Analysis of Vector-Network-Analyzer-Based Power Sensor Calibration Method Application

Radio Frequency (RF) power sensor calibration is one of the essential measurements in RF and microwave metrology. For a reliable and accurate power sensor calibration, there are various methods, such as the substitution method, the direct comparison transfer method (DCTM), and the vector network analyzer (VNA)-based calibration method (VBCM). The VBCM is a method that is derived from the DCTM. It is a preferred method since the VNA has a better measurement capability and has fewer connection requirements for measurement devices. In this study, the milestones and potential application errors of the VBCM are given by considering the connection mistakes, measurement faults, calculation errors, and control software coding problems. At the end of the power sensor calibration measurements with the VBCM, the model function components and the uncertainty calculation examples according to the GUM Bayesian method are also presented in this study. In addition, the advantages and disadvantages of the VBCM compared to the former methods are discussed in this study

Calibration factor comparison between TÜBİTAK UME and SASO NMCC

Bilateral comparison of calibration factor of microwave power sensor was carried out between National Metrology Institute of Turkey (TÜBİTAK UME) and National Measurement and Calibration Center at Saudi Standards, Metrology and Quality Organization of the Kingdom of Saudi Arabia (SASO NMCC). In this comparison, TÜBİTAK UME was pilot laboratory and supplied the travelling standard with N type connector. Nine different frequency points at 0 dBm power level were determined for this comparison in prepared technical protocol. Each participant used their own measurement standards and applied the direct comparison transfer method at comparison. There is a good agreement between TÜBİTAK UME and SASO NMCC results

The Spectrum Of Diseases Causing Fever Of Unknown Origin In Turkey: A Multicenter Study

Objective: The purpose of this trial was to determine the spectrum of diseases with fever of unknown origin (FUO) in Turkey. Methods: A prospective multicenter study of 154 patients with FUO in twelve Turkish tertiarycare hospitals was conducted. Results: The mean age of the patients was 42 +/- 17 years (range 17-75). Fifty-three (34.4%) had infectious diseases (ID), 47 (30.5%) had non-infectious inflammatory diseases (NIID), 22 (14.3%) had malignant diseases (MD), and eight (5.2%) had miscellaneous diseases (Mi). In 24 (15.6%) of the cases, the reason for high fever could not be determined despite intensive efforts. The most common ID etiologies were tuberculosis (13.6%) and cytomegalovirus (CMV) infection (3.2%). Adult Still's disease was the most common NIID (13.6%) and hematological malignancy was the most common MD (7.8%). In patients with NIID, the mean duration of reaching a definite diagnosis (37 +/- 23 days) was significantly longer compared to the patients with ID (25 +/- 12 days) (p = 0.007). In patients with MD, the mean duration of fever (51 +/- 35 days) was longer compared to patients with ID (37 +/- 38 days) (p = 0.052). Conclusions: Although infection remains the most common cause of FUO, with the highest percentage for tuberculosis, non-infectious etiologies seem to have increased when compared with previous studies. (C) 2007 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.WoSScopu