1-4hit |
Yuki OSAKA Fumihiko ITO Daisuke IIDA Tetsuya MANABE
Mode-by-mode impulse responses, or spectral transfer matrix (STM) of birefringent fibers are measured by using linear optical sampling, with assist of polarization multiplexed probe pulse. By using the eigenvalue analysis of the STM, the differential mode delay and PMD vector of polarization-maintaining fiber are analyzed as a function of optical frequency over 1THz. We show that the amplitude averaging of the complex impulse responses is effective for enhancing the signal-to-noise ratio of the measurement, resulting in improving the accuracy and expanding the bandwidth of the measurement.
This paper presents a simple method for comparing the impedance of an artificial mains network (AMN) with the International Special Committee on Radio Interference (CISPR) 16-1-2 standard. The circuit of a vector network analyzer, which is an impedance measurement instrument, is not ideal, and the measured impedances include measurement uncertainties. However, complete uncertainty analysis is not required in the proposed method. By comparing the relative relationship between the measured impedance of an AMN under test and the measured impedance of the original transfer standards whose impedance is modeled by the regulated impedance in the CISPR 16-1-2 standard, conformity to the standard can be determined. The magnitude and phase of the impedance of an AMN can be independently analyzed. To demonstrate the method, we apply it to a commercially available AMN. The comparison result is found to be equivalent to the result based on a complete uncertainty analysis, which confirms that the proposed comparison method is feasible.
Masafumi KATSUMATA Jun-ichi MITSUHASHI Kiyoteru KOBAYASHI Yoji MASHIKO Hiroshi KOYAMA
A test structure has been developed with very low-level current measurement technique and is used to evaluate a very small change of leakage current caused by the trapping and detrapping of electrons or holes. The present technique realizes detection of very low levels of leakage current (minimum detectable current is 510-17 A), which is necessary in the course of evaluating gate oxides. This technique is very useful for the evaluation of retention characteristics and stress induced degradation of gate oxides.
Several research institutions in Europe have developed set-ups for wide-band mobile radio communication measurements. The performance and evaluation has been coordinated in the framework of the cooperation in the field of scientific and technical research within the committees COST 207 COST 231. New parameters have been defined to improve the insight into performance limits of digital radio communication systems which are caused by propagation phenomena. The definitions of these new parameters are presented in the paper. Channel sounders developed in Norway, Denmark, the United Kingdom, Switzerland, France and Germany are described. They are based on considerably different technical principles for evaluation and recording of the measured results. A few results gained in European measurement campaigns are also presented.