Although most sounds that humans regard as audio begin and end as analog wave phenomena, modern processes for recording, manipulation, storage, transmission and reproduction of these sounds takes place increasingly in the digital domain. This one-day on-site course provides an introduction to the basic principles and processes encompassed in digital audio systems. The focus is on providing course participants with an understanding of digital technology as applied to fundamentally analog phenomena, primarily to enable or enhance human perception, as well the ability to “explain CD’s and MP3 players to your Great Aunt Gertrude.”
The course introduces fundamental concepts followed by a step-by-step explanation of the processes represented in a block diagram of a linear Pulse Code Modulation (PCM) audio recording and playback system. A brief introduction to perceptual coding is presented and specific applications are discussed. Demonstrations using PC-based real-time analysis software and recordings of digital audio artifacts and psychoacoustic phenomena are included.
This course is intended as an introduction or review for EE’s, ME’s, CS/CSE grads and others who find themselves working on audio-related products or systems with the benefit of a course or two in DSP or vibrations, but without formal study of audio engineering or digital audio. The course is also suitable as an introductory overview for those who market, sell, distribute or install consumer, commercial¸ car audio or professional audio products and systems, as well as those whose work involves recording, storage, transmission or reproduction of audio signals using anything other than an analog tape recorder.
- Properties of audio signals; real time analysis
- Fundamental Processes
- binary codes; discrete time sampling, aliasing; Quantization, quantization error, S/E vs. SNR; dither; examples of errors and artifacts
- Digital Recording
- modulation coding; Linear PCM; anti-aliasing filters; sample & hold, jitter; analog-to-digital conversion, successive approximation; multiplexing, error correction, interleaving; channel codes
- Digital Reproduction
- Linear PCM; digital-to-analog conversion; output sample & hold; output filters; oversampling; noise shaping; Compact Disc Digital Audio
- Psychoacoustics and Perceptual Coding
- Hearing thresholds, loudness contours; critical bands and masking; examples
- data reduction coding; MP3 and AAC; proprietary formats; surround and HD formats
Dr. Chris Barber is the founder of Multipath Science and Engineering Solutions and has over twenty years’ experience in applied acoustic research ranging from acoustic testing of naval ships to characterization of professional audio systems. He has taught courses and advised students in acoustics, audio and electrical engineering at the undergraduate, graduate and professional continuing education levels.
Course participants receive a hard copy of the instructor’s course notes and selected reference materials. Following the course, opportunities are provided to schedule a web-based follow-up Q&A session between the instructor and course participants.