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    A new simple method for analysing of thermal noise in switched-capacitor filters

    , Article International Journal of Electronics ; Volume 99, Issue 12 , Feb , 2012 , Pages 1729-1737 ; 00207217 (ISSN) Rashtian, M ; Hemmatyar, A. M. A ; Hashemipour, O ; Sharif University of Technology
    2012
    Abstract
    Thermal noise is one of the most important challenges in analogue integrated circuits design. This problem is more crucial in switched-capacitor (SC) filters due to the aliasing effect of wide-band thermal noise. In this article, a new simple method is proposed for estimating the power spectrum density of output thermal noise in SC filters, which have acceptable accuracy and short running time. In the proposed method, first using HSPICE simulator, accurate value of accumulated sampled noise on sampler capacitors in each clock state is achieved. Next, using difference equations of the SC filter, frequency response of the SC filter is shaped by time domain analysis. Based on the proposed... 

    AFM spectral analysis of self-agglomerated metallic nanoparticles on silica thin films

    , Article Current Nanoscience ; Volume 6, Issue 1 , 2010 , Pages 116-123 ; 15734137 (ISSN) Akhavan, O ; Sharif University of Technology
    2010
    Abstract
    Stochastic parameters of self-agglomerated metallic nanoparticles on a dielectric film surface were studied using atomic force microscopy (AFM) analysis. In this regard, the rough surfaces including the nanoparticles were analyzed and characterized using structure function, roughness exponent and power spectrum density of the AFM profiles and their gradients, for different metal concentrations and heat treatment temperatures. The diffusion parameters, such as activation energy, of the nanoparticles initially accumulated on the surface into a porous and aqueous silica thin film were obtained using the AFM spectral analysis of the profiles and their gradients. It was found that the tip... 

    AFM stochastic analysis of surface twisted nanograin chains of iron oxide: a kinetic study

    , Article Journal of Physics D: Applied Physics ; Volume 42, Issue 6 , 2009 ; 00223727 (ISSN) Akhavan, O ; Azimirad, R ; Sharif University of Technology
    2009
    Abstract
    We have studied the stochastic parameters of surface iron oxide nanograin chains, 97 nm in diameter and 2.4 νm in length, prepared at different annealing temperatures, using atomic force microscopy (AFM) spectral analysis. In this regard, the roughness of the thin films including self-assembled twisted nanograin chains has been analysed and characterized using the height-height correlation function, the roughness exponent as well as the power spectrum density of the AFM profiles and their gradient, for the different annealing temperatures. The tip convolution effect on the stochastic parameters under study has also been investigated. The kinetics of the formation of nanograins on the film...