Multi-channel Power Research Articles

A programmable, multichannel power supply for SIPMs with temperature compensation loop and Ethernet interface

Among the different techniques available, the SiPM power supply described in this paper uses output voltage and sensor temperature feedback. A high-resolution ADC digitizes both the output voltage and an analog signal proportional to the SiPM temperature for each of its 16 independent outputs. The appropriate change in the bias voltage is computed in a micro-controller and this correction is applied via a high resolution DAC to the control input of a DC/DC module that produces the output voltage. This method allows a reduction in gain variations from typically 30% to only 0.5% in a 10 °C range. The power supply is housed in a 3U-height aluminum box. A 2.8'' touch screen on the front panel provides local access to the configuration and monitoring functions using a graphical interface. The unit has an Ethernet interface on its rear side to provide remote operation and integration in slow control systems using the encrypted and secure SSH protocol. A LabVIEW application with SSH interface has been designed to operate the power supply from a remote computer. The power supply has good characteristics, such as 85 V output range with 1 mV resolution and stability better than 2 mVP, excellent output load regulation and programmable rise and fall voltage ramps. Commercial power supplies from well-known manufacturers can show far better specifications though can also result in an over featured and over costly solution for typical applications.

Multiple omnidirectional defect modes and nonlinear magnetic-field effects in metamaterial photonic superlattices with a polaritonic defect

We report the existence of multiple omnidirectional defect modes in the zero-n¯ gap of photonic stacks, made of alternate layers of conventional dielectric and double-negative metamaterial, with a polaritonic defect layer. In the case of nonlinear magnetic metamaterials, the optical bistability phenomenon leads to switching from negligible to perfect transmission around these defect modes. We hope these findings have potential applications in the design and development of multichannel optical filters, power limiters, optical-diodes and optical-transistors.

Development and performance of a suprathermal electron spectrometer to study auroral precipitations.

The design, development, and performance of Medium-energy Electron SPectrometer (MESP), dedicated to the in situ observation of suprathermal electrons in the auroral ionosphere, are summarized in this paper. MESP employs a permanent magnet filter with a light tight structure to select electrons with proper energies guided to the detectors. A combination of two avalanche photodiodes and a large area solid-state detector (SSD) provided 46 total energy bins (1 keV resolution for 3-20 keV range for APDs, and 7 keV resolution for >20 keV range for SSDs). Multi-channel ultra-low power application-specific integrated circuits are also verified for the flight operation to read-out and analyze the detector signals. MESP was launched from Poker Flat Research Range on 3 March 2014 as a part of ground-to-rocket electrodynamics-electrons correlative experiment (GREECE) mission. MESP successfully measured the precipitating electrons from 3 to 120 keV in 120-ms time resolution and characterized the features of suprathermal distributions associated with auroral arcs throughout the flight. The measured electrons were showing the inverted-V type spectra, consistent with the past measurements. In addition, investigations of the suprathermal electron population indicated the existence of the energetic non-thermal distribution corresponding to the brightest aurora.

A hardware–software complex for controlling the pulsed power source of the T-15U tokamak

Results of designing of the hardware complex intended to control pulsed power systems of the T-15U tokamak are considered. The complex is based on digital and microprocessor components and ensures control over the power circuit of high-power semiconductor converters, monitoring of load parameters, and emergency protection of the electrical equipment. The complex is optimized for application in distributed multichannel power systems in which it is important that a group of converters operate synchronously into a complicatedly configured load.

Ultra-compact 1 × 8 Channel terahertz Wave Power Splitter

Relying on 1 × 2 photonic crystal waveguide and photonic crystal resonator, a compact eight-channel terahertz wave power splitter is proposed. The mechanism of such a device is further theoretically analyzed and numerically investigated with the aid of the plane wave expansion method and the finite-difference time-domain method. With an appropriate design, the proposed power splitter can split the input terahertz wave energy equally into eight output ports at the frequency of 0.667 THz. Furthermore, the total size of the present device is of 4.33 mm × 3.74 mm. Due to its small size, the multi-channel terahertz wave power splitter has practical applications in the terahertz wave integrated circuit fields.

Multi-channel programmable power supply with temperature compensation for silicon sensors.

Silicon Photo-Multipliers (SiPMs) are increasingly becoming popular for discrete photon counting applications due to the wealth of advantages they offer over conventional photo-detectors such as photo-multiplier tubes and hybrid photo-diodes. SiPMs are used in variety of applications ranging from high energy physics and nuclear physics experiments to medical diagnostics. The gain of a SiPM is directly proportional to the difference between applied and breakdown voltage of the device. However, the breakdown voltage depends critically on the ambient temperature and has a large temperature co-efficient in the range of 40-60 mV/°C resulting in a typical gain variation of 3%-5%/°C [Dinu et al., in IEEE Nuclear Science Symposium, Medical Imaging Conference and 17th Room Temperature Semiconductor Detector Workshop (IEEE, 2010), p. 215]. We plan to use the SiPM as a replacement for PMT in the cosmic ray experiment (GRAPES-3) at Ooty [Gupta et al., Nucl. Instrum. Methods Phys. Res., Sect. A 540, 311 (2005)]. There the SiPMs will be operated in an outdoor environment subjected to temperature variation of about 15 °C over a day. A gain variation of more than 50% was observed for such large variations in the temperature. To stabilize the gain of the SiPM under such operating conditions, a low-cost, multi-channel programmable power supply (0-90 V) was designed that simultaneously provides the bias voltage to 16 SiPMs. The programmable power supply (PPS) was designed to automatically adjust the operating voltage for each channel with a built-in closed loop temperature feedback mechanism. The PPS provides bias voltage with a precision of 6 mV and measures the load current with a precision of 1 nA. Using this PPS, a gain stability of 0.5% for SiPM (Hamamatsu, S10931-050P) has been demonstrated over a wide temperature range of 15 °C. The design methodology of the PPS system, its validation, and the results of the tests carried out on the SiPM is presented in this article. The proposed design also has the capability of gain stabilization of devices with non-linear thermal response.

Real Time Fear Detection Using Wearable Single Channel Electroencephalogram

Real time detection of emotional state has multiple applications for security, safety and identification of dangerous situations. Traditionally electroencephalogram (EEG) based emotion studies are conducted in controlled lab environment with multi-channel systems and large signal processing power. In order to be useful in real world situation the system for emotion detection has to be miniature, portable and working in real time supported by calculations that can be provided by a processor power of a mobile phone. Here we present our results on real time fear detection using portable single electrode EEG system conducted on 10 subjects. We studied possibility of translation of the markers previously identified for complex multi-electrode system - ratios of slow waves to fast waves into real time portable system. It was demonstrated using Student’s t-test that the average value of the monitored parameter during normal state was significantly higher than that of during a scary stimulus with a P value of (0.027) ~ 0.03 for Theta/ Beta. The framework for portable fear detection together with the markers discussed in this study can enable many applications important for the soldiers in the battlefield or police officers while being under attack as an indicator that help is urgently needed.

Effective Diversity Gain Evaluation for Large-Scale MIMO Antenna System

The success of multiple-input–multiple-output (MIMO) technology has lured substantial studies on devising large-scale MIMO antenna systems, which shall yield a higher throughput in a multipath-rich environment. However, the lack of measurement measures applicable to diversity assessment of antennas in a large number may hinder the design process. In this letter, an effective diversity gain measurement approach is proposed. The system comprises a multichannel data acquisition card and RF power detectors. It can be expanded to accommodate tens of antennas, and the data sampling process can be executed in a timely fashion. Results of several multiantenna designs are presented to validate the method effectiveness. On top of diversity assessment, performance features also include evaluations of antenna radiation efficiency and propagation environment characteristics.

A multichannel diffuse power estimator for dereverberation in the presence of multiple sources

Using a recently proposed informed spatial filter, it is possible to effectively and robustly reduce reverberation from speech signals captured in noisy environments using multiple microphones. Late reverberation can be modeled by a diffuse sound field with a time-varying power spectral density (PSD). To attain reverberation reduction using this spatial filter, an accurate estimate of the diffuse sound PSD is required. In this work, a method is proposed to estimate the diffuse sound PSD from a set of reference signals by blocking the direct signal components. By considering multiple plane waves in the signal model to describe the direct sound, the method is suitable in the presence of multiple simultaneously active speakers. The proposed diffuse sound PSD estimator is analyzed and compared to existing estimators. In addition, the performance of the spatial filter computed with the diffuse sound PSD estimate is analyzed using simulated and measured room impulse responses in noisy environments with stationary noise and non-stationary babble noise.

Multichannel Distribution Meter: A Veritable Solution in Power Distribution and Theft Prevention in Congested Environments

Power theft in partitioned commercial apartments, especially in the form of unpaid bills due to disputes, is a major challenge to revenue recovery in the power sector. This paper presents a multi-channel power distribution metering solution that serves to resolve disputes among users in partitioned apartments, and between the power distribution company and the end users of electricity. Partitioned apartments in commercial buildings particularly in congested environments shares energy supply meters among several users. This often leads to disputes and results to power theft in the form of unpaid bills and meter tampering. This paper described how power from a single supply meter can be adequately shared among a number of users with dispute arbitration. Each user’s channel is fed, monitored and controlled from a central unit which calculate and display energy usage, per unit cost and amount in cash consumed per channel. Compliant/non-compliant channel are connected/disconnected through a remote wireless access. It is envisaged that the use of this method for electricity distribution in commercial apartments, will greatly reduce power theft and increase revenue generation for the power industry. It will also eliminate disputes and possible litigations for the power industry and among users. http://dx.doi.org/10.4314/njt.v34i4.25

Tunable multi-channel terahertz wave power splitter

The combination of terahertz technology and photonic crystal provides a new approach to realize compact terahertz wave devices. Relying on a conventional photonic crystal waveguide and photonic crystal surface-mode waveguides, a tunable multi-channel terahertz-wave power splitter is proposed. The mechanism of such a power splitter is further theoretically analyzed and numerically investigated with the aid of the plane-wave-expansion method and the finite-difference time-domain method. With an appropriate design, the proposed device can split the input terahertz wave energy equally into six output ports at the frequency of 0.6THz. When changing the external magnetic field, the input terahertz wave can be equally divided into four output ports with the aid of a magnetic-sensitive material. Furthermore, the present device is very compact and the total size is of 4.4×6.0mm2.

End-to-End Route Reliability in Pervasive Multi-Channel Multi-Radio (PMCMR) Scheme for MANETS

Multi-channel multi radio wireless communications technologies have changed the trend of traditional routing based Quality of Service (QoS) in wireless-mesh networks. This avalanche of growth in multimedia communication is trigged by Multi-Channel Multi-Radio Wireless Mesh Networks (MCMR-WMNs). It is forecasted that in the near future, societal networks will have latest state of the art radio devices with Multi Channel and Multi Radio (MCMR) communication power with enhanced reliability, throughput and self-healing features. Despite of marked improvements in data link layer and physical layer in the IEEE 802.11 standards, optimized throughput, performance and network availability of MCMR wireless mesh networks still depend upon the efficient routing metric or protocol. We carried out a set of experiment and observed that cross layer routing in mesh networks is highly influenced by traffic load, interference between channel and interference between nodes. Proposed scheme used ‘conjugate distribution method’ which was designed to evaluate end-to-end route and communication reliability using posterior distribution function. Routing metric is evaluated based on load aware, intra and inter-interface aware, packet average delivery ration, latency and overhead with considered criteria of average path length. Competitive study revealed that proposed technique is efficient and applicable especial in environment where end-to-end reliability is required.

Quantitative analysis of transcranial and intraparenchymal light penetration in human cadaver brain tissue.

Photobiomodulation (PBM) also known as low-level light therapy has been used successfully for the treatment of injury and disease of the nervous system. The use of PBM to treat injury and diseases of the brain requires an in-depth understanding of light propagation through tissues including scalp, skull, meninges, and brain. This study investigated the light penetration gradients in the human cadaver brain using a Transcranial Laser System with a 30 mm diameter beam of 808 nm wavelength light. In addition, the wavelength-dependence of light scatter and absorbance in intraparenchymal brain tissue using 660, 808, and 940 nm wavelengths was investigated. Intact human cadaver heads (n = 8) were obtained for measurement of light propagation through the scalp/skull/meninges and into brain tissue. The cadaver heads were sectioned in either the transverse or mid-sagittal. The sectioned head was mounted into a cranial fixture with an 808 nm wavelength laser system illuminating the head from beneath with either pulsed-wave (PW) or continuous-wave (CW) laser light. A linear array of nine isotropic optical fibers on a 5 mm pitch was inserted into the brain tissue along the optical axis of the beam. Light collected from each fiber was delivered to a multichannel power meter. As the array was lowered into the tissue, the power from each probe was recorded at 5 mm increments until the inner aspect of the dura mater was reached. Intraparenchymal light penetration measurements were made by delivering a series of wavelengths (660, 808, and 940 nm) through a separate optical fiber within the array, which was offset from the array line by 5 mm. Local light penetration was determined and compared across the selected wavelengths. Unfixed cadaver brains provide good anatomical localization and reliable measurements of light scatter and penetration in the CNS tissues. Transcranial application of 808 nm wavelength light penetrated the scalp, skull, meninges, and brain to a depth of approximately 40 mm with an effective attenuation coefficient for the system of 2.22 cm(-1) . No differences were observed in the results between the PW and CW laser light. The intraparenchymal studies demonstrated less absorption and scattering for the 808 nm wavelength light compared to the 660 or 940 nm wavelengths. Transcranial light measurements of unfixed human cadaver brains allowed for determinations of light penetration variables. While unfixed human cadaver studies do not reflect all the conditions seen in the living condition, comparisons of light scatter and penetration and estimates of fluence levels can be used to establish further clinical dosing. The 808 nm wavelength light demonstrated superior CNS tissue penetration.

The Effect of High Power at Microwave Frequencies on the Linearity of Non-Polar Dielectrics in Space RF component

In satellite communication systems, there are high power multichannel transmitters and wideband receivers that have shared RF antenna transmission lines because of: 1) large power level difference between the transmitted and received signal; 2) limited frequency channels. The harmonics and Passive Intermodulation (PIM) Interference will be generated due to passive non-linearities in the high power transmission path. This can be a serious problem. This paper describes how to determine the signal levels and dominant mechanisms that are associated with non-linear dielectric behavior in this context. A novel measurement system for testing dielectric samples is described and measurement results are provided for commonly used microwave dielectrics.

Features of construction of multichannel intellectual power packs

A series of aspects on the development of apparatus tools from modern multichannel intellectual power packs (MIPPs) is considered. A new microcircuit for the protection of the power pack against the over-load with respect to the current and temperature is developed.

Phase locking of a seven-channel continuous wave fibre laser system by a stochastic parallel gradient algorithm

A seven-channel fibre laser system operated by the master oscillator – multichannel power amplifier scheme is the phase locked using a stochastic parallel gradient algorithm. The phase modulators on lithium niobate crystals are controlled by a multichannel electronic unit with the microcontroller processing signals in real time. The dynamic phase locking of the laser system with the bandwidth of is demonstrated, the time of phasing is .

PO-1014 Effect Of Laser Acupuncture On The Immunomodulatory Parameters In Asthmatic Children And Its Relation To Asthma Improvement

Background and aims LASER acupuncture has often been recommended as a treatment of asthma. The technique is noninvasive, and suitable for children. Acupuncture has been shown to have an immediate effect on relieving the symptoms of asthma. Few studies have demonstrated that acupuncture has beneficial clinical and physiologic effects on asthma, including the immunomodulatory effects of inflammatory cells and cytokines. Our aim is to study the effect of low power multichannel laser acupuncture in the improvement of asthmatic children and its relation to changes in their immunomodulatory system (IgE- Interlukin-4). Methods 20 cases of asthmatic children (7–15years) were subjected to 12 laser acupuncture sessions in acupuncture points selected for asthma according to traditional Chinese medicine 3 times per week. Clinical improvement and medications used were recorded, IL-4, IgE were measured (ELISA technique), Eosinophilic count and pulmonary functions were done before and after sessions. Results There were a significant improvement in some parameters of pulmonary functions before and after laser acupuncture sessions in comparing to using of conventional medical treatment only (FVC p Conclusion Uses of laser acupuncture in accompanied with conventional medical treatment is more effective in controlling of asthmatic children than using conventional medical treatment only and also accompanied with improvement of all IL-4, IgE and pulmonary functions.

A Low-Voltage Distribution Box with Energy Monitoring and Carrier Communication Functions

A low-voltage distribution box with both energy monitoring and carrier communication capability is developed to collect , store and transmit multi-channel current, voltage , power, and electrical degree surveillance and other information, and the detail of its hardware design is described, ARM9 chip is used as a microcontroller, AD8364 with six channels is applied to ensure the speed and accuracy of data acquisition, the carrier chip ST7538 is adopted to transmit the acquired information to concentrator at specific time. The investment cost of the distribution box is low, and easy to be installed and maintained, and can be widely used in various industries for middle and small-sized enterprises.

Design and Application of Multichannel Peristaltic Acceleration Pulsed Plasma Power Supply

Based on the continuous and microsecond pulsed plasma power supply, a multichannel peristaltic acceleration pulsed plasma power supply is developed. The overall design ideas and system block diagram are proposed. Additional modulation functions of pulsed phase angle, duty cycle ratio, and pulsed frequency are implemented to improve the control capability of the plasma actuation for flow control. Long time running results show that this power supply can generate good waveform and smooth plasma discharge. It meets the requirements of plasma discharge for various means of flow control, such as continuous, pulsed, duty cycle, and peristaltic acceleration plasma actuation. Finally, successful wind-tunnel experiments for plasma flow control over a slender body at high angle of attack by using this power supply is conducted. It shows that the plasma actuation excited by the power supply provides the highly needed lateral force and moment control on slender body at high angles of attack, without the unpredictable onset of asymmetric aerodynamic loads.

Adaptive Multi-Channel Transmission Power Control for Industrial Wireless Instrumentation

The adoption of wireless technology for industrial wireless instrumentation requires high-quality communication performance. The use of transmission power control (TPC) can help address industrial issues concerning energy consumption, interference, and fading. This paper presents a TPC algorithm designed for industrial applications based on theoretical and empirical studies. It is shown that the proposed algorithm adapts to variations in link quality, and is hardware-independent and practical.