EE 313 Linear Systems and Signals - Lecture 3

Lecture by Prof. Brian L. Evans

Before Lecture

"Roll the Bones", Shakey Graves, 2011.
Tremolo. The Smiths, "How Soon is Now?", opening guitar riff has a tremolo effect by guitarist Johnny Marr, with a second voice playing slide guitar. Tremolo is rapid change in volume to give a sensation of motion, and is rapidly varying modulation effect. "Songs that Changed Music: The Smiths - How Soon Is Now".
History of Electronic Music", StomperYoshi, 2013.

Announcements

Homework #2 is due by 11:59pm on Friday, Sept. 12, 2025, by submission on Gradescope.

Lecture

Lecture slides on Fourier Series in PowerPoint format.
- Notes for Part 1 in Word and PDF formats
- Notes for Part 2 in Word and PDF formats

Supplemental Material

Fall 2024
- Sum of 440 660 740 Hz part 1 and part 2
- Harmonic frequencies
- Simplifying the square of a cosine signal
- Simplifying exp(-j pi k)
Fall 2023
- Fall 2023 Part 1
  - Board. Tremolo effect as heard on the song by The Smiths
  - Doc Cam. Beat frequencies of 10 and 1000 Hz
  - Board. Cosine squared has two non-negative frequencies: 0 Hz and twice the cosine frequency
  - Doc Cam. Derivation of Fourier series of cosine squared
  - Board. Beat frequencies of f0-f1 and f0+f1 arise when cos(2 pi f0 t) is multiplied by cos(2 pi f1 t)
- Fall 2023 Part 2
- Derivation of the Fourier series
Fall 2021: Modulation Property, Sinusoid in time and frequency, Fourier Series
Fall 2017 audio recording of the presentation on Sept. 14, 2017, of slides 3-7 to 4-4 in MP3 format.

Last updated 09/12/25. Send comments to Prof. Evans at bevans@ece.utexas.edu