Other Biomedical Signals
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response to each frequency is used to evaluate the performance of the auditory
system in those frequencies. This is simply forming the system function H( f )
using impulses of different frequencies. The bell shape for the response, i.e.,
H( f ), is often considered a healthy shape, and any irregularity in the response
function is measured as the deviation of the curve from a healthy normal bellshape curve.
12.7 SUMMARY
In this chapter, we reviewed a number of biomedical signals that are used in clinical
and research applications. These signals include respiratory signals, cardiovascular
signals such as blood pressure and heart sounds, and MEG. Similarities of these
signals to other signals discussed in more detail in the previous chapters allow us
to process these less widely used signals using the same methods discussed in the
previous chapters.
PROBLEMS
12.1 An airflow signal, g(t), is given in file “p_12_1.mat.” Load this file from the CD
and write MATLAB ® codes to perform the following:
a. Plot the signal in time. Also, plot the magnitude of the DFT of the signal.
b. W hat is the dominant frequency of this signal? What does this frequency
(or equivalently, its corresponding period) represent?
12.2 An airflow signal, g 1 (t); an abdominal excursion signal, g 2 (t); and a thoracic
excursion signal, g 3 (t), are given in file “p_12_2.mat”.* These signals are
captured from the same person during sleep. Load this file from the CD and
write MATLAB codes to perform the following:
a. Pl ot the signals in time and frequency and comment on the dominant
frequencies of the signals.
b. F ind the correlation function among the three signals and comment on the
identified correlations.
REFERENCE
Goldberger, A.L., Amaral, L.A.N., Glass, L., Hausdorff, J.M., Ivanov, P.Ch., Mark, R.G.,
Mietus, J.E., Moody, G.B., Peng, C.K., and Stanley, H.E. (2000, June 13). PhysioBank,
PhysioToolkit, and PhysioNet: Components of a new research resource for complex
physiologic signals. Circulation 101(23):e215–e220.
* From Goldberger et al. (2000).
245
response to each frequency is used to evaluate the performance of the auditory
system in those frequencies. This is simply forming the system function H( f )
using impulses of different frequencies. The bell shape for the response, i.e.,
H( f ), is often considered a healthy shape, and any irregularity in the response
function is measured as the deviation of the curve from a healthy normal bellshape curve.
12.7 SUMMARY
In this chapter, we reviewed a number of biomedical signals that are used in clinical
and research applications. These signals include respiratory signals, cardiovascular
signals such as blood pressure and heart sounds, and MEG. Similarities of these
signals to other signals discussed in more detail in the previous chapters allow us
to process these less widely used signals using the same methods discussed in the
previous chapters.
PROBLEMS
12.1 An airflow signal, g(t), is given in file “p_12_1.mat.” Load this file from the CD
and write MATLAB ® codes to perform the following:
a. Plot the signal in time. Also, plot the magnitude of the DFT of the signal.
b. W hat is the dominant frequency of this signal? What does this frequency
(or equivalently, its corresponding period) represent?
12.2 An airflow signal, g 1 (t); an abdominal excursion signal, g 2 (t); and a thoracic
excursion signal, g 3 (t), are given in file “p_12_2.mat”.* These signals are
captured from the same person during sleep. Load this file from the CD and
write MATLAB codes to perform the following:
a. Pl ot the signals in time and frequency and comment on the dominant
frequencies of the signals.
b. F ind the correlation function among the three signals and comment on the
identified correlations.
REFERENCE
Goldberger, A.L., Amaral, L.A.N., Glass, L., Hausdorff, J.M., Ivanov, P.Ch., Mark, R.G.,
Mietus, J.E., Moody, G.B., Peng, C.K., and Stanley, H.E. (2000, June 13). PhysioBank,
PhysioToolkit, and PhysioNet: Components of a new research resource for complex
physiologic signals. Circulation 101(23):e215–e220.
* From Goldberger et al. (2000).