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Wyszukujesz frazę "Schmidt, W." wg kryterium: Wszystkie pola


Wyświetlanie 1-7 z 7
Tytuł:
Acoustic processor of the mine countermeasures sonar
Autorzy:
Rudnicki, M.
Schmidt, J.
Schmidt, A.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/331928.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
This paper presents the concept of an acoustic processor of the mine countermeasure sonar. Developed at the Department of Marine Electronics Systems, Gdansk University of Technology, the acoustic processor is an element of the MG-89, an underwater acoustic station. The focus of the article is on the modules of the processor. They are responsible for sampling analogue signals and implementing the algorithms controlling the measurement cycle and digital signal processing. As it performs the above functions, the device should be highly reliable and resistant to mechanical and weather conditions and ensure a user friendly operation. The functions of the processor software should help with object detection and classification. The results of measurements should be displayed with the shortest possible delay in relation to sounding signals to allow the operator to take decisions quickly and establish if the object poses a risk. The article demonstrates that the acoustic processor designed for and used by the Navy meets these requirements.
Źródło:
Hydroacoustics; 2012, 15; 179-186
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measuring the impedance of ultrasonic transducers
Autorzy:
Lis, W.
Schmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/332169.pdf
Data publikacji:
2004
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
For ultrasonic transducers whose impedance is usually highly variable with frequency, impedance measurement is quite difficult. Cheap and easy devices which are currently available are not suitable for this purpose. Expensive scientific devices are known to be used; usually, they are designed for such measurements in a wide frequency band, from acoustic to microwave range. Simpler and cheaper devices with a narrower band are not commercially available. For hydroacoustic applications, the frequency range may be reduced to 1MHz or even 250 kHz in most cases. This article discusses the possibilities of building a simple and cheap automated system of measuring electric impedance of ultrasonic transducers used in hydroacoustics. The presented results are based on the concept of using a digital oscilloscope as the basic tool for measuring the impedance magnitude and phase. The results have been verified in the original measurement system.
Źródło:
Hydroacoustics; 2004, 7; 143-148
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High accuracy hydroacoustic system to study codend model parameters
Autorzy:
Marszal, J.
Schmidt, J.
Jedel, A.
Schmidt, A.
Wojan, Z.
Zachariasz, K.
Leśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/331608.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
codend model
hydroacoustic system
fishing gear
Opis:
An important task of fishing gear designers is to develop effective selective fishing gears by optimizing its geometry. The high accuracy hydroacoustic system for codend geometry measurements was designed for developing the construction of cod codend for the Baltic fishery. The system consists of 10 pairs of hydrophones, measuring microprocessor device and notebook computer. The high frequency short pulse excitation combined with the matched digital filtering make it possible to obtain high resolution of measure data. Additionally the thermistors mounted in the hydrophones are used to calculate the local sound velocity and enable precision calibration of obtained measuring data. The construction solutions, the measuring procedure and examples of obtained data are presented below.
Źródło:
Hydroacoustics; 2008, 11; 271-278
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High resolution methods of the analysis of acoustic signals in medicine
Autorzy:
Lis, W.
Schmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/332161.pdf
Data publikacji:
1999
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The paper describes an analysis of the possible parametric methods used to estimate the spectrum of short acoustic signals of law oscillations. These kinds of signals often appear in acoustic waves emitted by the temporomandibular joint as it moves [1-2,5]. There is reason to suppose that the frequency which is characteristic of these oscillations could be an essential parameter confirming the pathology of the joint under examination. The measurement of low oscillations is difficult and not accurate, especially when nonparametric methods are used. The paper presents the results of analysis of a simulated short oscillating pulse using the DFT non-parametric method and the parametric method of linear prediction, using Burg algorithm. Finally, results of patient analysis are given, using the FFT and parametric methods.
Źródło:
Hydroacoustics; 1999, 2; 335-340
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic stabilization of beams in sonar with cylindrical array
Autorzy:
Marszal, J.
Leśniak, W.
Salamon, R.
Schmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/332362.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The article presents the principle of operation of the beamformer of sonar with a cylin-drical array. It demonstrates that a modified beamformer can be used for beam electronic stabilization. The paper presents the algorithm of a digital beamformer used to ensure that the beam’s axis is maintained in a horizontal plane when the ship’s pitch and roll are known. Finally, the article gives an overview of the technical problems of electronic beam deflection.
Źródło:
Hydroacoustics; 2006, 9; 119-124
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determining the impedance of ultrasonic transducers by the added elements method
Autorzy:
Lis, W.
Schmidt, J.
Wojan, Z.
Powiązania:
https://bibliotekanauki.pl/articles/332719.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
There are a number of problems involved in measuring complex electrical impedance of ultrasonic transducers. This is because in the frequency function impedance tends to change values rapidly, in particular where resonances are involved. Measuring impedance using accurate bridge methods is a tedious and time-consuming process. While modern automated systems offer shorter test periods and high accuracy, they are very costly. This is why the project aims to implement new methods for computing impedance without these limitations. The article proposes a new, simplified method for measuring the electrical impedance of ultrasonic transducers. In the method complex impedance is calculated from results of two measurements of the transducer’s impedance magnitude only: with the known reactance and without it. To demonstrate the practicality of this method the authors included in the article the value of complex electrical impedance computed using the method and compared these with the results of measurements taken with an automated typical measurement system.
Źródło:
Hydroacoustics; 2005, 8; 99-104
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method for improving multibeam sonar bearing accuracy
Autorzy:
Leśniak, W.
Marszal, J.
Salamon, R.
Zachariasz, K.
Schmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/332790.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
multibeam sonar
sonar bearing accuracy
sonars
Opis:
The paper presents a simple method for improving multibeam sonar bearing accuracy. The principle proposed here is similar to the monopulse method, a solution commonly used in radars and sonars. With no manual or automatic beam rotation, the method offers a substantial reduction in the demand for sonar computational effort. It significantly reduces bearing error for a relatively high signal to noise ratio. The paper gives a boundary value of the output signal to noise ratio which when exceeded satisfactorily improves bearing accuracy.
Źródło:
Hydroacoustics; 2009, 12; 98-108
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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