Types Of Transmitters Research Articles

Towards Coexistence of Cellular and WiFi Networks in Unlicensed Spectrum: A Neural Networks Based Approach

Long-Term Evolution in the Unlicensed Spectrum (LTE-U) is considered as an indispensable technology to mitigate the spectrum scarcity in wireless networks. Typical LTE transmissions are contention-free and centrally controlled by the Base Station (BS). However, the wireless networks that work in unlicensed bands use contention-based protocols for channel access, which raise the need to derive an efficient and fair coexistence mechanism among different radio access networks. In this paper, we propose a novel mechanism based on neural networks for the coexistence of an LTE-U BS in the unlicensed spectrum alongside with WiFi access points. Specifically, we model the problem in coexistence as a 2-Dimensions Hopfield Neural Network (2D-HNN) based optimization problem that aims to achieve fairness considering both the LTE-U data rate and the QoS requirements of WiFi networks. Using the energy function of 2D-HNNs, precise investigation of its minimization property can directly provide the solution of the optimization problem. Furthermore, the problem of allocating the unlicensed resources to LTE-U users is modeled as a 2D-HNN and its energy function is leveraged to allocate resources to LTE-U users based on their channel states. Numerical results show that the proposed algorithm allows the LTE-U BS to work efficiently in the unlicensed spectrum while protecting the WiFi networks. Moreover, more than 90% fairness among the LTE-U users is achieved when allocating the unlicensed resources to LTE-U users based on the proposed algorithm.

Specific emitter identification for satellite communication using probabilistic neural networks

SummaryElectromagnetic signal emitted by satellite communication (satcom) transmitters are used to identify specific individual uplink satcom terminals sharing the common transponder in real environment, which is known as specific emitter identification (SEI) that allows for early indications and warning (I&W) of the targets carrying satcom furnishment and furthermore the real time electromagnetic situation awareness in military operations. In this paper, the authors are the first to propose the identification of specific transmitters of satcom by using probabilistic neural networks (PNN) to reach the goal of target recognition. We have been devoted to the examination by exploring the feasibility of utilizing the Hilbert transform to signal preprocessing, applying the discrete wavelet transform to feature extraction, and employing the PNN to perform the classification of stationary signals. There are a total of 1000 sampling time series with binary phase shift keying (BPSK) modulation originated by five types of satcom transmitters in the test. The established PNNs classifier implements the data testing and finally yields satisfactory accuracy at 8 dB(±1 dB) carrier to noise ratio, which indicates the feasibility of our method, and even the keen insight of its application in military.

A Novel Configuration of A Microstrip Power Amplifier based on GaAs-FET for ISM Applications

Power Amplifiers (PA) are very indispensable components in the design of numerous types of communication transmitters employed in microwave technology. The methodology is exemplified through the design of a 2.45GHz microwave power Amplifier (PA) for the industrial, scientific and medical (ISM) applications using microstrip technology. The main design target is to get a maximum power gain while simultaneously achieving a maximum output power through presenting the optimum impedance which is characteristically carried out per adding a matching circuit between the source and the input of the power amplifier and between the load and the output of the power amplifier. A "T" matching technique is used at the input and the output sides of transistor for assure in band desired that this circuit without reflections and to obtain a maximum power gain. The proposed power amplifier for microwave ISM applications is designed, simulated and optimized by employing Advanced Design System (ADS) software by Agilent. The PA shows good performances in terms of return loss, output power, power gain and stability; the circuit has an input return loss of -38dB and an output return loss of -33.5dB. The 1-dB compression point is 8.69dBm and power gain of the PA is 19.4dBm. The Rollet's Stability measure B1 and the stability factor K of the amplifier is greater than 0 and 1 respectively, which shows that the circuit is unconditionally stable. The total chip size of the PA is 73.5× 36 mm2.

Towards development of portable instantaneous smart optical device for hemoglobin detection non invasively

Nowadays, large number of anaemia cases can be seen especially in women and children. It is caused due to low haemoglobin level in blood. Mostly conventional methods are used to calculate haemoglobin level. These methods involve pricking of human body with needle and sending blood sample to laboratory for further analysis which results in delay and chances of infection increases. This research work is aimed at designing a instantaneous non invasive small, portable and low cost device to determine hemoglobin value in blood which makes it completely mobile. The prototype is based on transmittance type PPG sensor having LEDs and photo detector. The developed prototype capability for hemoglobin detection is validated on 8 subjects by comparing its results with laboratory type digital calorimeter. As a result, the response of prototype has been proved with mean absolute error of 0.7 having a small bias of 0.1 g/deci litre (g/dl) with all data points lie within 95% limits. This shows good agreement and perfect correlation between developed prototype and standard instrument.

Research on a new type of electromagnetic transmitter based on PWM technology

An electromagnetic transmitter transmits electromagnetic waves with variable frequencies to the ground to obtain underground structure information and the distribution of mineral resources. In order to improve the power factor and reduce the volume and weight of the transmitter, a novel transmitter topology with pulse width modulation (PWM) rectifier is designed. Similar with the flux-oriented control in the motor speed regulation system, this paper provides flux-oriented control for a permanent magnet synchronous generator PWM rectifier. The mathematical model of the generator rectifier is established under the rotating coordinate system. Then, a novel decoupling control strategy without the exact value of the generator stator inductance is proposed to regulate the active current and the reactive current, and an outer voltage linear control strategy with the control amount of the square of the voltage is proposed to regulate the output voltage. Simulation and experimental results demonstrate the effectiveness of the system.

Research and development of continous wave 100 kW absorption harmonicfilter in X-band

A gradient leaky-wall waveguide loaded absorbing load filter structure is proposed, which is designed for harmonic suppression in super-high power transmitter of deep-space probe. The attenuation loss characteristics of the filter is analyzed according to the equivalent circuit method, and the massive structure is simulated by the electromagnetic field simulation software. The filter sample which includes one main waveguide, 288 deputy waveguides and 288 absorb loads is processed following the simulating and designing sizes. In order to prevent microwave from leaking and keep good air tightness under the condition of high power, all the components of the filter will be welded together by means of vacuum welding, and then the sample is cleaned ultrasonically. Finally, the filter sample is tested under small signal and large signal separately. According to our test results, the pass band max insertion loss of the filter is 0.3 dB, the min suppression of second harmonic is 75 dB, the min suppression of third harmonic is 50 dB, and the min suppression of fourth harmonic is 35 dB. The measured results show that they are almost the same as the simulation results, and consistent completely with the anticipated. We further conduct the high power experiment on the filter under a large signal of 100 kW, showing that the continuous wave power capacity of the filter can reach up to 100 kW through the power resistance test with the liquid-cooled system. All the test data show that the study and development are very successful. At present, the filer has been applied to a type of ground high power transmitter, and its performances and indicators behave well.

The Breakthrough Listen Search for Intelligent Life: 1.1–1.9 GHz Observations of 692 Nearby Stars

We report on a search for engineered signals from a sample of 692 nearby stars using the Robert C. Byrd Green Bank Telescope, undertaken as part of the $Breakthrough~Listen~Initiative$ search for extraterrestrial intelligence. Observations were made over 1.1$-$1.9 GHz (L band), with three sets of five-minute observations of the 692 primary targets, interspersed with five-minute observations of secondary targets. By comparing the "ON" and "OFF" observations we are able to identify terrestrial interference and place limits on the presence of engineered signals from putative extraterrestrial civilizations inhabiting the environs of the target stars. During the analysis, eleven events passed our thresholding algorithm, but a detailed analysis of their properties indicates they are consistent with known examples of anthropogenic radio frequency interference. We conclude that, at the time of our observations, none of the observed systems host high-duty-cycle radio transmitters emitting between 1.1 and 1.9 GHz with an Equivalent Isotropic Radiated Power of $\sim10^{13}$ W, which is readily achievable by our own civilization. Our results suggest that fewer than $\sim$ 0.1$\%$ of the stellar systems within 50 pc possess the type of transmitters searched in this survey.

The Circuit Analysis and Performance Evaluation of an Hc Type Magnetic Coupling Contactless Power Transformer that is Compatible with Both Solenoid and Circular Type Transformers

SUMMARYThere are two types of the transformers in a contactless power transfer system: solenoid type (H‐shaped) and circular type transformers. These two types of transformers are not compatible because their magnetic field structures are different. An Hc type transformer that is compatible with both transformer types has been proposed. The Hc type receiver adds a central magnetic pole by dividing the winding coil of the H‐shaped receiver. The Hc type receiver can change the magnetic field structure by changing the connections of the divided windings and can receive power from both types of transmitters. In this study, we conducted a circuit analysis and evaluated the performance of the Hc type transformer.

Vision Based Measurement applied to Industrial Instrumentation

Machine Vision applied in the area of Instrumentation and Measurement is known as Vision Based Measurement. Its application in industry is steadily increasing principally due to the recent developments in computer hardware and computer vision algorithms. In this article we discuss the possibilities of combining industrial local sensors with a camera and a computer, thus obtaining a new type of transmitter based in Machine Vision. The possibility of transforming visual information into digital data, which can be readily available in an industrial network, opens a variety of new applications. As a case study, we propose and implement a Vision Based Measurement system capable of measuring and transmitting the value indicated by a pointer-scale indicator. To verify the applicability of the proposed transmitter the following results are presented: (i) the associated standard uncertainty is evaluated; (ii) the influence of the image size in the transmitter’s uncertainty is investigated; (iii) the proposed transmitter is compared with a regular electronic transmitter and, (iv) its processing time is evaluated. The results obtained in laboratory are promising and indicate that the use of the proposed Machine Vision system in industry is a real possibility.

Bottom-up gamma and stages of waking

Gamma activity has been proposed to promote the feed forward or “bottom-up” flow of information from lower to higher regions of the brain during perception. The pedunculopontine nucleus (PPN) modulates waking and REM sleep, and is part of the reticular activating system (RAS). The properties of PPN cells are unique in that all PPN neurons fire maximally at gamma band frequency regardless of electrophysiological or transmitter type, thus proposed as one origin of “bottom-up” gamma. This property is based on the presence of intrinsic membrane oscillations subserved by high threshold, voltage-dependent calcium channels. Moreover, some PPN cells are electrically coupled. Assuming that the population of PPN neurons has the capacity to fire at ∼40Hz coherently, then the population as a whole can be expected to generate a stable gamma band signal. But what if not all the neurons are firing at the peaks of the oscillations? That means that some cells may fire only at the peaks of every second oscillation. Therefore, the population as a whole can be expected to be firing at a net ∼20Hz. If some cells are firing at the peaks of every fourth oscillation, then the PPN as a whole would be firing at ∼10Hz. Firing at rates below 10Hz would imply that the system is seldom firing at the peaks of any oscillation, basically asleep, in slow wave sleep, thus the activation of the RAS is insufficient to promote waking. This hypothesis carries certain implications, one of which is that we awaken in stages as more and more cells are recruited to fire at the peaks of more and more oscillations. For this system, it would imply that, as we awaken, we step from ∼10Hz to ∼20Hz to ∼30Hz to ∼40Hz, that is, in stages and presumably at different levels of awareness. A similar process can be expected to take place as we fall asleep. Awakening can then be considered to be stepwise, not linear. That is, the implication is that the process of waking is a stepwise event, not a gradual increase, suggesting that the brain can spend time at each of these different stages of arousal.

Effect of Quality Factor on Determining the Optimal Position of a Transmitter in Wireless Power Transfer Using a Relay

In this letter, the optimal placement of a transmitter is investigated under a given arrangement of a relay and a receiver for nonradiative wireless power transfer. Specifically, a closed-form equation is derived for the optimal coupling coefficient between the transmitter and the relay using an equivalent circuit model. Based on this theoretical analysis, it is found that the quality factor of the transmitter has a great effect on determining its optimal placement. In particular, the transmission efficiency can be improved by locating the resonator with a smaller quality factor (e.g., transmitter or receiver) closer to the relay. In order to support the validity of the analysis, the resonators, including the relay, receiver, and three different types of transmitters, are experimentally designed and fabricated. It is shown that our analytical results are well matched with the measured ones in various settings.

Performance and retention of lightweight satellite radio tags applied to the ears of polar bears (Ursus maritimus)

BackgroundSatellite telemetry studies provide information that is critical to the conservation and management of species affected by ecological change. Here we report on the performance and retention of two types (SPOT-227 and SPOT-305A) of ear-mounted Argos-linked satellite transmitters (i.e., platform transmitter terminal, or PTT) deployed on free-ranging polar bears in Eastern Greenland, Baffin Bay, Kane Basin, the southern Beaufort Sea, and the Chukchi Sea during 2007–2013.ResultsTransmissions from 142 out of 145 PTTs deployed on polar bears were received for an average of 69.3 days. The average functional longevity, defined as the number of days they transmitted while still attached to polar bears, for SPOT-227 was 56.8 days and for SPOT-305A was 48.6 days. Thirty-four of the 142 (24%) PTTs showed signs of being detached before they stopped transmitting, indicating that tag loss was an important aspect of tag failure. Furthermore, 10 of 26 (38%) bears that were re-observed following application of a PTT had a split ear pinna, suggesting that some transmitters were detached by force. All six PTTs that were still on bears upon recapture had lost the antenna, which indicates that antenna breakage was a significant contributor to PTT failure. Finally, only nine of the 142 (6%) PTTs—three of which were still attached to bears—had a final voltage reading close to the value indicating battery exhaustion. This suggests that battery exhaustion was not a major factor in tag performance.ConclusionsThe average functional longevity of approximately 2 months for ear-mounted PTTs (this study) is poor compared to PTT collars fitted to adult female polar bears, which can last for several years. Early failure of the ear-mounted PTTs appeared to be caused primarily by detachment from the ear or antenna breakage. We suggest that much smaller and lighter ear-mounted transmitters are necessary to reduce the risk of tissue irritation, tissue damage, and tag detachment, and with a more robust antenna design. Our results are applicable to other tag types (e.g., iridium and VHF systems) and to research on other large mammals that cannot wear radio collars.

Accounting for false mortality in telemetry tag applications

Deaths of animals in the wild are rarely observed directly, which often limits understanding of survival rates. Telemetry transmitters offer field ecologists the opportunity to observe mortality events in cases as the absence of animal movement. When observations of mortality are based on factors such as the absence of animal movement, live individuals can be mistaken for dead, resulting in biased estimates of survival. Additionally, tag failure or emigration might also influence estimates of survival in telemetry studies. Failing to account for mis-classification, tag failure, and emigration rates can result in overestimates of mortality rates by up two-fold, even when the data are corrected for obviously mistaken entries. We use a multi-state capture–recapture model with a misclassification parameter in estimating both the rate of permanent emigration and/or tag failure and the rate at which individuals are mistakenly identified as dead. We use this method on an annual telemetry survey of three species of native fish in the Murray river, Australia: Murray cod (Maccullochella peelii), trout cod (Maccullochella macquariensis) and golden perch (Macquaria ambigua). Evidence for higher mortality rates in the first year post-implantation occurred for Murray cod and golden perch, which is likely an effect of tagging and/or the transmitter, or transmitters shedding. Using simulations, we confirm that our model approach is robust to a broad range of misclassification and transmitter failure rates. With these simulations we also demonstrate that misclassification models that do not account for emigration will likely be erroneous if live and dead animals have different probabilities of detection. These findings will have a broad interest to ecologists wishing to account for multiple sources of misclassification error in capture-mark-recapture studies, with the caveat that the specifics of the approach are dependent on species, transmitter types and other aspects of experimental design which may or may not be amenable to the misclassification framework.

In situ measurement of salinity during seaward migration of Atlantic salmon post-smolts using acoustic transmitters with data-storage capabilities and conventional acoustic transmitters

BackgroundDevelopment of miniature acoustic transmitters and data-storage tags has provided new insights into ecology of free-ranging aquatic animals. In this study, we used a data-storage-type and a conventional acoustic transmitter, both equipped with a salinity sensor, to measure the in situ salinity experienced by Atlantic salmon post-smolts during the first phase of their marine migration in a Norwegian fjord. The data-storage transmitter conveyed stored salinity data accumulated over a period of up to 27 h prior to moving within the range of a receiver, while the conventional transmitter conveyed only real-time salinity data. Five post-smolts tagged with a conventional transmitter were manually tracked from a boat, and 15 post-smolts tagged with the data-storage transmitter were monitored by six transects consisting of 29 stationary receivers deployed from the river and throughout the fjord.ResultsAll tagged post-smolts primarily showed rapid seaward movements. They occasionally stayed in water with salinity below 20.0 psu in the inner part of the fjord, most likely because they were swimming close to the surface, where the salinity was low due to freshwater supply from the river. In the outer fjord, where full-salinity sea water (26.0–32.0 psu) was recorded in the entire water column, half (3 of 6) of the recorded fish still experienced low salinities (<20.0 psu) for periods between 2.25 and 54 h.ConclusionBoth types of salinity transmitters provided data on ambient salinity of the post-smolts during the seaward movement. In the outer fjord, the post-smolts likely visited one or several river mouths. It is not known whether this behaviour is normal for Atlantic salmon post-smolts during migration, but it might be advantageous in terms of reducing infestation risk from salmon lice, which have low survival in low salinities. The data-storage transmitters provided data on the ambient salinity history of the tagged fish, even when the fish were outside the detection range of receivers. By using this type of transmitters, we were able to collect salinity data during a four times longer period than with conventional transmitters.

Bottom-up gamma: the pedunculopontine nucleus and reticular activating system

Gamma rhythms have been proposed to promote the feed forward or "bottom-up" flow of information from lower to higher regions in the brain during perception. On the other hand, beta rhythms have been proposed to represent feed back or "top-down" influence from higher regions to lower. The pedunculopontine nucleus (PPN) has been implicated in sleep-wake control and arousal, and is part of the reticular activating system (RAS). This review describes the properties of the cells in this nucleus. These properties are unique, and perhaps it is the particular characteristics of these cells that allow the PPN to be involved in a host of functions and disorders. The fact that all PPN neurons fire maximally at gamma band frequency regardless of electrophysiological or transmitter type, make this an unusual cell group. In other regions, for example in the cortex, cells with such a property represent only a sub-population. More importantly, the fact that this cell group's functions are related to the capacity to generate coherent activity at a preferred natural frequency, gamma band, speaks volumes about how the PPN functions. We propose that "bottom-up" gamma band influence arises in the RAS and contributes to the build-up of the background of activity necessary for preconscious awareness and gamma activity at cortical levels.

Synaptic signalling and its interface with neuropathologies: snapshots from the past, present and future.

This 'Past to Future' Review as part of the 60th anniversary year of the Journal of Neurochemistry focuses on synaptic transmission and associated signalling, and seeks to identify seminal progress in neurochemistry over the last 10years which has advanced our understanding of neuronal communication in brain. The approach adopted analyses neurotransmitters on a case by case basis (i.e. amino acids, monoamines, acetylcholine, neuropeptides, ATP/purines and gasotransmitters) to highlight novel findings that have changed the way we view each type of transmitter, to explore commonalities and interactions, and to note how new insights have changed the way we view the biology of degenerative, psychiatric and behavioural conditions. Across all transmitter systems there was remarkable growth in the identification of targets likely to provide therapeutic benefit and which undoubtedly was driven by the elucidation of circuit function and new vistas of synaptic signalling. There has been an increasing trend to relate signalling to disease, notably for Alzheimer's and Parkinson's disease and related conditions, and which has occurred for each transmitter family. Forebrain circuitry and tonic excitatory control have been the centre of great attention yielding novel findings that will impact upon cognitive, emotional and addictive behaviours. Other impressive insights focus on gasotransmitters integrating activity as volume transmitters. Exciting developments in how serotonin, cholinergic, l-glutamate, galanin and adenosine receptors and their associated signalling can be beneficially targeted should underpin the development of new therapies. Clearly integrated, multifaceted neurochemistry has changed the way we view synaptic signalling and its relevance to pathobiology. Highlighted are important advances in synaptic signalling over the last decade in the Journal of Neurochemistry. Across all transmitter systems elucidation of circuit function, and notably molecular insights, have underpinned remarkable growth in the identification of targets likely to provide therapeutic benefit in neuropathologies. Another commonality was wide interest in forebrain circuitry and its tonic excitatory control. Increasingly observations relate to signalling in disease and behavioural conditions. This article is part of the 60th Anniversary special issue.

Do transmitters affect survival and body condition of American beavers Castor canadensis?

One key assumption often inferred with using radio‐equipped individuals is that the transmitter has no effect on the metric of interest. To evaluate this assumption, we used a known fate model to assess the effect of transmitter type (i.e. tail‐mounted or peritoneal implant) on short‐term (one year) survival and a joint live—dead recovery model and results from a mark—recapture study to compare long‐term (eight years) survival and body condition of ear‐tagged only American beavers Castor canadensis to those equipped with radio transmitters in Voyageurs National Park, Minnesota, USA. Short‐term (1‐year) survival was not influenced by transmitter type (wi = 0.64). Over the 8‐year study period, annual survival was similar between transmitter‐equipped beavers (tail‐mounted and implant transmitters combined; 0.76; 95% CI = 0.45–0.91) versus ear‐tagged only (0.78; 95% CI = 0.45–0.93). Additionally, we found no difference in weight gain (t9 = 0.25, p = 0.80) or tail area (t11 = 1.25, p = 0.24) from spring to summer between the two groups. In contrast, winter weight loss (t22 = ‐ 2.03, p = 0.05) and tail area decrease (t30 = ‐ 3.04, p = 0.01) was greater for transmitterequipped (weight = ‐ 3.09 kg, SE = 0.55; tail area = ‐ 33.71 cm2, SE = 4.80) than ear‐tagged only (weight = ‐ 1.80 kg, SE = 0.33; tail area = ‐ 12.38 cm2, SE = 5.13) beavers. Our results generally support the continued use of transmitters on beavers for estimating demographic parameters, although we recommend additional assessments of transmitter effects under different environmental conditions.

Current turn-off in an ungrounded horizontal loop: experiment and theory

An ungrounded horizontal loop, a common transmitter type in TEM surveys, makes up a system with distributed parameters with the earth under it. It can be simulated by an equivalent circuit with lumped parameters at late times and/or low frequencies, but at early times commensurate with the period of free current oscillations, the lumped circuit model fails to account for experimental data. At high frequencies and/or early times, the wire, in combination with the underlying earth, forms a transmission line in which current behaves according to the wave equation. This model allows calculating the current at any time and at any loop point with reference to the theory of long transmission lines. At early times, the loop self-responses depend on near-surface resistivity and environment and its primary magnetic field differs from that predicted by the classical theory of TEM surveys. Therefore, inversion of early-time rerponse in terms of the conventional TEM system model is meaningless. However, as illustrated with a loop shunted by a matching resistor, the loop model as a combination of two transmission lines enables the inversion of the early-time current response in terms of the line parameters and near-surface resistivity.

円形及びソレノイド型磁界結合方式非接触給電トランスと共用可能なHc型トランスの回路解析と性能評価

There are two types of the transformers in a contactless power transfer system: solenoid type (H-shaped) and circular type transformers. These two types of transformers are not compatible because their magnetic field structures are different. An Hc type transformer that is compatible with both transformer types has been proposed. The Hc type receiver adds a central magnetic pole by dividing the winding coil of the H-shaped receiver. The Hc type receiver can change the magnetic field structure by changing the connections of the divided windings and can receive power from both types of transmitters. In this study, we conducted a circuit analysis and evaluated the performance of the Hc type transformer.

Laser-guided Neuronal Tracing In Brain Explants.

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake through electroporation in brain explants with targeted laser illumination and matching filter goggles during the procedure. The described technique of in vitro electroporation by itself yields relatively good visual control for targetting certain areas of the brain. By combining it with laser excitation of fluorescent genetic markers and their read-out through band-passing filter goggles, which can pick up the emissions of the genetically labeled cells/nuclei and the fluorescent tracing dye, a researcher can substantially increase the accuracy of injections by finding the area of interest and controlling for the dye-spread/uptake in the injection area much more efficiently. In addition, the laser illumination technique allows to study the functionality of a given neurocircuit by providing information about the type of neurons projecting to a certain area in cases where the GFP expression is linked to the type of transmitter expressed by a subpopulation of neurons.