Мікросистеми, Електроніка та Акустика: науково-технічний журнал, Т. 29, № 2(127)

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https://ela.kpi.ua/handle/123456789/70860

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Перегляд Мікросистеми, Електроніка та Акустика: науково-технічний журнал, Т. 29, № 2(127) за Ключові слова "534.4"

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    A Review of Broadband Microfabricated Ultrasonic Systems for Biomedical Applications
    (КПІ ім. Ігоря Сікорського, 2024) Kostiuk, R. Yu.; Naidas, S. A.
    Starting from an overview of historical aspects of biomedical ultrasound development and its application areas, as well as the brief description of state-of-the art microfabrication technologies, used for capacitive and piezoelectrical micromachined ultrasonic transducers manufacturing, also outlining their modelling approaches, the reader will be further presented with an overview of existing methods for achieving broadband operation both at unit transducer and transducers array levels. Moreover, a generalized signal processing system is discussed, including description of known approaches for building blocks implementation in analog, digital and mixed-signal domains (such as drivers, amplifiers, ADCs, etc.).
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    Estimation of Acting Factor in Stress from Motorbike Sounds
    (КПІ ім. Ігоря Сікорського, 2024) Pareniuk, A. V.; Pareniuk, D. V.
    In the presented study, the search for the acting force in stressor acoustic signal and common everyday acoustic signal is presented. As stressors the signals of acoustic siren of air raid alert and other dangers in the different counties were used, and as everyday signals the sound of motorbikes passing by observers were used. In total five different signals of alert sirens were used. Numerical values presented in research were obtained via frequency analysis with Hann’s window and later – via spectrogram survey. This survey allowed us to find the presence of a steady frequency components in the observed signals, and, most importantly, the presence of rises and falls in said components. These changes in frequency had their speed of change calculated for sirens and motorbikes. For the rise of frequency mean speed in the siren group was calculated as 164 Hz/second, fall was 80 Hz/second. For the motorbike, the speed of frequency rise had a mean value calculated as 166 Hz/second and fall of frequency was estimated as 67 Hz/second. Possible sources for said effect in motorbike signals are Doppler effect and rise of RPM during acceleration. During the statistical analysis via implementation of the non-parametric method due to the character of data distribution in the studied group the lack of statistically meaningful differences between speeds of frequency rise in frequency components of the signals was found. Said rise is presumed to be the acting factor in stress from everyday sounds.