Effects of Optical Beams on MIMO Visible Light Communication Channel Characteristics

Under 5G envision, for pushing visible light communication (VLC) channel model evolution to various non-Lambertian beams, this paper introduces the typical commercial non-Lambertian beams, such as Luxeon rebel and side emitter, into the conventional analytical VLC channel model. The numerical results illustrate that the non-Lambertian beams can significantly affect the VLC channel frequency response characteristics. Compared with the traditional Lambertian beam, Side Emitter optical beam could naturally bring up to about 56.8% VLC multi input multi output channel capacity deviation, which objectively opens a new discussion dimension for enhancing VLC transmission performance.

Control device synthesis by polynomial matrix fractional descriptions method with limitation on controller structure

Modification of the algorithm for the polynomial synthesis of a multi-channel controller was proposed to preserve all control channels in this article. In order to test the functionality of the proposed modification, an example of a linear model of an unstable multi-channel plant is considered. The choice of the plant was determined by the possibility of a visual algorithm demonstration for polynomial synthesis of the controller, taking into account the proposed modifications.The plant was represented as three series-connected standard links: an aperiodic link of the first order, an unstable link, and an integrator, and has three input and two output channels. The control in the system is carried out in the feedback of the system and is summed up with the input impact. The feature of the plant is to limit the task to the second output, since it is essentially a derivative of the first output. In addition, the plant has a direct input–output channel. That is, the traversal matrix of the system is nonzero (when described through the state space). The synthesis task was set as follows: it is necessary to achieve certain quality indicators of the output vector value while maintaining all three control channels of the plant.

Compensated Single Input Multiple Output Flyback Converter

A new single-input multiple-output (SIMO) converter is proposed in this work by incorporating flyback and buck converters in a master–slave configuration. The objective of this work is to address the cross regulation problem, achieve tight voltage regulation, improve the circuit form factor and attain a fast transient response for a SIMO flyback converter. The flyback converter maintains the output channels within 10% of their rated voltages and the SIMO buck converter is placed in series with the flyback converter such that it compensates for the output voltage deviation. Moreover, a time multiplexing switching scheme decouples output channel to eliminate the cross-regulation problem and remove the need for an additional winding transformer per each output channel. A type II compensator with a peak current mode controller was designed to achieve faster transient response which is critical for the proposed configuration. A thorough steady-state analysis was carried out on a triple output channel topology to obtain the design criteria and component values. MATLAB/Simscape modelling and simulation was used to validate the effectiveness of the proposed converter with the result yielding satisfactory transience even with load disturbance. Additionally, the result of the proposed converter is compared with previously published works.

Analisis Perbandingan Tingkat Tekanan Bunyi Terhadap Sistem Pembangkit Suara Akustik dengan Efek Surround dan Tanpa Efek Surround

<em>This study aims to determine the comparison of the sound pressure level produced by an acoustic sound generator system with surround effects without surround effects. Acoustic sound generating system with surround effects is designed and made as a sound system that produces a surround effect where the resulting sound is divided and distributed over two or many channels (multi channel). This sound system consists of four parts, namely: front cannel, rear surround channel, extra rear channel and subwoofer. This system gets input from the VCD in the form of R and L signals into the AN7397K IC then comes out through four output channels. Each output channel is connected to a 150 watt stereo and mono power amplifier. From the results of research with statistical tests using the t distribution shows that there is a difference in sound pressure level (SPL) between acoustic sound generating systems with surround effects without surround effects at a distance of 1 meter to 10 meters, where the value of the sound pressure level with a sound generator system is obtained. acoustics with a surround effect higher than the sound pressure level without a surround effect</em>

Physical simulation of thermomechanics of gas flows in the output channels of turbocharger centrifugal compressor

It is known that the thermal and mechanical characteristics of the air flow in the output channel of the turbocharger compressor largely determine the efficiency and quality of the gas exchange processes of the piston engine. The research was carried out on an experimental installation containing a turbocharger, output channels of different configurations, a measurement database and a data collection system. It was found that the stabilization of the flow in the output channel of the compressor leads to a significant increase in the heat transfer intensity (up to 25 %) compared to the base pipeline, while reducing the degree of turbulence by up to 30 %. In the output channel of the compressor with grooves, there is an even more significant increase in the heat transfer intensity (up to 30 %) with an increase in the degree of turbulence by up to 12% compared to the base channel. The proposed configurations of the compressor output channels can be used to intensify heat exchange in order to naturally cool the air during the intake process, as well as to stabilize the gas dynamic parameters of the flow in order to reduce the hydraulic resistance of the intake system of the turbocharged engine.