Accurate and simple modeling of amplifier dc gain nonlinearity in switched-capacitor circuits

This paper presents an accurate and simple model for dc gain nonlinearity of operational amplifiers used in the switched-capacitor circuits such as the sigma-delta modulators. The proposed model can simply be used in the time-domain system level simulation of sigma-delta modulators to evaluate the effect of amplifier's dc gain nonlinearity on the overall linearity of the modulator as well as in the other switched- capacitor circuits as explored in the paper.Comisión Interministerial de Ciencia y Tecnología TIC2003-0235

Double-Sampling Single-Loop EA Modulator Topologies for Broad-band Applications

This paper presents novel double sampling high-order single loop sigma-delta modulator structures for wide-band applications. To alleviate the quantization noise folding into the inband frequency region, two previously reported techniques are used. The digital-to-analog converter's sampling paths are implemented with the single-capacitor approach and an additional zero is placed at the half of the sampling frequency of the modulator's noise transfer function (NTF). The detrimental effect of this additional zero on both the NTF and signal transfer function is also resolved through the proposed modulator architectures with a low additional circuit requirement

Double-sampled cascaded sigma-delta modulator topologies for low oversampling ratios

This paper presents novel double-sampling cascaded sigma-delta modulator topologies for wideband applications. The proposed modulator structures employ finite impulse response (FIR) noise transfer function (NTF) to achieve the aggressive noise shaping with an additional zero at the half of the sampling frequency to alleviate the quantization noise folding. Cascading of the proposed modulator structures is very simple without any additional circuit requirements.Comisión Interministerial de Ciencia y Tecnología TIC2003-0235

Equalization-Based Digital Background Calibration Technique for Pipelined ADCs

In this paper, we present a digital background calibration technique for pipelined analog-to-digital converters (ADCs). In this scheme, the capacitor mismatch, residue gain error, and amplifier nonlinearity are measured and then corrected in digital domain. It is based on the error estimation with nonprecision calibration signals in foreground mode, and an adaptive linear prediction structure is used to convert the foreground scheme to the background one. The proposed foreground technique utilizes the LMS algorithm to estimate the error coefficients without needing high-accuracy calibration signals. Several simulation results in the context of a 12-b 100-MS/s pipelined ADC are provided to verify the usefulness of the proposed calibration technique. Circuit-level simulation results show that the ADC achieves 28-dB signal-to-noise and distortion ratio and 41-dB spurious-free dynamic range improvement, respectively, compared with the noncalibrated ADC

Edge currents as a probe of the strongly spin-polarized topological noncentrosymmetric superconductors

Recently the influence of antisymmetric spin-orbit coupling has been studied in novel topological superconductors such as half-Heuslers and artificial hetero-structures. We investigate the effect of Rashba and/or Dresselhaus spin-orbit couplings on the band structure and topological properties of a two-dimensional noncentrosymetric superconductor. For this goal, the topological helical edge modes are analyzed for different spin-orbit couplings as well as for several superconducting pairing symmetries. To explore the transport properties, we examine the response of the spin-polarized edge states to an exchange field in a superconductor-ferromagnet heterostructure. The broken chiral symmetry causes the uni-directional currents at opposite edges.Comment: 10 pages, 7 figure

Relationship between Spiritual Experiences and Organizational Commitment with Perceived Stress at the staff of Tehran Oil Hospital

Abstract Introduction: There have been numerous researches carried out in the field of organizational health with the aim of identifying ways to counteract the negative effects of stress. The purpose of this study was to determine the relationship between spiritual experiences and organizational commitment with the perceived stress of the staff of the Tehran Oil Hospital. Methods: The research population of all Tehran Nursing Hospital nursing staff was stratified randomly based on the formula for determining the sample population in 2017. For data collection, standardized questionnaires were used to measure each variable and the extracted data were analyzed using SPSS 22 software. Results: Statistical analysis of the research data showed that there was a significant relationship between spiritual experiences and its components such as meaningful work, sense of correlation and alignment of values, and the pillars of the organizational commitment such as emotional commitment, continuous commitment and normative commitment with perceived stress at a significant level of P<0.05. According to the results of regression with multivariate correlation coefficient for linear combination of variables of spiritual experiences (work with meaning, sense of correlation and values alignment), organizational commitment and perceived stress were equal to MR =35.70and RS =0.19,Which is significant at P<0.0001. Conclusions: The results of this study showed that the spiritual experiences of employees have a positive and significant relationship with organizational commitment and reducing perceived stress. In other words, those with high spirituality feel less stress and more organizational commitment

Evaluation of the Possibility of Instructing Power Plant in Esfahan Province Concerning Environmental, Social and Economic Criteria

In order to study the construction of wind power plants in Esfahan province, the statistics of climatology, the wind speed in four areas of Brojen, Mourche Khart, Varzaneh, Moghar were obtained and then by using a 2.5 MB Tourbine with 928 AV, the potential of wind energy was measured according to environmental, social and economic criteria. The results showed that, the percentage of pollution diffusion in these power plants equals to 0.7 to 5 percent of fossil and gas fuel power plants so that investing on this type of energy can reduce the level of contaminants in the province up to 15 percent. On the other hand, replacing these power plants results in saving 7 million cubic meters water which is equivalent to 2 percent of water consumption. From the economic point of view, in addition to providing the cost of construction during two years, this can be a good potential to make money by reducing fuel consumption and the resulted sale

Low-voltage low-power fast-settling CMOS operational transconductance amplifiers for switchedcapacitor applications

ABSTRACT This paper presents a new fully differential operational transconductance amplifier (OTA) for low-voltage and fastsettling switched-capacitor circuits in digital CMOS technology. The proposed two-stage OTA is a hybrid class A/AB that combines a folded cascode as the first stage with active current mirrors as the second stage. It employs a hybrid cascode compensation scheme, merged Ahuja and improved Ahuja style compensations, for fast settling

Comparing the Resulted Strategies from the SWOT and the SPACE (Electricity Company as Case Study)

Abstract The present study was aimed to compare the implementation of two models in terms of strategic planning. In order to this, firstly, several field studies have been done in terms of the SWOT and the SPACE analysis. In the next step, a team of the meddle and senior managers that have studied in terms of SWOT analysis seek to identify the organization’s strengths, weaknesses, opportunities, and threats and then develop their related strategies. They also develop and indicate the SPACE questionnaire. Based on the results of this questionnaire and determining the organization’s strategic position, they strive to develop the appropriate strategies. Finally, the strategies that have been derived from these models were compared to each other and their strengths and weaknesses were analyzed

Assessment of Female Student’s Satisfaction with the Quality of Food And Environmental Health at Food Services in Tehran University of Medical Sciences, 2013

ensure students are satisfied with the quantity and quality of food as well as hygienic condition in the university’s food services. For this reason, the present study was conducted to investigate female student’s satisfaction with the quality of food and environmental health at food services in Tehran University of Medical Sciences. A number of one hundred of female students, studying at Tehran University of Medical Sciences, were randomly selected. All the selected students were proved to be customers of food services located in one the Medicine, Public Health, Pharmacy, paramedical Sciences, Dentistry, Rehabilitation and Nursing schools. A questioner was prepared as a tool for data collection and its validity and reliability was determined. Afterwards, data analysis was performed using SPSS software (version 23). Results showed that 22% of female students expressed their satisfaction with the quantity of food as “excellent” and 47% as “moderate”. 28% of students rated the food diversity as “moderate” ok”. Seven percent of students reported at least on a case of food poisoning caused by the consumption of food at the university. On average, the overwhelming majority of students expressed their satisfaction as “good” or “medium” with environmental health in at food services in the university, respectively. All the students were aware of the importance of the presence of insects and animals outside the food services and 95%of students reported the presence of insects like beetle, housefly and mosquito and animals like cats, outside the food services. It was concluded that the majority of female students were satisfied with the quantity of food and ranked the quality of food as “medium”. However, they reported some problems regarding hygienic condition inside and outside the dining services and personal health of staff and stated that more attention should be paid by responsible authorities of the university. The student views can be used by these authorities to improve the quality and quantity of food and hygienic condition at food services in Universities