Audio Signal Enhancement

Lecturer: Prof. Dr.-Ing. Peter Jax

Contact: Christiane Antweiler, Sebastian Nagel

Type: Master lecture

Credits: 4

Registration via RWTHonline

Course language: English

The textbook "Digital Speech Transmission" is used as lecture notes. It can be lent in the university library or in the Institute.

Full PDF access from RWTH network (VPN may be required from home office) or login via Shiboleth with your TIM account.

All powerpoint slides of the lecture and the problems of the exercise are available for download at RWTHmoodle.



from Tuesday, April 9, 2024
08:30 - 10:00 AM
IKS, lecture room 4G


from Tuesday, April 16, 2024
10:15 - 11:00 AM
IKS, lecture Room 4G

The lecture "Audio Signal Enhancement" is thematically related to the lecture "Digital Speech Transmission" from the winter term, however, they can be taken independently.

The formal connection to the module catalogs can be found at RWTHonline.


In the lecture "Audio Signal Enhancement" the basic theory of spectral analysis and synthesis systems are introduced. Algorithms for audio signal enhancement are the main topics of this lecture:

  • Filter banks for spectral analysis and synthesis
  • Adaptive Filters
  • Compensation of acoustic echo signals: digital loudspeaking telephone, acoustic human-machine interface
  • Beamforming
  • Single- and multichannel noise reduction: reduction of acoustic noise signals by adaptive filtering, active compensation of acoustic noise, reduction of ambient reverberation
  • Bandwidth extension of speech signals

The aim of this lecture is to teach on the one hand side the fundamental techniques and algorithms of digital speech processing. On the other hand side an overview of the state-of-the-art technology, actual applications and standards is presented. Exercises are offered in the course. Particular topics can be examined at the laboratories "Communications Engineering", "Real-Time Audio Processing", "Matlab Advanced - Digital Signal Processing", and "Audio Processing Using Python" in experiments which are coordinated with this lecture.

The lecture is based on the book: "Digital Speech Transmission", P. Vary, R. Martin, Wiley 2006.


The results of the evaluation of the last years are summarized below. Note: Since the lecture has been renamed in 2018, some evaluations are titled with the previous lecture name Digital Speech Processing II.

Summer Term 2020

Participants of the evaluation(Lecture/Exercise): 7/5

Global grade: 1,1
Concept of the lecture: 1
Instruction and behaviour: 1,1

Global grade: 1
Concept of the exercise: 1
Instruction and behaviour:1