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Lecture "Adaptive Filters"


Basic Information
Lecturers: Gerhard Schmidt (lecture) and Tobias Hübschen (exercise)
Room: Zoom
Language: English
Target group: Students in electrical engineering and computer engineering
Prerequisites: Basics in system theory

Students attending this lecture should learn the basics of adaptive filters. To achieve this, necessary algorithms will be derived and applied to problems arising in speech and audio processing. The algorithms comprise Wiener filtering, linear prediction, and adaptive schemes such as the NLMS algorithm, affine projection, and the RLS algorithm. For applications from speech and audio processing we use noise and reverberation reduction, echo cancellation, and beamforming.

Topic overview:

  • Introduction and application examples
  • Signal properties and cost functions
  • Wiener filter and principle of orthogonality
  • Linear prediction
  • RLS algorithm
  • LMS algorithm and its normalized version
  • Affine projection algorithm
  • Control of adaptive filters
  • Efficient processing structures
  • Applications of linear prediction



Summer term 2021: The lecture will be conducted using Zoom. The exercise will consist of both on-demand videos and of two Zoom meetings where student questions can be discussed. To receive all relevant information during the semester, including links to the Zoom meetings, please register for this lecture in Olat.

04.04.2021 - For the zoom link please have a look at the corresponding OLAT page. We will start the lecture on 20.04.2021 at 08:15 h.

23.03.2021 - Preliminary lecture and exercise schedule is available.



The following schedule regarding lectures and excercises is preliminary and may be adapted during the semester.

Date Lecture Exercise
20.04.2021 Introduction -
27.04.2021 Wiener filter Wiener filter (video)
04.05.2021 Linear prediction Linear prediction (video)
11.05.2021 Algorithms part 1 -
18.05.2021 Algorithms part 2 Algorithms (video)
25.05.2021 - Wiener, LP, Algorithms question time (zoom, will also occupy some of the lecture time)
01.06.2021 Control Control (video)
08.06.2021 Processing structures Processing structures (video)
15.06.2021 Applications of linear prediction -
22.06.2021 - Control, Structures, Applications question time (zoom, will also occupy some of the lecture time)
29.06.2021 Student talks Student talks
06.07.2021 Student talks Student talks


Lecture Slides

Link Content
Slides of the lecture "Introduction"
(Introduction, boundary conditions of the lecture, applications)
Slides of the lecture "Wiener Filter"
(basics, principle of orthogonality, suppression of background noise)
Slides of the lecture "Linear Prediction"
(derivation of linear prediction, Levinson-Durbin recursion)
Slides of the lecture "Algorithms (Part 1 of 2)"
(RLS algorithm, LMS algorithm [part 1 of 2])
Slides of the lecture "Algorithms (Part 2 of 2)"
(LMS algorithm [part 2 of 2], affine projection algorithm)
Slides of the lecture "Control"
(basic aspect, pseudo-optimal control parameters)
Slides of the lecture "Processing Structures"
(polyphase filterbanks, prototype lowpass filter design)
Slides of the lecture "Applications of Linear Prediction"
(Improving the speed of convergence, filter design)



Link Content
Extension for the lecture "Wiener Filter"
(derivation of the error surface)


Matlab Demos

Link Content
Matlab demo (GUI based) for adaptive system identification
Matlab demo (GUI based) for adaptive noise suppression
Matlab demo (GUI based) for linear prediction
Matlab demo (GUI based) for the NLMS algorithms
Matlab demo (GUI based) for prediction-based filter design



The exercise will consist of two parts using different media. For most lecture topics an individual exercise video will be uploaded. These videos can be watched on demand. Some additional course material will be provided alongside these videos.

The on-demand videos will be supported with two live zoom sessions. Here, students will be able to ask topic-related questions. Students are also encouraged to submit their questions ahead of time so the answers can be supported with slides or other material.

Videos will go live and zoom sessions will be conducted according to the (preliminary) schedule above.

Video Content Material

Wiener filter:

  • summary
  • comprehension questions
  • python demo

Linear prediction:

  • summary
  • comprehension questions
  • signal visualization
  • python demo


  • summary
  • explaining algorithms
  • comprehension questions
  • python demo


  • motivation/summary
  • comprehension questions
  • python demo

Processing structures:

  • summary
  • comprehension questions
  • python demo


Student Talks

At the end of the semester, each student will give a talk about a certain topic as a prerequisite to sit the exam. The aim is both to give you the chance to work on an adaptive filter-related topic that interests you, and to improve your presentational skills. The talks should take ten minutes, plus 2.5 minutes of discussion and 2.5 minutes of feedback.

Please contact This email address is being protected from spambots. You need JavaScript enabled to view it. with your topic suggestion. Below you can find the current schedule of the talks.


Date Room Time Topic Presenter(s)
29.06.2021 Zoom 08:20 h ECG Signal Enhancement Using Adaptive Filters Moritz Boueke
29.06.2021 Zoom 08:35 h Active Noise Cancellation for Headphones Karolin Krüger, Christian Kanarski
29.06.2021 Zoom 09:00 h Feedback Suppression Finn Röhrdanz
29.06.2021 Zoom 09:15 h Adaptive Filters in Power Electronics Dario Metschies
29.06.2021 Zoom 09:30 h Adaptive Beamforming in Radar Systems Klara Görnig
29.06.2021 Zoom 09:45 h Break  
29.06.2021 Zoom 09:55 h Adaptive Filters in Medical Image Processing Mohammadmahdi Asrar, Karoline Gussow
29.06.2021 Zoom 10:20 h Noise Suppression Şevval Buse Tokmak
29.06.2021 Zoom 10:35 h Adaptive Multi-Rate Codecs Patricia Fuchs
29.06.2021 Zoom 10:50 h Adaptive Filters in Fast HRTF Measurement Simon Hesselbrock
29.06.2021 Zoom 11:05 h Adaptive Filters for GPS Jan-Niklas Busse
29.06.2021 Zoom 11:20 h Adaptive Filters in Camera Image Restoration Golam Sarowar Jahan Rifat
06.07.2021 Zoom 08:20 h Localization and Tracking Jonas Olschewski
06.07.2021 Zoom 08:35 h Adaptive Filter for In-car Communication Systems Dennis Zdetski, Leon Neidhardt
06.07.2021 Zoom 09:00 h Hearing Aids Wajid Ali
06.07.2021 Zoom 09:15 h Adaptive Filters in Biomedical Applications Usama Adeel, Rashid Obaid
06.07.2021 Zoom 09:40 h Break  
06.07.2021 Zoom 09:50 h Adaptive Filters in Finance Fabian Kuhnert
06.07.2021 Zoom 10:05 h Adaptive Filters for Robotic Systems Tim Schmidt



If you do not have a date for the exam yet please register in the online booking system (once the exam dates have been set). You can find the booking system here.


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