Biquadratic Filter Applications Using a Fully-Differential Active-Only Integrator

A new class of active filters, real active-only filters is described and possible implementation issues of these filters are discussed. To remedy these issues, a fully-differential active-only integrator block built around current controlled current conveyors is presented. The integration frequency of the proposed circuit is adjustable over a wide frequency range. As an application, a real active-only filter based on the classical two-integrator loop topology is presented and designed. The feasibility of this filter in a 0.35µm CMOS process is verified through SPECTRE simulation program in the CADENCE design tool

Wide Range High Precision CMOS Exponential Circuit Based on Linear Least Squares Approach

A new strategy to implement exponential circuit in CMOS technology is presented in this paper. The proposed method is based on the new approximation function optimized by linear least squares approach to extend the output dynamic range. The current mode method is employed for realization of circuits, because of simple circuitry and intuitive topology. Unlike to the some reported circuits which were designed in the subthreshold region, the proposed design operates in the saturation region which provides acceptable bandwidth for the circuit. In order to validate the circuit performance, the post layout simulation results are presented using HSPICE and Cadence with TSMC level 49 (BSIM3v3) parameters for 0.18 μm CMOS technology. The results demonstrate 78 dB output dynamic range with the linearity error less than ±0.5 dB which shows a remarkable improvement in comparison with previously reported works. A bandwidth of 67 MHz, maximum power consumption of 0.326 mW under supply voltage of 1.5 V, and 0.77% error for temperature variations are further achievement of the design

A probable outbreak of toxoplasmosis among boarding school students in Turkey

ABSTRACTIn total, 171 students from a boarding school in Izmir, Turkey, with mild and non-specific symptoms of toxoplasmosis, were screened during September–October 2002. All 171 students were seropositive for Toxoplasma gondii IgG and IgM. Of 43 students tested, 40 (93%) had low IgG avidity. None showed evidence of ophthalmic involvement. The data suggest that T. gondii may spread rapidly in close living conditions, possibly following exposure to cat litter. This is the largest recent outbreak of toxoplamosis described in the medical literature

Foreign Market Cash Flow Exposure: A Multi-Country, Firm-Level Study

Prompted by recent financial integration and increasingly regional nature of trade and investment flows, we investigate the existence and characteristics of international market-related cash flow exposures for international and domestic companies. Specifically, we study whether firm-level cash flow exposure varies with a regional or global market index in addition to the usual domestic market index. We investigate how this exposure varies with identifiable firm characteristics such international sales exposure and whether this exposure differs systematically across a variety of different countries. We also investigate whether the same model may be used to measure exposure in crisis and non-crisis periods using the Asian economic and financial crisis as a natural experiment. Our empirical investigation relies on a sample of 1325 companies from eight (non-U.S.) countries for the period July 1996 - June 1998. We find significant evidence of regional cash flow exposure across our sample, and this exposure increases in proportion to firm sales in the region. We also find evidence that even domestic companies are influenced by the stock market in other regions. Finally, we find clear evidence of increased exposure for companies with significant sales in Asia during the crisis in that region

An IC random number generator based on chaos

In this work, an integrated random number generator based on oscillator sampling method is presented. The random number generator exploits a continuous-time chaotic circuit as the entropy source. A source-coupled multivibrator is used to transform the generated chaotic signal into jittered oscillations required in the oscillator sampling method. The random number generator circuit is fabricated using 0.35μm CMOS process. The circuit is supplied with ±1.65V and occupies an area of 0.25mm2. The throughput of the RNG is 2Mbit/s and its average power consumption is measured as 35mW at its typical throughput. It is shown that experimental binary data obtained from the fabricated IC pass the four tests of FIPS-140-1 test suite