Data transfer for health monitoring can be highly critical because of life dependency transmitted data. IEEE 802.15.6 is a standard for wireless body area network published in 2012 to satisfy the reliability which is required by health monitoring systems. Ultra wideband is one of proposed physical layer technologies specified in the wireless body area network standard which offers high bandwidth, low power, and low interference with other devices. Orthogonal frequency-division multiplexing is commonly used to transmit the data in many wireless communication standards due to its high spectral efficiency and immunity to the inter symbol interference. In this study, bit-error rate performance for orthogonal frequency-division multiplexing with different interpolation based least square channel estimation is given for wireless body area network channel model. OFDM symbol length and pilot length used in OFDM symbol is investigated in bit error rate -signal to noise ratio graphs.

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Özetçe-Bilimsel ve endüstriyel uygulamalarda çokyüksek veya düşük sıcaklık tespiti için yüksek hassasiyette ölçüm alınmasına ihtiyaç duyulmaktadır. Bu çalışmada sıcaklık ölçümlerinde kullanılan K tipi ısıl çiftlerin sıcaklık ölçüm ve kalibrasyon sistemi tasarımı incelenmiştir. Sistem, ısıl çift tümleşik devresi ve analog sayısal dönüştürücü kullanılarak iki farklı şekilde gerçekleştirilmiştir. Isıl çift soğuk eklem sıcaklık ölçümü için sıcaklık algılayıcıları kullanılmıştır. Kablosuz alıcı-verici eklenerek kablolu ve kablosuz kullanımı geliştirilmiştir. Kontrol, kalibrasyon ve gösterim işlemleri yazılan arayüz programında yapılmaktadır. Program, ısıl çiftin pratik olarak alınabilecek referans sıcaklıklar ile kalibre edilebilecek şekilde yazılmıştır. Oluşturulan sistem ile yapılan örnek ölçümler, kalibrasyon türlerine göre cıvalı termometre ile karşılaştırılmıştır.Analog sayısal dönüştürücü ile gerçekleştirilen sistemin kalibreli sonuçlarının referans alınan termometreye en yakın olduğu bulunmuştur. Anahtar Kelimeler -Isıl çift, Isıl çift kalibrasyonu,Abstract-High sensitive measurement is needed for high and low temperature determination in the scientific and industrial applications. In this study, measurement and calibration system design of K-type thermocouple used in the temperature measurements was examined. The system was performed in two ways using thermocouple integrated circuit and analog-digital converter. Temperature sensors were used for thermocouple cold junction measurement. By adding a wireless transceiver, wired and wireless usages were developed. Control, calibration and display processes were performed with the written interface program. The program was written in a way that practically the thermocouple can be calibrated with reference temperatures. Sample measurements of the established system were compared with the mercury thermometer according to the calibration types. The calibrated results of the performed system with analogdigital converter were found to be the closest to reference thermometer.

Electromagnetic radiation exposure increases with the rise of the wireless communication devices. Electromagnetic radiation, especially near 2400 MHz band, has gradually increased with the widespread of wireless fidelity adapter in indoor environment. In this study, electromagnetic radiation in dwellings where different Wi-Fi adapters and routers are used was assessed by measuring the electric field and compared with other electromagnetic radiation source and the limits set by the Information and Communication Technologies Authority. Measurements were taken in the range of 760-2690 MHz bands used by GSM, 3G/LTE and Wi-Fi technologies. The detected values for all frequencies are significantly lower than the limits of the Information and Communication Technologies Authority. Among the electromagnetic radiation sources, electromagnetic radiation of Wi-Fi adapter is higher than GSM/3G/LTE sources radiation in dwellings. Electromagnetic radiation values in nearest point of high power adapter Wi-Fi antenna are close to the Information and Communication Technologies Authority limit value. Results show that electromagnetic radiation based on Wi-Fi adapters or routers can be higher than GSM based electromagnetic radiation.