Volume 3, Issue 4, April 2013

Suppression of Noise in Speech using Adaptive Gain Equalizer [Download Paper]

Anil Chokkarapu, Sarath C Uppalapati and Abhiram Chinthakuntla

Abstract— The quality of speech during the communication is generally effected by the surrounding noise and interference. To improve the quality of speech signal and to reduce the noise, speech enhancement is one of the most used branches of signal processing. For the reduction of noise from speech signals, one method is the AGE (Adaptive Gain Equalizer). This report presents a real time implementation of an AGE noise suppressor method using Uniform FFT (Fast Fourier Transform) modulated filter bank for speech communication system. Our result shows that this method offers low complexity, low delay and high flexibility makes this method suitable for wide range of implementations. 

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Low cost Ultra Wide Band hybrid radar design using virtual reference tags as road safety feature in vehicles [Download Paper]

Hadi Abdullah, Ijaz Khan and MohdShamian Bin Zainal

Abstract—This paper presents a hybrid radar technique of received signal strength (RSS) and time of arrival (TOA) as an application in vehicles. Both techniques are used to locate intruding vehicles within a specific area. Received signal strength and time of arrival technique require high level transmitter and receiver synchronization. To overcome this drawback virtual reference tags (VRTs) are used. These VRTs are spread symmetrically over the covered area of radar design. Being virtual their information is only stored in receivers. The radar design is multistatic radar consisting of one transmitter and three receivers. Transmitter is placed in back, two receivers on sides and one receiver in front of vehicle. Ultra wide band (UWB) signal pulses are used, giving radar system accuracy even when vehicle is at high speeds. Also in this paper three different cases of intruders are discussed considering a static radar system for intruder detection. After calculating accuracy and number of VRTs, mobile radar system is designed for vehicles and two different scenarios are discussed. 

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Pulse Broadening Induced by Second Order and Third Order Dispersion in a Dispersive Fiber [Download Paper]

Sher Shermin A. Khan and Md. S. Islam

Abstract— As data rates of telecom systems increase, new technical challenges appear, including the adverse effects of signal broadening caused by second and third order dispersion. The frequency dependence of the propagation velocity leads to pulse broadening simply because different spectral components of the pulse disperse during propagation and do not arrive simultaneously at the fiber output; the shorter part of an optical pulse propagates faster than its larger part, resulting in progressive pulse broadening. To estimate the extent of pulse broadening in single mode fiber, an analytic expression for the pulse broadening is obtained. It is found that the pulse broadening induced by dispersion fluctuation can be quite large at high bit rates, and the effect of third order dispersion is also significant at high bit rate.