Transmitter Unit Research Articles

A Miniaturized Contactless UWB Microwave System for Time-Domain Dielectric Spectroscopy

A miniaturized time-domain (TD) dielectric spectroscopy system for contactless material characterization over the ultra-wideband (UWB) microwave range is presented in this paper. The proposed system includes a transmitter, a compact contactless sensing unit, and a receiver. A picosecond pulse generator unit in the transmitter delivers a quasi-monocycle pulse with 3.5-GHz 10-dB bandwidth to an up-converter and then an amplifier. The generated pulse provides the capability to perform the material characterization in a fast pure TD fashion. The transmitter unit provides the 3–10-GHz excitation pulse based on utilizing a direct up-conversion architecture. The excitation pulse is transmitted to the receiver through the sensing unit. Two Vivaldi antennas are coupled to each other in their radiative near field to construct the sensing unit, while the material-under-test (MUT) is placed in between. A custom-designed Quartz-Glass cuvette is utilized with optimized MUT volume of ~5 mL. The TD data are captured for each MUT using DSA91304A infiniium oscilloscope as the receiver, and finally the fast Fourier transform of the measured data is extracted in MATLAB. A calibration procedure is discussed to achieve a behavioral model of the system using seven calibration MUTs. From there, the $\epsilon '$ and $\epsilon ''$ characterization of three unknown MUTs are carried out. The system shows the worst case mean-squared error (MSE) of 1.92% for $\epsilon '$ and 3.84% for $\epsilon ''$ characterization. Furthermore, binary mixture detection based on $\epsilon '$ accomplished with the MSE of 2.74%.

A fiber-optic analog isolator of up to 10 MHz bandwidth

The electromagnetic interference (EMI) around the Experimental Advanced Superconducting Tokamak (EAST) device is very harsh during plasma discharge experiment. In order to reduce the effect of EMI and enhance signal to noise ratio (SNR), a fiber-optic high speed isolator has been designed. Each channel of the isolator has a transmitter unit connected via fiber-optic cable to the receiver unit. A transmitter unit which consists of a 6th order Bessel low-pass anti-aliasing filter, an analog-to-digital converter (ADC), a Field Programmable Gate Array (FPGA), a serializer and an optical transceiver, while a receiver unit comprises an optical transceiver, a deserializer, a FPGA, a digital–to-analog converter (DAC) and a 6th order Bessel low-pass filter. Data from the ADC is serialized by the serializer using 8b/10b encoding before transmission, and 10b/8b decoding was used by the deserializer in the receiver unit. A prototype of this isolator has been realized and tested. The test results show that the transmission bandwidth of analog signal is up to 10MHz, the transmission delay is typically 500ns, the transmission distance is up to 250m and the output noise is less than 5mV, which can meet the requirements of EAST experimental campaigns.

An embedded multi-sensor system on the rotating dynamometer for real-time condition monitoring in milling

The newly developed multi-sensor system for a milling process sensor system is capable of simultaneously measuring six channels of machining signals using a rotating tool incorporating a wireless system. Furthermore, the system can be used to measure the spindle torque, T q ; tool vibration in the z-axis, A z ; tool tip temperature, T m and the three components of the cutting force. Cutting force signals are generated by using a cross-beam-legged transducer embedded in the standard milling tool holder. A mini accelerometer is placed under the force transducer, whereas a thermocouple is positioned under a cutting tool insert close to the cutting edge. All signals are collected and sent to the data logger system via an inductive wireless transmitter unit incorporated into the standard rotating tool holder. The calibration, verification and real experimental machining test results reveal that the sensor system is both suitable and reliable for measuring machining signals. The measured signals are found to be importantly related to changes in the flank wear state. Therefore, this system can be used for real-time tool condition monitoring in the milling process.

High-Frequency Properties of Fe-4.5 Wt% Si Powders With an Insulating Layer Synthesized by a Modified Dew-Point Treatment

The frequency for wireless power chargers is in the range of 100–205 kHz when using MnZn ferrite and NiZn ferrite. Compared to ferromagnetic metals, these ferrites have higher resistivity, which reduces the eddy loss at high frequencies, though they also have lower magnetization values that limit the distance and the direction between the receiver and transmitter units. Thus, there is a strong demand for the development of a new metallic magnetic sheet that can suppress the eddy-current loss in the high-frequency range. To meet this demand, a modified dew-point insulation coating method for Fe-4.5 wt% Si powders was assessed and the high-frequency properties of green compacts consisting of these powders were investigated. As a result, a thin high-resistivity layer was successfully coated onto the powders. In addition, both eddy-current loss and hysteresis loss of their compacts were dramatically reduced in the high-frequency region.

Portable broadband cavity-enhanced spectrometer utilizing Kalman filtering: application to real-time, in situ monitoring of glyoxal and nitrogen dioxide

This article describes the development and field application of a portable broadband cavity enhanced spectrometer (BBCES) operating in the spectral range of 440-480 nm for sensitive, real-time, in situ measurement of ambient glyoxal (CHOCHO) and nitrogen dioxide (NO2). The instrument utilized a custom cage system in which the same SMA collimators were used in the transmitter and receiver units for coupling the LED light into the cavity and collecting the light transmitted through the cavity. This configuration realised a compact and stable optical system that could be easily aligned. The dimensions and mass of the optical layer were 676 × 74 × 86 mm3 and 4.5 kg, respectively. The cavity base length was about 42 cm. The mirror reflectivity at λ = 460 nm was determined to be 0.9998, giving an effective absorption pathlength of 2.26 km. The demonstrated measurement precisions (1σ) over 60 s were 28 and 50 pptv for CHOCHO and NO2 and the respective accuracies were 5% and 4%. By applying a Kalman adaptive filter to the retrieved concentrations, the measurement precisions of CHOCHO and NO2 were improved to 8 pptv and 40 pptv in 21 s.

An accurate technique of measurement of flow rate using rotameter as a primary sensor and an improved op-amp based network

In the present paper, a simple rotameter transmitter has been studied using an inductive coil in differential form as a secondary sensor and rotameter as the primary sensor. The proposed technique measures the flow rate and converts the flow rate variation into an electrical current which can be easily transmitted to a remote location like a control room. The change in inductance due to change in flow rate is measured by an improved op-amp inductance based network. The proposed prototype transmitter unit has been designed and developed and then its theory of operation has been derived. The performance of the developed transducer has been experimentally studied and the experimental results are reported in the paper. The experimental result appears to follow the theoretical equations with very good linearity and repeatability with very small uncertainty in measurement. The graphical abstract is shown below.

Analysis of Atmospheric Turbulence on Free Space Optical System using Homotopy Perturbation Method

AbstractFree Space Optics (FSO) is a wireless optical communication technology which depends on propagation of optical beam through air. FSO communication system provides secure communication link, cost-effective solution and license-free operation. In this paper, the FSO communication link has been analysed in turbulent atmosphere using homotopy perturbation method (HPM). We have designed a FSO system operating at an optical wavelength of 850 nm with a signal power of 4 dBm having a link range of 2 km between transmitter and receiver unit. It has been observed that in atmospheric turbulence high performance FSO link is achieved by increasing the aperture diameter of receiver telescope.

High-Accuracy Localization Platform Using Asynchronous Time Difference of Arrival Technology

Despite extensive research efforts on ranging and localization modeling and simulation, research on practical implementations is limited. For the first time, a complete prototype based on asynchronous time difference of arrival (A-TDOA) technique is implemented in hardware. The A-TDOA technique requires neither clock synchronization between a target and anchor nodes nor wired infrastructure among anchor nodes, both of which are necessary for time of arrival and TDOA systems, respectively. All subsystems, including transmitter, receiver, antenna, and baseband processing unit, are developed from scratch and undergone significant updates for improved reliability. The implemented system has been extensively tested in an outdoor and indoor line of sight radio environments, and the accuracies obtained are 20.7 and 15.2 cm in $8 \,\text{m} \times 8 \,\text{m}$ and $6 \,\text{m}\times 6 \,\text{m}$ areas, respectively. In nonline of sight indoor environment, the achieved accuracy is 21.3 cm in $5 \,\text{m}\times 5 \,\text{m}$ area. The comparison with the literature published to date proves the excellent quality of these results. To better understand the localization accuracy, the error sources due to thermal noise, hardware limitation, and radio propagation channel are identified and investigated. Mitigation methods are proposed to reduce errors. The implemented prototype supports many unique applications including cargo tracking, tourist guiding, emergency evacuation, and so on.

Embedded digital drive wheel torque indicator for agricultural 2WD tractors

A microcontroller based embedded system was developed to measure and display the dynamic wheel axle torque and drawbar power of agricultural tractor for tillage research. The device includes a special transducer to measure dynamic drive wheel torque of tractor, an embedded wireless digital system to receive process and display data digitally as well as record in SD card module near the dash board of the tractor. The embedded system mainly consists of an amplifier to amplify the transducer signal, a transmitter unit to process the amplifier data, and a receiver unit to receive and display the transmitter unit data. The developed system was rigorously tested under laboratory and actual field conditions. It was found that, a maximum variation of ±320Nm torque between the theoretically calculated and experimentally observed values under field conditions. With the developed devices the real time power requirement of various agricultural operations could be known to help the tillage researchers. The developed device and systems are simple and accurate and can be used for any range of agricultural tractors.

DESIGN AND IMPLEMENTATION OF A RESONANT WIRELESS POWER TRANSMISSION SYSTEM BASED ON A SELF OSCILATING D.C-A.C CONVERTER

Abstract. In the present work a complete wireless power system, composed by two identical units (Transmitter and Receiver) and a Power Electronic Converter (PEC), was designed and built. Receiver unit is constituted of two wire coils, drive coil (DC) and main coil (MC), while transmitter unit have only a MC. In transmitter unit the MC is connected to the PEC. In the receiver unit the DC is connected to a load of 1kΩ and inductively coupled to the MC. DC has one turn and MC ten turns with 8.3894 H. As the natural capacitance of each MC is very small, a capacitor was solder in parallel with each MC to reduce the resonant frequency to about 1.3MHz. The PEC is a self-oscillating DC-AC power converter projected to work in the range from 800kHz to 3MHz. Keywords: Wireless Power Transmission, Self-Oscillating Converter, Inductive Coupling

Assessing Reactive Strength Measures in Jumping and Hopping Using the Optojump™ System.

The aim of this study was to assess the concurrent validity of the Optojump™ system (Microgate, Bolzano, Italy) versus a force platform in the estimation of temporal and reactive strength measures. In two separate investigations, twenty physically active males performed double-leg and single-leg drop jumps from a box height of 0.3 m and a 10 s vertical bilateral hopping test. Contact time, flight time and total time (the sum of contact and flight time) were concurrently assessed during single and double-leg drop jumps and during hopping. Jump height, the reactive strength index and the reactive strength ratio were also calculated from contact time and flight time. Despite intraclass correlation coefficients (ICCs) for all variables being close to 1 (ICC > 0.975), a significant overestimation was found in contact time (0.005 ± 0.002 s) and underestimations in flight time (0.005 ± 0.003 s), the reactive strength index (0.04 ± 0.02 m·s-1) and the reactive strength ratio (0.07 ± 0.04). Overestimations in contact time and underestimations in flight time were attributed to the physical design of the Optojump™ system as the transmitter and receiver units were positioned 0.003 m above the floor level. The Optojump™ demonstrated excellent overall temporal validity with no differences found between systems for total time. Coaches are advised to be consistent with the instrumentation used to assess athletes, however, in the case of comparison between reactive strength values collected with the Optojump™ and values collected with a force platform, regression equations are provided.

Microwave Measurement System for Detection of Dielectric Objects in Powders

Detection and removal of undesirable objects is an important issue in many material processing industries. This paper presents a microwave-based measurement technique for detection of dielectric objects in powder materials flowing through metal pipes. A nonintrusive microwave sensor is developed, which uses multiple resonant modes to obtain high sensitivity with respect to permittivity variations inside the pipe. Undesirable objects are detected based on the scattering parameters of the sensor, which are measured using a fast-sampling microwave transmitter and receiver unit. We present a detection algorithm derived from the likelihood-ratio test, which includes a parametric model of the local statistical distribution of the measured scattering parameter data. The model involves a set of Mobius transformations that map the measured scattering parameters to a domain where the data are Gaussian distributed. All unknown parameters in the model are estimated from data using maximum likelihood. Based on measurement results from a gravity-fall experimental setup, we conclude that small dielectric objects can be reliably detected in heterogeneous flows of dielectric powder.

A Review on an Efficient Monitoring Of Substations Using Microcontroller Based Monitoring System

The paper presents review on innovative design to develop a system based on AVR micro controller that is used for monitoring the voltage, current and temperature of a distribution transformer in a substation and to protect the system from the rise in mentioned parameters. Providing the protection to the distribution transformer can be accomplished by shutting down the entire unit with the aid of the Radio frequency Communication. Moreover the system displays the same on a PC at the main station which is at a remote place. Furthermore it is capable of recognizing the break downs caused due to overload, high temperature and over voltage. The design generally consists of two units, one in the substation unit, called as transmitter and display unit, and another in the Main station called as controlling unit. The transmitter and the display units in the substation is where the voltage, current and temperature are monitored continuously by AVR microcontroller and is displayed through the display unit. An RF transmitter is used for transmitting the signals that are obtained. The controlling unit in the main station by means of a PC and a RF receiver receives the RF signals that are transmitted by the Transmitter unit and reacts in accordance to the received signal. In general, the proposed design is developed for the user to easily recognize the distribution transformer that is suffered by any open or short circuit and rise in temperatures. The ultimate objective is to monitor the electrical parameters continuously and hence to guard the burning of distribution transformer or power transformer due to the constraints such as overload, over temperature and input high voltage. If any of these values increases beyond the limit then the entire unit is shut

Wireless Multichannel Neural Recording With a 128-Mbps UWB Transmitter for an Implantable Brain-Machine Interfaces.

Simultaneous recordings of neural activity at large scale, in the long term and under bio-safety conditions, can provide essential data. These data can be used to advance the technology for brain-machine interfaces in clinical applications, and to understand brain function. For this purpose, we present a new multichannel neural recording system that can record up to 4096-channel (ch) electrocorticogram data by multiple connections of customized application-specific integrated circuits (ASICs). The ASIC includes 64-ch low-noise amplifiers, analog time-division multiplexers, and 12-bit successive approximation register ADCs. Recorded data sampled at a rate of 1 kS/s are multiplexed with time division via an integrated multiplex board, and in total 51.2 Mbps of raw data for 4096 ch are generated. This system has an ultra-wideband (UWB) wireless unit for transmitting the recorded neural signals. The ASICs, multiplex boards, and UWB transmitter unit are designed with the aim of implanting them. From preliminary experiments with a human body-equivalent liquid phantom, we confirmed 4096-ch UWB wireless data transmission at 128 Mbps for distances below 20 mm .

Simultaneous and spatially separated detection of multiple orbital angular momentum states

We present a method for spatially separated detection of multiple orbital angular momentum (OAM) states, simultaneous. The starting point is the generation of axially superposed Laguerre–Gauss beams, carrying multiple OAM states using a single computer generated hologram. The information contained in the OAM superposition is transferred to the first diffraction order and is detected at the receiver with a reading mask, which contains two perpendicular superposed fork-like holograms, ensuring the spatial separation of the OAM states. The dynamic of the process is studied in terms of the number of generated OAM states and the constructive parameters values. The experimental investigations use an optical arrangement based on a spatial light modulator in the transmitter unit and an amplitude mask in the receiver unit. This proof of concept experiment demonstrates the possibility of simultaneously detection of multiple OAM states in points located at different coordinates, controlled through the design of the holograms and shows the capability of our proposed method to increase the capacity of free-space optical communication channels.

In-vitro Measurement of Glucose Concentration in Human Blood Plasma Mixed Intralipid Phantom Samples by Using Modulated Ultrasound and Infrared Light

Non-invasive blood glucose measurement is one of most innovative domain in Biomedical Engineering. Multiple methodologies have-been introduced over last few decades to fulfil the clinical requirement for non-invasive glucose measurement in human beings, however, without a successful breakthrough. This research article uses modulated ultrasound with infrared light-based technique to study glucose-induced variations in human blood plasma mixed Intralipid TM phantom samples using infrared light of 940 nm and 40 kHz central frequency based ultrasonic transmitter unit. The test uses blood samples of 30 study subjects during oral glucose tolerance test and fasting, postprandial and random stages based blood glucose tests respectively. The result as obtained from oral glucose tolerance tests and fasting, postprandial and random stages blood Original Research Article

25 Gb/s Silicon Photonics Interconnect Using a Transmitter Based on a Node-Matched-Diode Modulator

In this article a nonreturn-to-zero data transmission of 25 Gb/s between silicon photonic transmitter and receiver units is demonstrated, where the transmitter is based on a silicon optical Fabry–Perot modulator with a node-matched-diode geometry. This modulator type has a footprint of less than 100 μm2. On the receiver side, an integrated Ge-photo detector has been used. Mask tests according to the 100G ER4 standard have been performed and yielded error free data transmission.

Position Control Mathematical Modelling and Operational Evaluation of Tele-Operated Electro-Hydraulic Actuator (T-EHA)

This study deals with a master-slave system for a tele-operated electro-hydraulic actuator (T-EHA) that focuses on a hydraulic system to remotely control a mini excavator. Tele-operation using such system is useful for tele-operation support of heavy construction and road restoration, typically in post-disaster areas. This paper presents the current development of position control electro-hydraulic actuator for such remote tele-operation application. A 2.4 GHz radio-controlled transmitter and receiver unit, which is also known as the master, has been utilized as the remote controller for an electro-hydraulic actuator. The electro-hydraulic actuator, which serves as the slave has been fabricated by using a tie-rod cylinder, and coupled with a 24 VDC electro-hydraulic valve. Position control mathematical modelling and operational evaluation have been studied with regard to the tele-operated electro-hydraulic actuator.

PC Based Wireless Monitoring and Control of Fire Detection and Extinguishing System

Fire disaster is at present causing huge economic loss as well as tragedy of human death in a frequent manner. PC based wireless monitoring and control of fire detection and extinguishing system will provide real time monitoring and protection from fire to a great extent. In this paper, a pc based cost effective wireless monitoring and control of fire detection and extinguishing system has been designed and developed. The system is able to activate alarm and generate short message service (SMS) using GSM modem when fire is detected and also able to control the fire by unleashing the fire extinguisher (foam and water). It is made up of two sensors, computer interfacing board, system software and both gas and water extinguishers. The sensors have been integrated along with the transmitter to form a single unit using PCB design. The system has also a remote receiving unit to receive fire detection signal transmitted from the sensor through the transmitter unit. The receiver unit is connected to a PC through USB port. This signal is processed by LabVIEW software of National Instruments, USA, and also generate control signals to activate fire extinguishers and generate SMS to transmit through GSM modem which is connected to PC through USB port. The present system controls the whole process using a Virtual instrument developed in LabVIEW which provides a user friendly front panel on the PC screen that one can easily understand and operate. This kind of system is very cheap and flexible for any modification.

A Smart Cage With Uniform Wireless Power Distribution in 3D for Enabling Long-Term Experiments With Freely Moving Animals.

This paper presents a novel experimental chamber with uniform wireless power distribution in 3D for enabling long-term biomedical experiments with small freely moving animal subjects. The implemented power transmission chamber prototype is based on arrays of parallel resonators and multicoil inductive links, to form a novel and highly efficient wireless power transmission system. The power transmitter unit includes several identical resonators enclosed in a scalable array of overlapping square coils which are connected in parallel to provide uniform power distribution along x and y. Moreover, the proposed chamber uses two arrays of primary resonators, facing each other, and connected in parallel to achieve uniform power distribution along the z axis. Each surface includes 9 overlapped coils connected in parallel and implemented into two layers of FR4 printed circuit board. The chamber features a natural power localization mechanism, which simplifies its implementation and ease its operation by avoiding the need for active detection and control mechanisms. A single power surface based on the proposed approach can provide a power transfer efficiency (PTE) of 69% and a power delivered to the load (PDL) of 120 mW, for a separation distance of 4 cm, whereas the complete chamber prototype provides a uniform PTE of 59% and a PDL of 100 mW in 3D, everywhere inside the chamber with a size of 27×27×16 cm(3).