Digital Speech Processing

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Lecturer: Prof. Dr.-Ing. Peter Jax

Contact: Christiane Antweiler, Maximilian Kentgens

Type: Master lecture
The lectures can also be attended in reverse order.

Credits: 4

Digial Speech Transmission I
(Winter term 2016/17):

Campus Lecture
Campus Exercise
Learning room L2P 
(Registration via campusOffice)

Course language: German (slides in 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 L²P learning room.


Digital Speech Processing I


from Thursday, October 12, 2017
08:30 - 10:00
Lecture room 4G


from Thursday, October 12, 2017
10:15 - 11:00
Lecture room 4G

Digital Speech Processing I & II

Consultation hours:

Thursday, March 15, 2018
10:00 - 12:00

Tuesday, March 30, 2018
10:00 - 12:00

Lecture room 4G

Exam: Digital Speech Processing I & II

Thursday, March 22, 2018
14:30 - 16:00
Lecture room Roter Hörsaal AM

Process time: 1.5 hours
The exam in part I takes 1.5 hours.

Remark: In the winter term 2017/2018 the exam in part II is held orally. Dates are given by arrangement. Please contact Simone Sedgwick to arrange dates for exams.

Resources: Written resources (e.g., lecture notes or books) are not permitted. The use of pocket calculators is allowed.

Note: Please bring along your student ID (BlueCard)!


Monday, April 9, 2018
11:00 - 12:00
Lecture room 4G

The lectures "Digital Speech Processing I and II" have been replaced in the summer term 2018 by the lectures "Digital Speech Transmission" and "Audio Signal Enhancement".


In this two term lecture the fundamental issues, standards, and recent trends in speech communication technology are presented. The first part (DSV I) deals with the fundamentals of speech production, hearing, psycho-acoustic aspects and speech coding.

Digital Speech Processing I – Digital Speech Transmission:

  • Spectral transformations
  • Stochastic signals and estimation
  • Linear prediction
  • Quantization
  • Speech coding: model-based predictive coding, vocoder, adaptive quantization, adaptive prediction in the time domain, adaptive coding in the frequency domain, subjective speech quality, standards, realization aspects.

In the second part (DSV II) digital filter banks are introduced. Algorithms for audio signal enhancement are the main topics of this lecture.

Digital Speech Processing II – Audio Signal Enhancement:

  • Filter banks for spectral analysis and synthesis
  • Error concealment and soft decision source decoding, reduction of annoying effects due to residual bit errors
  • Bandwidth extension of speech signals
  • Single- and multichannel noise reduction: reduction of acoustic noise signals by adaptive filtering, active compensation of acoustic noise, reduction of ambient reverberation
  • Compensation of acoustic echo signals: digital loudspeaking telephone, acoustic human-machine interface

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 for both parts of 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 relies on the book: "Digital Speech Transmission", P. Vary, R. Martin, Wiley 2006.


The results of the evaluation of the last years are summarized below.

Digital Speech Processing I

Winter term 2017/2018

Participants of the evaluation: 17
Global grade: 1,3
Conzept of the lecture: 1,3
Instruction and behaviour: 1,3

Participants of the evaluation: 14
Globalindikator: 1,4
Conzept of the exercise: 1,5
Instruction and behaviour: 1,3


Digital Speech Processing II

Summer term 2017

Participants of the evaluation(Lecture/Exercise): 8/9

Global grade: 1,3
Conzept of the lecture: 1,3
Instruction and Behaviour: 1,2

Global grade: 1,3
Conzept of the exercise: 1,3
Instruction and Behaviour: 1,4