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6 Applications and Methods in Biosignal Processing

str_ts = ['Time Interval t1s = [0 : ', num2str(L1/F1s), ' s].']

figure(1);

plot(t1s,s1,'b');

title('EMG-Signal');

xlabel('t [s]')

ylabel('s(t) [w.E.]')

% Calculation of power density spectrum in dB with Blackman window

% Pxx: Power density spectrum

% Fxx: Vector of frequency values

[P1xx, F1xx] = pwelch (s1, blackman(512), [], 512, F1s);

figure(3);

plot (F1xx, 10 * log10 (P1xx))

title('Power Density of an EMG Signal');

xlabel('Frequency f / Hz')

ylabel('Power density dB/Hz')

% Linear plot

figure(4);

plot (F1xx, P1xx)

hold on title('Power Density of an EMG Signal');

xlabel('Frequency f / Hz')

ylabel('Power density')

% Calculation of frequency centroid

F1xx_S=sum(P1xx.*F1xx)/sum(P1xx);

str_F1s=['Der Schwerpunkt des Signals S1 liegt bei f1 = ',...

num2str(F1xx_S), ' Hz']

6.2.2 Acoustic-Kinetic Analysis of Osteoarthrosis Patients

Authors of Subsection: Jörg Subke and Benedict Schneider

The analysis of the joint angles and the ground reaction force plays an important role

in the medical assessment of the human movement. If the human movement is limited

by diseases - in our case osteoarthrosis [65] - the medical physician and the physio-

therapist need objective criteria for their clinical diagnosis [34, 37, 64].

Osteoarthrosis is a disease of the joints where the cartilage is damaged. In the

worst case the cartilage is disappeared and the bone to bone contact in the joint will

produce extraordinary pain. In consequence there is the loss of mobility and the pa-

tients cannot perform e.g. their everyday sporting activities like hiking, jogging and