M.Sc.

Abstract: A major source of impairments in Orthogonal Frequency Division Multiplexing (OFDM) wireless communication systems is the imbalance between the real part (Inphase (I)) and the imaginary part (Quadrature (Q)) of the complex signal. This thesis addresses problem theoretically and introduces a blind estimation algorithm to estimate and then compensate the I/Q imbalance. The preformance of a direct-conversion receiver implemented in OFDM systems is analyzed in the presence of I/Q imbalance. Two types of imbalance (mismatch) between the I-and Q-branches are considered here.

Abstract: The digital video coding is a rapidly evolving field. Although its applications are numerous (from TV broadcasting to video conference), bit rate reduction is always needed .This has led to intensive efforts toward effective video compression techniques. In this work an adaptive codec scheme of H.263 standard that depends on transform coding (DCT) and quantization process in compression is proposed. In addition motion estimation search algorithms were used to estimate the predictive frames.

Abstract: This thesis deals with design and analysis of both fullband and subband adaptive filters and compared between them with applications in real speech. . The Normalized Least Mean Square (NLMS) algorithm has been used to make control an adaptive filter. In fullband adaptive filter the system shows slow convergence time compared with subband adaptive filter with lower signal to noise ratio is gave about 0.00003 noise reduction with (S/N) = 3.24 dB according to woman voice and gave 0.000015 with (S/N) =3.68 dB according to man voice when both tested with real speech.