A linear stepping PGA used in CMOS image sensors

A low power linear stepping digital programming gain amplifier （PGA） is designed for CMOS image sensors. The PGA consists of three stages with gain range from one to nine, The gain is divided into four regions and each range has 128 linear steps. Power consumption of the PGA is saved by good tradeoff between variation of amplifier feedback coefficient, pipeline stages and gain regions. With thermometer-binary mixed coding and linear pipeline gain stepping, the load capacitance keeps constant when the gain of one stage is changed. The PGA is designed in the SMIC 0.18 μm process. Simulation results show that the power consumption is 3.2 mW with 10 bit resolution and 10 MSPS sampling rate. The PGA has been embedded in a 0.3 megapixel CMOS image sensors and fabricated successfully.

Income Inequality in Mountain Areas: The Case of Agroforestry Farming Systems in Uluguru Mountains, Tanzania

Land degradation due to use of unsustainable agricultural practices has affected many communities in rural mountain areas rendering them to be more vulnerable to income poverty and inequality. In this case, agroforestry systems promise to offer great solutions as they can be developed in unfavourable conditions where other production systems would either rapidly degrade the land or otherwise would not be possible. However, little is known whether agroforestry can address issues of income inequality in mountain areas. Hence, we conducted a study to investigate the nature and determinants of income inequality in Uluguru Mountains, Tanzania. Specifically, we used the cross-sectional research design and we calculated the income percentile shares, Gini coefficients and the coefficient of variation (CV), to pinpoint the nature of income inequality in the study area. The determinants of income inequality were analysed using the step by step multiple linear model. The results of analysis suggested prevalence of income inequality. Crop production was the main source of income in the agroforestry systems of the study area. Earnings from crops and timber were decreasing income-inequality amongst smallholder farmers. Our disaggregated analysis showed that off-farm income was also decreasing income-inequality for farmers with farmlands located close to homestead, for female-headed households, for farmers who did not access extension services, and those who were members of community-based financial institutions. Estimated incomes increased with household assets, size of farmland, and age of household head. However, the same decreased with household size. We found gender disparity to be one of the key issues that need attention in formulating future policies to reduce inequality. We recommend promotion of livelihood diversification as well as the designing and implementation of tailor-made training and farm financing mechanism to help the less resource-endowed farmers in mountain areas to raise their economic portfolios and social status and combat income poverty and inequality.