ECE 445S Real-Time Digital Signal Processing Laboratory - Lecture 8

Announcements: Setting the Stage

Lecture

• Example tradeoffs in sampling rate and amplitude resolution for analog-to-digital converters a.k.a. digitizers:
  

  Analog-to-Digital Converter	Channels	Bits/sample	Sampling rate	Signal Bandwidth
  NI PXIe-5186	2	8	12.5 GSPS	5 GHz
  NI PXI-5154	2	8	2 GSPS	1 GHz
  NI PXIe-5122	1	14	100 MSPS
  NI PXI-5192	1	16	15 MSPS
  NI PXI-5192	1	24	500 KSPS

• Lecture 8 slides on Quantization in PowerPoint format.
  • Quantization occurs in stages (one bit per stage)
  • Signal to quantization noise ratio (SQNR)
  • A/D conversion of a signal plus additive thermal noise

• Fall 2020 lecture notes by Mr. Jacobellis and Prof. Evans

• Lab 7 preview on audio delay effects
  • Reverb and Delay Explained by Stella
  • Delay controls when the echoes arrive
  • Reverb consists of delays not controlled (e.g. echoes in a room)
  • FIR and IIR filters

• Songs
  • Chris Isaak, "Wicked Games", an example of vibrato effort using a guitar whammy bar. Vibrato is a slowly varying modulation effect.
  • 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".
  • Post Malone, "Circles", demonstrating use of delay, chorusing, and reverb in the vocals, and delay and reverb in the instruments. "Vocal Effects of Post Malone - Circles".

• Lecture on Quantization in spring 2014 on Video: Part 1 - Part 2

Supplemental Information

• Fall 2022 marker board notes on Data converter tradeoffs in signal quality vs. power consumption
• Spring 2022 marker board notes on mid-rise quantizers
• Fall 2021 marker board notes
  • Quantization in the receiver decision device
  • Thermal and quantization noise
• Zhuo Wang, Jintao Zhang and Naveen Verma, "Reducing Quantization Errors for Inner-Product Operations in Embedded Digital Signal Processing Systems", IEEE Signal Processing Magazine, Nov. 2016, pp. 141-147.
  • Evaluate energy-precision tradeoffs for new floating-point format used in FIR filtering
  • Use in FIR filters to analyze electroencephalogram (EEG) data to detect seizures
• Audio Effect Tutorials
  • Stella, Reverb and Delay Explained, start at 1:11 mark. Delay controls when the echoes arrive, whereas reverb consists of delays that are not controlled.
  • Johnny DeMarco, "EFFECTS 101: Delay", effects of feedforward and feedback delay
  • Johnny DeMarco, "EFFECTS 101: Chorus", use of feedforward delays to make one voice sound like many
  • Johnny DeMarco, "EFFECTS 101: Reverb", reverb (resonant sound from a large room)
  • Danilo Vicari, "Top 10 DELAY Guitar Riffs...iffs...iffs", using controlled guitar delay to create other voices
• Songs
  • Chris Isaak, "Wicked Games", an example of vibrato effort using a guitar whammy bar. Vibrato is a slowly varying modulation effect.
  • 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".
  • Post Malone, "Circles", demonstrating use of delay, chorusing, and reverb in the vocals, and delay and reverb in the instruments. "Vocal Effects of Post Malone - Circles".
• Performance RNN: Generating Music with Expressive Timing and Dynamics

Last updated 12/08/24. Send comments to bevans@ece.utexas.edu