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Lecture notes on signals and systems for undergraduate students.

These teaching materials are based on lectures developed at Department of Electronic Engineering, City University of Hong Kong, Hong Kong SAR, China.

The corresponding MATLAB files can be downloaded at

http://www.ee.cityu.edu.hk/~hcso/MC.rar

The purpose of this note is to provide an effective means to compute the Cramér-Rao lower bound numerically for deterministic parameter estimation problems with the use of symbolic computation in MATLAB.

In this tutorial, we describe how to design a Whole Sky Imager from off-the-shelf components. Subsequently, we use signal processing techniques to derive instantaneous cloud coverage value from the captured images.

We present two contributions in this work: i)Novel electric network frequency (ENF) classification algorithm, and ii)Circuit for measuring power signals from the power grid.We first propose a novel ENF signal estimation algorithm.This algorithm explicitly makes use of the harmonic information present in the signal and estimates the nominal frequency based on the most reliable harmonic. The ENF signal is estimated from the most reliable harmonic by employing a Gaussian weighting window to mitigate the effects of noise. We

The Electric network frequency (ENF) signal is a unique signal for different parts of the world. It is captured by electric devices, and can be used in authentication and automatic synchronization of digital media recordings. In this paper we propose an algorithm to extract ENF from power and audio recordings, and use ENF criterion to identify the region-of-recording. We also propose a design of a circuit to record the electrical power grid.

Power grids are available all over the world for their necessity in all our everyday activities. Each power grid has its own electrical network frequency pattern which is considered as a signature or a finger print of this power grid. Any audio/video recorded in a power grid, whether directly connected to the power mains or not, is affected by the ENF signature of this grid. Post processing could take place to extract the ENF pattern from recordings which can be used in localization of different media signals recorded among grids.