Virginia Tech® home

ECE 4634 - Digital Communications (3C)

Course Description

System and signal level analysis and design for digital communications systems. Review of analog-to-digital conversion and digital baseband communications. Detailed analysis of digital carrier modulation formats including assessment of signal-to-noise ratio, bit error rate, and power and bandwidth efficiency for amplitude-shift keying (ASK), phase-shift keying (PSK), frequency-shift keying (FSK), and Quadrature-Amplitude Modulation (QAM). Matched filter receivers and receiver design, link budgets, and multiple access. Additive-white-noise Gaussian channels. A detailed discussion of random variables will be included to supplement prerequisite material.

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 for advanced study of digital communications systems, and the skills acquired in this course are fundamental for employment in the rapidly growing communications industry.

Learning Objectives

  • 1. Design digital communication systems (e.g., choose modulation scheme, coherent vs. non-coherent), given constraints on data rate, bandwidth, power, and bit error rate;
  • 2. 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.
  • 3. Compute the power and bandwidth requirements of modern communication systems, including those employing Amplitude-Shift Keying (ASK), Phase-Shift Keying (PSK), Frequency-Shift Keying (FSK), and Quadrature-Amplitude Modulation (QAM) modulation formats;
  • 4. Determine the auto-correlation function of a line code and determine its power spectral density (PSD);
  • 5. Determine the power spectral density of bandpass digital modulation formats.

    • Resources & Links

    Two-Semester Major Design Experience

    ECE’s two-semester Major Design Experience (ECE 4805-4806) provides teams of students with simulations of the post-college world via projects specified and directed by industry partners. For more information, contact class instructor, Dr. Joe Adams.

    Textbook List

    Take a look at the Fall 2024 ECE textbook list.
    Take a look at the Spring 2025 ECE textbook list.

    Current Prerequisites & Course Offering

    For current prerequisites for a particular course, and to view course offerings for a particular semester, see the Virginia Tech Course Timetables

    ABET Engineering Accreditation Commission

    The B.S. degree in electrical engineering and the B.S. degree in computer engineering are accredited by the Engineering Accreditation Commission of ABET.

    Program Educational Objectives (PEOs) & Student Outcomes (SOs)