian (AWGN) channels, and multiple access. Pre: 3614, STAT 4714. A grade of C- or better is required in these prerequisites.

Why take this course?

The course introduces students to the fundamentals of system level design and analysis of digital communications systems. This material is necessary introductory material for advanced study of digital communications systems, and the skills acquired in this course are fundamental for employment in the rapidly growing communications industry. The course provides fundamental material applicable to military communications, cellular telephone, satellite communications, telecommunications networks, and wireless data networks.

Learning Objectives

  • Design digital communication systems, given constraints on data rate, bandwidth, power, fidelity, and complexity;
  • Analyze the performance of a digital communication link when additive noise is present in terms of the signal-to-noise ratio and bit error rate;
  • Compute the power and bandwidth requirements of modern communication systems, including those employing ASK, PSK, FSK, and QAM modulation formats;
  • Design a scalar quantizer for a given source with a required fidelity and determine the resulting data rate;
  • Determine the auto-correlation function of a line code and determine its power spectral density;
  • Determine the power spectral density of bandpass digital modulation formats.

Course Topics


Percentage of Course

1. Review of basic signal and noise theory, modulation, spectra 10%
2. Digital Communications: 0%
a. Digital Baseband Signaling 5%
b. Analog-to-Digital Conversion 10%
c. Digital Bandpass Modulation 15%
d. Signal Space Representation 15%
3. Effect of noise on communication systems: 0%
a. Review of probability theory 5%
b. Properties and representation of noise 5%
c. Matched filter receivers 5%
d. Signal to noise ratio 5%
e. Bit error rate in digital links 15%
f. Bandwidth/performance trade-off 5%
g. Symbol/frequency acquisition and tracking 5%