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Treffpunkt MATLAB 2017

TREFFPUNKT MATLAB 2017ITA-TOOLBOX

Johannes Klein, Marco Berzborn,Ramona Bomhardt, Jan-Gerrit RichterInstitut für Technische AkustikRWTH Aachen

Treffpunkt MATLAB 2017

ITA - INSTITUTE OF TECHNICAL ACOUSTICS

Treffpunkt MATLAB 2017

ITA – INSTITUTE OF TECHNICAL ACOUSTICS

Faculty of Electrical Engineering and Communication Technology Two departments: Technical Acoustics (Prof. Michael Vorländer) Medical Acoustics (Prof. Janina Fels)

18 Researchers and 1 senior engineer

Architectural acoustics & virtual reality Electro acoustics & measurement Binaural & spatial audio

Treffpunkt MATLAB 2017

ARCHITECTURAL ACOUSTICS & VIRTUAL REALITY

Room and building acoustics Numerical acoustics Fast simulation methods Auralization

Treffpunkt MATLAB 2017

BINAURAL HEARING & SPATIAL AUDIO

Binaural hearing Array technologies and directivity Medical acoustics and audiology Psychoacoustics

Treffpunkt MATLAB 2017

ELECTRO ACOUSTICS & MEASUREMENT

Pro-audio and loudspeakers development and engineering Vibro-acoustics and TPA Condition monitoring www.ita-toolbox.org

Treffpunkt MATLAB 2017

ita-toolbox.org || git.rwth-aachen.de

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Treffpunkt MATLAB 2017

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Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Quantization: evenly spaced integer values for previouslycontinuous amplitude

Common number of quantization steps:216 ≡± 32767

Quantization errors mostly result in white noise

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Sampling: evenly spaced discretization of previously time-continuous signal

Nyquist theorem: SignalSampling ff 2

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Signal Processing Basics Discrete Fourier Transform (DFT)

Sampling causes mirrored ‘alias’ spectra

discrete representation in frequency domaincauses ‘alias’ impulses in time domain

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Signal Processing Basics Influence of the phase

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Signal Processing Basics Influence of the phase

Treffpunkt MATLAB 2017

DIGITAL SIGNAL PROCESSING

Signal Processing Basics Influence of the phase

Treffpunkt MATLAB 2017

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Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics LTI system

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics Impulse response

Do we have to measure with an impulse?

Pro: directly obtain impulse response Con: not feasible

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics Impulse response

Do we have to measure with an impulse? No!

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics Advantages of extended measurement signals

Distribute more energy over time

Better Signal-to-Noise Ratio (SNR)

Adapt signals to measurement hardware Equalize equipment Optimal dynamic range

More information about the system properties

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics Signal properties

Real-valued time signals – symmetric spectra Periodic time signals – discrete spectra

Frequency resolution depends on measurement time

Averaging to improve SNR

av dB 10lg N

3dB 6dB 9dB 12dB 15dB 18dB2 4 8 16 32 64

Treffpunkt MATLAB 2017

Measurement signals How long to measure?

Tmeas > TReverb

Bin distance

analogous to„sampling“

Measurement period

f

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Tmeas > 1/∆f

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics How does deconvolution work?

Treffpunkt MATLAB 2017

LINEAR TIME-INVARIANT SYSTEMS (LTI)

Signal processing basics How does deconvolution work?

Treffpunkt MATLAB 2017

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