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Timefrequency Spectrograms of Orometer Data
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... of sucking as it changes over time. Irregularity in sucking, visible as ... The sucking in this portion of the signal shows less regularity, so the lower ... – PowerPoint PPT presentation
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Title: Timefrequency Spectrograms of Orometer Data
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Time-frequency Spectrogramsof Orometer Data
- Chris Lang
- Indiana University Southeast
- October 11, 2006
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What this analysis may show
- Frequency of sucking as it changes over time
- Irregularity in sucking, visible as low-frequency
harmonics - Jaggedness of sucks, visible as high-frequency
energy
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Hai 5-4-06 1400 40-60s
- Strong, regular signal with energy concentrated
at about 1.3 Hz (a bit more than one suck per
second)
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Sma 5-10-06 1500 20-40s
- This shows a change of frequency from above 2 Hz
down to 1 Hz
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Mew 5-31-06 1730 (80-100sec)
- This shows a primary frequency of about 1.4 Hz
and a harmonic frequency of about half of that
(0.7 Hz), which occurs because the sucks tend to
alternate in amplitude (tallness)
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Mew 5-31-06 1730 (140-160sec)
- The sucking in this portion of the signal shows
less regularity, so the lower frequency
information (below 1 Hz) is less concentrated.
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DenB 4-17-06 1630 (80-100sec)
- This shows a noticeable amount of energy in
higher frequencies (above 2 Hz), which is due to
the jagged, irregular shape of the suck waveforms.
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More concerning this analysis.
- Performed using a variant of Fourier analysis
known as continuous wavelet transform analysis
which is well-suited for this type of analysis. - For convenience and for more control, the graphs
and spectrograms were generated by software
written by the author but certain commercial
software programs also will draw similar
time-frequency spectrograms. - Acknowledgements Many discussions with Mr. Scott
Buckley have helped me understand what this
analysis might say about infant feeding. I am
also grateful to Scott for providing me with
Phase I and Phase II data.
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