This paper proposes a continuous-time filter implementation using integrators based on local-feedback voltage amplifier. Although conventional filter designs use operational amplifier to achieve a large dynamic range, they suffer from bandwidth limitation and large chip area due to frequency compensation capacitors. The proposed integrator mitigates these issues, and it also has capability to scale passive element values which helps to reduce the area occupation or capacitance spread. Simulation results of a leapfrog third-order low-pass filter using the proposed integrator show that HD 3 for 80% input signal of 1.8 V supply voltage is -50 dB.
This paper presents a simple, low voltage CMOS OTA circuit based on two voltage buffer circuits. The simulated results of the proposed circuit with 0.18 /spl mu/m CMOS technology show that it can operate with 1.2V supply voltage, and in less than 0.1% THD for 100kHz, 600mV peak-to-peak differential input signal voltage.
Availability of photovoltaic module fault diagnosis using AC impedance spectroscopy were investigated. Recently, there have been many reports about degradation and failure which occur to polycrystalline silicon photovoltaic modules. Because of these reasons, various diagnosis tools for photovoltaic modules have been invented and introduced; however, the fault mode is hard to determine. Thus, we have been proposing the application of AC impedance spectroscopy, which is widely used to evaluate electrochemical devices, as a diagnosis tool for photovoltaic modules. In this study, we conducted crack test and interconnect ribbon disconnection test to obtain and compare impedance characteristics and I-V characteristics. Equivalent circuit parameters calculated from Nyquist plots as impedance characteristics yielded information to differentiate the fault mode of photovoltaic modules; cracks on photovoltaic modules decrease the parallel resistance and increase the parallel capacitance; interconnect ribbon disconnection increases the series resistance and decreases the parallel resistance. We concluded that AC impedance spectroscopy can detect failures themselves and probably differentiate failure types of photovoltaic modules that cannot be distinguished using I-V characteristics.
'Wind resistant design manual for highway bridges in Japan' has been published in 1991. Before publication of this manual, there were no authorized wind resistant manuals which can be easily applied and cover most kinds of highway bridges. This paper reviews this new manual and reports on the practical application.
