Module Directory detail

EE304-6-SP: AUDIO ENGINEERING

Year: 2009/10

Department: Computer Science and Electronic Engineering (School of)

Essex credit: 15
ECTS credit: 7.5
Study Abroad credit:
Full Year students: 4 credits. Spring and Summer Terms students: 4 credits .

Pre-requisites: EE204

Staff

Supervisor:	Professor M Hawksford
Teaching Staff:	Professor M Hawksford
Contact details:	General Office, email: ces-genoffice (non-Essex users should add @essex.ac.uk to create full e-mail address), Telephone 01206 872770

Study Abroad: Available to Study Abroad Students

Module is taught during the following terms
Autumn		Spring		Summer

Module Description

Learning Outcomes

The course aims to introduce a range of audio systems and to engender an understanding of how the design of an electronic system can be influenced by the device and circuit technology on the one hand, and by user requirements on the other. The course emphasises circuit principles and design techniques and presents a number of audio specific topics embracing both low-noise, small-signal amplifiers and high-level power amplifier systems, the latter including both high efficiency output stage design and error-correction procedures. To complement these topics, aspects of loudspeaker theory, measurement techniques and digital processing are also presented that relate to
modern, high-performance audio systems. A case study of a loudspeaker system employing digital signal processing is described to link together the work on analogue and digital systems. The course is illustrated with a number of practical demonstrations of audio technology.

1. Comprehend the basic characteristics and psychoacoustic requirements of an audio system
2. Design small signal audio amplifiers and power amplifiers
3. Use servo amplifiers in low- and high-level audio amplifiers
4. Comprehend the circuit principles of a graphic and parametric equalizer
5. Linearise audio amplifier circuits using error correction and feedback
6. Understand measurement techniques to assess linear and non-linear system performance
7. Understand the operation and modelling of moving-coil loudspeaker systems
8. Comprehend the fundamentals of digital audio systems for high-quality applications.

Outline Syllabus

Introduction to Audio Systems, Objective and Subjective Parameters:
Introduction to the audio industry and the professional role of the Audio Engineering Society. Hearing sensitivity and subjective response, Fletcher Munson characteristics, minimum audible field (MAF), masking thresholds. Efficiency and sensitivity in loudspeaker systems, typical signal levels encountered in audio electronics.

Linear and Non-linear System Theory, Transfer Function and Distortion Measurement Techniques:
Relationship of system impulse and transfer function via Fourier transform. System measurement using periodic impulse response excitation (PIR) and maximum-length sequence (MLS), time aliasing distortion. Loudspeaker frequency response measurement in a finite, non-anechoic space. Frequency domain verses time domain resolution, windowing, aperture distortion, noise averaging. Representation of a memory-less non-linear system using Taylor power series representation of transfer characteristic, total harmonic distortion (THD) and inter-modulation distortion (IMD) measurements, distortion factor (DF) measurements.

Amplifier Design for Low-level Signals:
Definition of line-level amplifier, single-ended and differential configurations. Bipolar transistor as a non-linear transconductance device, non-linear modelling. Effects of feedback on input, output impedance and non-linearity. Error-correction circuit techniques. Complementary and differential amplifier design with and without overall feedback.

Noise in Amplifiers:
Noise factor, equivalent noise models, cascaded and parallel stages. Effect of feedback on noise figure. Optimal noise design. Noise analysis of common circuit examples.

Frequency Response Shaping:
Equalization stages, frequency contouring (tone controls), parametric and graphic equalizers.

Servo Amplifiers:
Servo amplifier as an active, low-frequency feedback device, non-inverting and inverting integrator topologies, servo amplifier classification, factors effecting dc output offset voltage, dc-coupled amplifier circuit example.

Power Amplifiers:
Output stage classification, single ended class A, complementary class A, class AB, class B. 2 and 3 transistor compound output stages. Safe operating regions, power limitations, secondary breakdown. Power bandwidth and slew-rate limiting. Crossover distortion, biasing techniques, amplified diode with thermal compensation. Feedforward error correction, Quad current-dumping amplifier. Bridge output stages. Input stage and intermediate stage design. High-efficiency output stage topologies. Examples of commercial circuit designs.

Loudspeaker Systems:
Electro-acoustic transduction using pistonic radiator, moving coil drive unit and equivalent circuit representation. Multi-way loudspeaker systems and mathematical description of the all-pass family of crossover networks up to the fourth-order Linkwitz-Riley alignment (L-R 4). Digital-and-active loudspeaker system.

Digital Audio:
Review of DVD-audio and SACD high-resolution audio formats. Sampling theory, quantization, dither, oversampling and decimation. Noise shaping and sigma-delta modulation.

Learning & Teaching Methods

Lectures and Classes

Assessment
40 per cent Coursework Mark, 60 per cent Exam Mark

Exam Duration and Period

2:00 hour exam during Summer Examination period.

Other information -
STUDENTS SHOULD NOTE THAT THIS MODULE INFORMATION IS SUBJECT TO REVIEW AND CHANGE

Bibliography
HORROWITZ and HILL, The Art of Electronics, Cambridge University Press (2nd edn)
WATKINSON, J., An Introduction to Digital Audio, Focal Press
COLLOMS, M., High Performance Loudspeakers, Wiley
STEIGLITZ, K., A Digital Signal Processing Primer, Benjamin Cummings
DUNCAN, B., High Performance Audio Amplifiers, Newnes

Further information

online course materials for EE304-6-SP
School of Computer Science and Electronic Systems online course materials in the Course Materials Repository
School of Computer Science and Electronic Systems website

Should you have any queries about the Module Directory pages, please contact Lynne Brown, Systems Administration Office, Academic Section; email: lynneb. Non-essex users should add @essex.ac.uk to create the full email address.