Filtreler

2002 - 20092
Filtreleri Sıfırla

Ayarlar

Yazar: Tekeş, Coşkun × Erişim Hakkı: Attribution-NonCommercial-NoDerivs 3.0 United States ×

Arama Sonuçları

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Yayın
    Co-array optimization of CMUT arrays for forward-looking IVUS
    (IEEE, 2009-09) Tekeş, Coşkun; Karaman, Mustafa; Değertekin, Fahrettin Levent
    The ring annular array structure is a preferred configuration for implementing Forward-Looking IVUS (FLIVUS) catheters as it allows for volumetric imaging as well as use of a guidewire at the center. CMUT technology is promising for these arrays especially with the flexibility of locating array elements on the circular donut area efficiently. To take advantage of this flexibility, in this study, we introduce a new co-array sampling strategy that improves imaging performance while keeping the number of firings at a level suitable for real-time imaging. The presented co-array sampling strategy is based on the idea of adjusting the element density of the co-array rings in radial direction to suppress side lobes. In non-uniform sampling of the co-array with a given number of firings, the inter-element distances are adjusted both in radial and angular direction from inner ring to outer ring to fit a given apodization function. To test the imaging performance, we performed numerical simulations of the co-array with non-uniform sampling fitting to the raised-cosine apodization. The simulation results shows that sidelobe level can be reduced more than 10 dB by using non-uniform co-array sampling. This approach does use uniform weighting of all Tx and Rx elements in beamforming, and hence does not cause any SNR loss for apodization.
  • Küçük Resim
    Yayın
    Implementation of a fixed cellular terminal with mobile phone
    (Işık Üniversitesi, 2002-09) Tekeş, Coşkun; Yarman, Bekir Sıddık Binboğa; Işık Üniversitesi, Fen Bilimleri Enstitüsü, Elektronik Mühendisliği Yüksek Lisans Programı
    The thesis reports the design and realization of a fixed cellular terminal (FCT) device which works with a mobile phone as a GSM Module. The design is emphasized at the structure not to be complex and suitable to be used in mass production. Before starting our design, our currently available FCT products and their functional properties are studied and the most important and usefull properties are fixed. This design is not only a theorical project, it is also realized as a mass product and take part in the market as a product.