O. Sangaroon

Secret key reconciliation using BCH code in quantum key distribution

Due to imperfection in quantum key distribution (QKD) an uncorrected secret key transmitted via quantum channel exists at the receiver side. This paper presents an alternative method to recover those quantum key by using BCH codes - a class of error control coding (ECC). Application of BCH codes to source coding with side information is described for quantum key reconciliation. Unlikely to many previous protocols, the proposed scheme aims to reduce public communication with acceptable quantum bit error rate and a number of disclosed bits; therefore, it is suitable to applications of high speed QKD.

Bandwidth Enhancement of CPW-Fed Slot Antenna with Inset Tuning Stub

The coplanar waveguide fed slot antenna with inset tuning stub is proposed for WLAN and WiMAX applications. This antenna consists of a rectangular patch element embedded with a tuning stub fed by CPW feed line. The antenna is designed for match impedance with 50 ohm of characteristic impedance of transmission line by using inset tuning stub for wideband matching. The simulation and measurement results show good agreement operation, which range of bandwidth can be achieved from 1.65 GHz - 6.35 GHz or 117%, suitable for applications to cover 2.4/5.2/5.8 GHz of WLAN bands and 2.5/3.5/5.5 GHz of WiMAX bands. The characteristics of antenna are proposed and analyzed for return loss, bandwidth, current distribution, voltage standing wave ratio and far field radiation patterns.

Double rectangular slot loop antenna for dual frequency

This paper presents the technique for reducing size of double rectangular slot loop antenna fed by microstrip line for dual frequency. The two difference configurations of double rectangular slot loop antenna are proposed for comparison on bandwidth and size of antenna. These antennas are designed for dual frequency support WLAN system coverage IEEE 802.11b/g (2.4-2.4835 GHz), IEEE 802.11j (4.90-5.091), IEEE 802.11a (5.15-5.35 GHz), and IEEE 802.16d (5.7-5.9 GHz). The PCB-FR4 substrate with dielectric constant (epsivr) 4.5 of thickness 1.6 mm is chose for low cost. The simulation results of these slot antennas are analyzed by using method of moment (MoM) from IE3D software. In this case, the result of bandwidth for low frequency and high frequency of one antenna are 11.29% and 62%, and other are 6.1% and 75.5%, respectively. The size with ground plane of double slot loop antenna can be reduced 12.9% or can be reduced size of double slot loop antenna about 21.5% when set the new inner conductor.

CPW-fed slot antenna with inset L-strip tuning stub for ultra-wideband

The coplanar waveguide fed slot antenna with inset L-stripe tuning stub is proposed for UWB applications. The antenna consists of two rectangular slots separated by center strip with CPW feed line. This antenna is design for match impedance with 50 ohm of characteristic impedance of transmission line by using inset L-stripe tuning stub for wideband matching. By adjusting dimension of inset L-strip tuning stub, the range of bandwidth can be achieved 144.6% (1.80 GHz - 11.2 GHz) of the center band coverage standard of IEEE 802.15a for ultra wideband operation. The characteristics of antenna are proposed and analyzed for instance input impedance, return loss, bandwidth, VSWR, and far field radiation patterns.

Inset dual U-strip slot antenna fed by microstrip line for WLAN applications

This paper presents the slot antenna fed by microstrip line with inset U-strip for dual frequency operates in WLAN applications. The rectangular slot antenna is proposed for comparison between with and without U-strip in slot antenna by using three configurations of slot antenna. This antenna is designed for dual frequency used in WLAN system coverage IEEE 802.11 b/g (2.4-2.4835 GHz), IEEE 802.11j (4.90-5.091), IEEE 802.11a (5.15-5.35 GHz) and WiMAX of IEEE802.16d (5.7-5.9 GHz). The PCB-FR4 substrate with dielectric constant (epsivr) 4.5 of thickness 1.6 mm is chose for low cost. The simulation results of these slot antennas are analyzed by using Method of Moment (MoM) from IE3D Software. Finally, the result of bandwidth at low frequency and high frequency of the desirable antenna are 9.76% and 31.6% at frequency range 2.3-2.58 GHz and 4.76-6.34 GHz, respectively.

Trapezoid-stub fed rectangular slot antenna for WLAN and WiMAX applications

This paper proposes the design of slot antenna for wideband use in wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. The antenna structure is comprised of a rectangular slot antenna and excited microstrip transmission line. The antenna is designed on low cost FR4 substrate and the simulation results are analyzed by IE3D Zeland software. The trapezoid tuning stub at the end of the microstrip line is proposed for decreasing return loss between frequency range 2.27 GHz to 6.21 GHz. The simulation result of return loss of the proposed antenna is shown that the operating bandwidth at frequency range of 2.27-6.21 GHz coverage standard of IEEE 802.11 b/g/j/a/h in WLAN (2.4-2.4835 GHz, 4.9-5.1 GHz, 5.15-5.35 GHz, 5.7-5.9 GHz) and WiMAX (2.5-2.7 GHz, 3.4-3.6. 5.7-5.9 GHz). The characteristics of antenna are proposed and analyzed for return loss, input impedance, bandwidth, VSWR, gain, and radiation pattern.

An IIR digital video equalizer design with the Bernstein Polynomial and generalized bilinear transformation for gain chrominance distortion

Video equalizer design for compensated the distortion of the chrominance amplitude in color television transmission system is presented. The approximation is based on the Bernstein polynomials and generalized bilinear transformation to obtain the transfer function. This approach has several parameters can be varied satisfying stability conditions. And the advantages of the Bernstein polynomials when compared to the Butterworth, Chebyshev and Thomson polynomials are three parameters available control the amount of phase and magnitude, linear phase, and flexible for variable of phase. Among all referred advantages so that these methodologies were applied in this paper. In addition, the pulse and bar test signal which has been used to measure linear waveform distortion in TV system is special the modulated 20T sine squared pulse with color sub-carrier 4.43 MHz for PAL system. As a result, the proposed digital video equalizer can be enhance and compress the gain chrominance distortion without degraded it phase characteristic.

CPW-fed slot antenna with inset U-strip tuning stub for wideband

The coplanar waveguide fed slot antenna with inset U-strip tuning stub is proposed for wideband applications. The antenna consists of rectangular slots with conductor tuning stub fed by CPW feed line. This antenna is design for match impedance with 50 ohm of characteristic impedance of transmission line. By adjusting dimension of inset U-strip tuning stub, the range of bandwidth can be achieved from 1.66 GHz to 7.22 GHz which can operate in WLAN (Wireless Local Area Network) according to IEEE 802.11 a/b/g standards and covered the WiMAX (Worldwide Interoperability for Microwave Access, IEEE 802.16e) and can operate for mobile GSM1800, GSM 1900. The characteristics of antenna are proposed and analyzed for instance input impedance, return loss, bandwidth, VSWR, and far field radiation patterns.

Performance comparison of adaptive algorithms for multiple echo cancellation in telephone network

In this paper presents the comparison of the performance of the variable step-size LMS adaptive algorithm and the fixed step-size LMS adaptive algorithm for cancels multiple echoes signal in telephone networks. The core of this paper is a multiple delay estimator, which estimates and distributes delays to each individual fixed length short echo canceller. It is shown that the variable step-size LMS adaptive algorithm yields the performances over the fixed step-size LMS algorithm. Computer simulation results are provided to confirm the performances of the variable step-size LMS algorithm.

Variable step-size modified MNG algorithm for adaptive IIR notch filter for detection of sinusoids

In this paper proposes an addition of a variable step-size modified memoryless nonlinear gradient (MNG) algorithm for a second-order adaptive IIR notch filter for detection of sinusoids in noise environment. The structure of the adaptive IIR notch filter is based on direct form structure and lattice form structure. The objective of variable step-size (VSS) algorithm is to optimize the filter coefficient. The computer simulation results are shown that the proposed algorithm provides fast convergence speed, low mean square error, low variance of filter coefficients and high impulsive noise robustness.