Audio Signal Enhancement

Lecturer: Prof. Dr.-Ing. Peter Jax

Contact:Christiane Antweiler, Sebastian Nagel

Type: Master lecture

Credits: 4

Lecture in RWTHonline
Exercise in RWTHonline
Learning room RWTHmoodle
(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.

All powerpoint slides of the lecture and the problems of the exercise will be sold during the first lecture as well as by Irina Ronkartz.

These scripts are also available for download at the RWTHmoodle.



from Tuesday, April 13, 2020
08:30 - 10:00


from Tuesday, April 13, 2021
10:15 - 11:00


The exam is held orally on 24.02., 09.03. and 23.03. Dates are given by arrangement. Please contact Ms Sedgwick ,

Please note: The exam takes place via Zoom in digital form. Please have your student ID (BlueCard) ready.

The lecture "Audio Signal Enhancement" goes back to the former lecture "Digital Speech Processing II" (summer term 2017). It is thematically related to the lecture "Digital Speech Transmission" (previously: "Digital Speech Processing I") from the winter term, however, they can be taken independently.

The lecture "Audio Signal Enhancement" is amonst others part of the master studies compulsory elective modules

  • Information and Communication Technology: IK.A
  • Computer Engineering: TI.A
  • Biomedical Engineering: BMT.B

or can be chosen as elective modules.


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", and "Matlab Advanced - Digital Signal Processing" 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