Separation of Digital Audio Signals using Least-Mean-Square (LMS) Adaptive Algorithm

Adaptive filtering is one of the fundamental technologies in digital signal processing (DSP) in today’s communication systems and it has been employed in a wide range of applications such as adaptive noise cancellation, adaptive equalization, and echo cancellation.Signal separation remains a task that has called for attention in digital signal processing and different techniques have been employed in order to achieve efficient and accurateresult. Implementation of adaptive filtering can separate wanted and interference signals so as to improve performance of communication systems. In the light of this, this paper usesa least-mean-square (LMS) adaptive algorithm for separation of audio signals.The simulated results show that the designed LMS based adaptive filtering techniqueconverge faster than conventional LMS adaptive filter.DOI:http://dx.doi.org/10.11591/ijece.v4i4.621

Voice-Based Door Access Control System Using the Mel Frequency Cepstrum Coefficients and Gaussian Mixture Model

Access to an area or environment can be controlled by conventional and electronic keys, identity cards, personal identification numbers (PINs) pads and smartcards.  Due to certain limitations of existing door access schemes deployed for security in buildings, this paper presents speaker recognition for building security as a better means of admission into important places. This is proposed due mainly to the fact that speech cannot be stolen, copied, forgotten, lost or guessed with accuracy. This paper, therefore presents design of an affordable voice activated door control system for building security. The proposed system uses the Mel Frequency Cepstrum and the Gaussian Mixture Model for feature extraction and template pattern matching respectively. The analysis of the result which is based on the false acceptance and rejection rates indicate a system accuracy of more than 80%.DOI:http://dx.doi.org/10.11591/ijece.v4i5.644

QUADRIFILAR HELIX ANTENNA FOR WEATHER SATELLITE RECEPTION

The study designed and implemented quadrifilar helix antenna (QHA) for weather satellite signal reception. The antenna design and optimization were done by varying the element diameter, the radial lengths, the axial lengths, and element materials on adopted model. The simulated QHA has far-field radiation pattern in the upper hemisphere with maximum gain of 4.14dBi at 0o and omnidirectional coverage, half-power beamwidth of 140o, bandwidth of 6.5MHz, and VSWR of 1.13. The implemented QHA has major lobe in conformity with the simulated QHA with maximum gain of 10.75dB at 0o, and half-power beamwidth of 104o

QUADRIFILAR HELIX ANTENNA FOR WEATHER SATELLITE RECEPTION

The study designed and implemented quadrifilar helix antenna (QHA) for weather satellite signal reception. The antenna design and optimization were done by varying the element diameter, the radial lengths, the axial lengths, and element materials on adopted model. The simulated QHA has far-field radiation pattern in the upper hemisphere with maximum gain of 4.14dBi at 0o and omnidirectional coverage, half-power beamwidth of 140o, bandwidth of 6.5MHz, and VSWR of 1.13. The implemented QHA has major lobe in conformity with the simulated QHA with maximum gain of 10.75dB at 0o, and half-power beamwidth of 104o

DESIGN ANALYSIS OF AN AUTOMATIC PHASE SELECTOR

Power instability in Nigeria caused by overbearing demand of power by consumers and lack of proper maintenance of the power system devices among others has brought about the need for alternative power sources such as generators, solar, typical inverters and other alternative supplies which requires one form of switching or the other to achieve phase selection during power failure. This paper gives a design analysis of an automatic phase selector linking available power supplies, that is; switching between a three-phase public utility supply, as a result of total power outage in the public supply to an alternative secondary supply (in this case a Generator and an Inverter system) and back when power is restored. The design adopts the use of a microcontroller-based system interconnected with other hardware components for proper isolation, switching and visualization of switching conditions. The system design is divided into two major part: the hardware which consists of the power supply, sensing circuit, controller or control logic circuit, display and the power electronics switching unit and the software instruction code on the microcontroller unit. The design analysis was first carried out accompanied with computer simulation on a software tool (Proteus 8 Professional, version 8.4) to carry out performance evaluation of the sub-circuits, thereafter, a practical implementation of the design was carried out and tested with the utility power supply using five (5) switches, three of which represents the three-phase primary supply and the other two represents the secondary supply

STABILITY CONTROL MODELLING UNDER DYNAMIC MOTION SCENARIO OF A DIFFERENTIAL DRIVE ROBOT

Intelligence incorporated in many devices makes it easier to achieve self-balancing and autonomous driving in differential drive robot. Basically, differential drive robotic system describes an unstable, nonlinear system related to an inverted pendulum. The research attempts to harness the parameters obtained from a computer-aided design tool (Solid works) to model the system for complete stability control and dynamic motion of the system within a planned trajectory. A linearized dynamic equation is obtained for the overall system design of a mobile robot, and the linear quadratic regulator concept is adopted to obtain an optimum state feedback gain. The simulation results are obtained on MATLAB software interfaced with an Arduino board with deployable sensor technologies. Scenarios of disturbance would be simulated to ascertain the stability conditions of the system at static position or dynamic position. Signal analysis and computer vision techniques serve as leverage to make the design achievable. Localization and navigation referred to as tracking a planned trajectory or moving through paths filled with obstacles in a given space are also included

QUADRIFILAR HELIX ANTENNA FOR WEATHER SATELLITE RECEPTION

The study designed and implemented quadrifilar helix antenna (QHA) for weather satellite signal reception. The antenna design and optimization were done by varying the element diameter, the radial lengths, the axial lengths, and element materials on adopted model. The simulated QHA has far-field radiation pattern in the upper hemisphere with maximum gain of 4.14dBi at 0o and omnidirectional coverage, half-power beamwidth of 140o, bandwidth of 6.5MHz, and VSWR of 1.13. The implemented QHA has major lobe in conformity with the simulated QHA with maximum gain of 10.75dB at 0o, and half-power beamwidth of 104o