Acoustic Echo and Noise Cancellation System for Hand-Free Telecommunication using Variable Step Size Algorithms

In this paper, acoustic echo cancellation with doubletalk detection system is implemented for a hand-free telecommunication system using Matlab. Here adaptive noise canceller with blind source separation (ANC-BSS) system is proposed to remove both background noise and far-end speaker echo signal in presence of double-talk. During the absence of double-talk, far-end speaker echo signal is cancelled by adaptive echo canceller. Both adaptive noise canceller and adaptive echo canceller are implemented using LMS, NLMS, VSLMS and VSNLMS algorithms. The normalized cross-correlation method is used for double-talk detection. VSNLMS has shown its superiority over all other algorithms both for double-talk and in absence of double-talk. During the absence of double-talk it shows its superiority in terms of increment in ERLE and decrement in misalignment. In presence of double-talk, it shows improvement in SNR of near-end speaker signal

Associated HI absorption in the z=3.4 radio galaxy B2 0902+343 observed with the GMRT

We have made observations of the associated HI absorption of a high redshift radio galaxy 0902+34 at z=3.395 with the Giant Meterwave Radio Telescope in the $323\pm1$ MHz band. We find a narrow absorption line with a flux density of 11.5 mJy at a redshift of 3.397 consistent with that observed by Uson et al. (1991), Briggs et al. (1993) and de Bruyn (1996).A weak broad absorption feature reported by de Bruyn (1996) has not been detected in our observations. We also place an upper limit of 4 mJy (2 $\sigma$) on emission line strength at the position where Uson et al. (1991) claimed to have found a narrow emission line.Comment: To appear in Journal of Astronomy and Astrophysic

On The Violation Of Marshall-Peierls Sign Rule In The Frustrated J1−J2J_{1}-J_{2} Heisenberg Antiferromagnet

We present a number of arguments in favor of the suggestion that the Marshall-Peierls sign rule survives the frustration in the square-lattice Heisenberg antiferromagnet with frustrating next-nearest-neighbor (diagonal) bonds ($J_{1}-J_{2}$ model) for relatively large values of the parameter $J_{2}/J_{1}$. Both the spin-wave analysis and the exact-diagonalization data concerning the weight of Marshall states support the above suggestion.Comment: 8 pages, LaTex, 2 figurs on reques

Bayesian Estimation of Augmented Exponential Strength Reliability Models Under Non-informative Priors

In this article, the augmented strength reliability models are derived by assuming that the Inverse Gaussian stress(Y) is subjected to equipment having exponential strength(X) and are independent to each other.In a real life situations many manufactured new equipments/ products are being failed completely or partially at very early stage of its use, due to lack of its strength. Hence, ASP is proposed to protect such types of failures. The maximum likelihood (ML) and Bayes estimation of augmented strength reliability are considered. In Bayesian paradigm the non-informative types (uniform and Jeffrey’s) priors are chosen under symmetric and asymmetric loss functions for better comprehension. A comparison between the ML and Bayes estimators of augmented strength reliability is carried out on the basis of their mean square errors (mse) by simulating Monte-Carlo samples from posterior distribution by using Metropolis-Hasting approximation