Course detail

Low-frequency and Audio Electronics

FEKT-CNFEAcad. year: 2017/2018

Students become familiar with fundamentals of analog and digital low-frequency and audio signal, then with functionality and design of the pre-amplifiers, correction amplifiers, power amplifiers and filters. The course continues by explanation of sampling, quantization and coding in the area of audio with principles of the audio compression. Emphasis is put on explanation of principles of source coding, error corrections and methods for suppression of the signal degradation with record and playback. Students acquire knowledge of the methods for record and playback in the systems without and with reduction of the bit rate of the audio.

Language of instruction

English

Number of ECTS credits

6

Mode of study

Not applicable.

Learning outcomes of the course unit

The graduate is able to:
- explain principles of analog and digital low-frequency and audio signal transmission
- describe sources and sinks of low-frequency and audio signal
- design appropriate pre-amplifier, correction amplifier, power amplifier of audio filter
- explain principles of sampling, quantization and coding of the sound and audio signals
- explain principles of bit rate compression of the digital sound and audio signals
- characterize system for the record and playback without and with audio compression
- measure parameters of analog and digital audio system or amplifier

Prerequisites

Students registering for the course should be able to explain the basic principles of analog and digital signal processing and function of the basic semiconductor units and amplifiers of the signal. Generally, the knowledge of the Bachelor's degree level is required.

Co-requisites

Not applicable.

Planned learning activities and teaching methods

Teaching methods include lectures and practical laboratories. Course is taking advantage of e-learning (Moodle) system.

Assesment methods and criteria linked to learning outcomes

During the semester, students can obtain up to 30 points for their active work in laboratory. The final exam is awarded by up to 70 points.

Course curriculum

Lectures:
1. Low-frequency and audio signals, transmission and recording, audio processing.
2. Fundamentals of electroacoustics and transducers - microphones and speakers.
3. Low-frequency and audio amplifiers characteristics (class A, AB, B, D and T).
4. Audio preamplifiers, input selectors, loudness perception, volume control.
5. Bass/mid/treble control and audio filters, graphics and parametric equalizers.
6. Power amplifiers, digital class D amplifiers with Pulse Width Modulation control.
7. Digital audio and signal processing, ADC and DAC converters, DSP processing.
8. Digital audio recording without compression (PCM, CD-Audio, SACD, DVD-Audio).
9. Digital audio recording with compression (MiniDisc, MPEG, Dolby Digital, DTS).
10. Fundamentals of audio compression (MP3, ACC, WMA, OGG, ATRAC etc.).
11. Digital audio and multimedia broadcasting DAB/DMB.

Laboratory exercise:
1. Audio preamplifier with the RIAA correction and variable sensistivity.
2. Bass and treble control and Baxandall tone stack.
3. Digital class D and T power amplifier.
4. Active cross-over with separation to subwoofer and 2 way speaker satellites.
5. Fundamentals of digital class D power amplifier with PWM control and modulation.
6. Digital graphics equalizer and limiter with ADC and DSP and PC control.
7. ADC and DAC for audio with adjustable quantization and sampling frequency.
8. Compact Disc Audio DAC and audio measurements using Audio Precision analyzer.

Work placements

Not applicable.

Aims

Lectures are aimed at presenting the methods and technical means for processing, transmission and archive of the sound and audio signals in the area of digital low-frequency technique and audio electronics.

Specification of controlled education, way of implementation and compensation for absences

The content and forms of instruction in the evaluated course are specified by a regulation issued by the lecturer responsible for the course annually.

Recommended optional programme components

Not applicable.

Prerequisites and corequisites

Not applicable.

Basic literature

WIRSUM, S. Abeceda nf techniky. BEN - technická literatura, Praha, 2003. ISBN 978-8086056265. (CS)
KOTISA, Z., VORÁČEK, V. NF zesilovače 1 - 4 díl. BEN - technická literatura, Praha, 2001-2006. ISBN 978-8073000301, 978-8073000530, 978-8073000653, 978-8073002114. (CS)
POHLMAN, K. C. Principles of Digital Audio (Sixth Edition). McGraw-Hill, 2010. ISBN 978-0071663465. (EN)
METZLER, B. Audio Measurement Handbook. Audio Presision, Inc., 1993. Audio Precision document number 0058.0003 r1 (EN)

Recommended reading

TOMAN, K. Reproduktory a reprosoustavy I. Dexon, Karviná, 2001. ISBN 859-1459280805. (CS)
ŠŤÁL, P. Výkonové audio zesilovače pracující ve třídě D. BEN - technická literatura, Praha, 2008. ISBN 978-8073002305. (CS)
TALBOT-SMITH, M. Audio Engineer's Reference Book, Second Edition. Focal press, 1999. ISBN 978-0240516851. (EN)

Classification of course in study plans

  • Programme EEKR-BC Bachelor's

    branch BC-EST , 2. year of study, summer semester, optional specialized

Type of course unit

 

Lecture

39 hours, optionally

Teacher / Lecturer

Syllabus

Introduction to low-frequency and audio electronic and acoustics fundamentals. Low-frequency transmission description. Microphones and speakers. Low-frequency amplifiers classes. Pre-amplifiers, equalizers, dynamic compression and expansion amplifiers. Analog noise reduction. Power amplifiers (discrete, integrated, digital). Selected methods of analog measurements. Analog record of low-frequency signals (CC). Digital processing in low-frequency and audio electronics. A/D and D/A converters, DSP processing. Digital record of low-frequency signals without data reduction (CD-A, DAT). Data reduction and audio compression (MPEG, ATRAC, PASC). Digital record of low-frequency signals with data reduction (AC-3, DTS, DCC, MD) and high definition formats for audio (SACD, DVD-A). Digital audio broadcasting (T-DAB and DRM).

Laboratory exercise

26 hours, compulsory

Teacher / Lecturer

Syllabus

Measurements of the preamplifier characteristics with linear and RIAA corrections.
Measurements of the passive and active corrector characteristics (equalizer) using PC and sound card.
Measurements of the discrete and integrated power amplifiers characteristics.
Measurements of the digital power amplifier (class T) characteristics.
Measurements of the CD recorder characteristics using the analyzer Audio Precision P1DD.
Measurements of the audio characteristics using analyzer Audio Precision ATS-2.
Compression of digital sound and music.