MODELING OF STABLE CURRENT GENERATORS FOR MICROWAVE AMPLIFIERS

2020 ◽  
Author(s):  
Ю.А. НИКИТИН ◽  
А.Д. СЕДИНИН ◽  
В.А. ЮРОВА
Keyword(s):  
Dynamic Range ◽  
Comparative Modeling ◽  
Radio Communication ◽  
Current Mirrors ◽  
Microwave Amplifiers ◽  
Computer Package ◽  
Stable Current

В устройствах радиосвязи и электроники усилители во многом определяют динамический диапазон и чувствительность аппаратуры. Возможно построение усилительных структур на управляемых токовых зеркалах. В работе рассмотрены варианты построения квазилинейных усилительных структур на токовых зеркалах. С помощью пакета MicroCap 11 проведено их моделирование и сравнение. In radio communication and electronics devices, amplifiers largely determine the dynamic range and sensitivity of the equipment. It is possible to build amplifying structures using controlled current mirrors (CM). The paper considers variants of construction of broadband quasi-linear amplifying structures on CM. Their comparative modeling was carried out with the help of the computer package Micro Cap 11.

Low Temperature a-Si:H Pixel Circuits for Mechanically Flexible AMOLED Displays

2003 ◽  
Vol 769 ◽  
Author(s):  
Arokia Nathan ◽  
Denis Striakhilev ◽  
Peyman Servati ◽  
Kapil Sakariya ◽  
Anil Kumar ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Light Emitting Diode ◽  
Thin Film Transistor ◽  
Light Emitting ◽  
Plastic Substrates ◽  
Organic Light Emitting Diode ◽  
Current Mirrors ◽  
Organic Light ◽  
Driver Circuit ◽  
Circuit Integration

AbstractThis paper presents the first demonstration of amorphous silicon (a-Si:H) thin film transistor (TFT) circuit integration on plastic substrates. The circuits compensate for material shortcomings such as metastable threshold voltage (VT) shift and high contact resistance, to supply stable and predictable currents to drive organic light emitting diode (OLED) displays on plastic. Various drive circuits were fabricated and tested. The simplest pixel driver circuit possible is the two TFT voltage-programmed circuit, which is very susceptible to any shift in VT of the drive TFT. To overcome this problem, we have developed current-programmed pixel circuits based on the current mirror circuit family, which include the simple and cascode current mirrors. The OLED current in these circuits is virtually independent of any VT shift or mobility variation in the drive TFT. Results show that the circuits provide higher linearity and dynamic range than currently available pixel circuits while minimizing the pixel area.

scholarly journals Enzymatic Low Volume Passive Sweat Based Assays for Multi-Biomarker Detection

Biosensors ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 13 ◽  
Author(s):  
Ashlesha Bhide ◽  
Sarah Cheeran ◽  
Sriram Muthukumar ◽  
Shalini Prasad
Keyword(s):  
Dynamic Range ◽  
Low Cost ◽  
Simultaneous Detection ◽  
Porous Membrane ◽  
Zno Films ◽  
Current Response ◽  
Biomarker Detection ◽  
High Concentration ◽  
Sensor Performance ◽  
Stable Current

Simultaneous detection of correlated multi-biomarkers on a single low-cost platform in ultra-low fluid volumes with robustness is in growing demand for the development of wearable diagnostics. A non-faradaic biosensor for the simultaneous detection of alcohol, glucose, and lactate utilizing low volumes (1–5 μL) of sweat is demonstrated. Biosensing is implemented using nanotextured ZnO films integrated on a flexible porous membrane to achieve enhanced sensor performance. The ZnO sensing region is functionalized with enzymes specific for the detection of alcohol, glucose, and lactate in the ranges encompassing their physiologically relevant levels. A non-faradaic chronoamperometry technique is used to measure the current changes associated with interactions of the target biomarkers with their specific enzyme. The specificity performance of the biosensing platform was established in the presence of cortisol as the non-specific molecule. Biosensing performance of the platform in a continuous mode performed over a 1.5-h duration showed a stable current response to cumulative lifestyle biomarker concentrations with capability to distinguish reliably between low, mid, and high concentration ranges of alcohol (0.1, 25, 100 mg/dL), glucose (0.1, 10, 50 mg/dL), and lactate (1, 50, 100 mM). The low detection limits and a broader dynamic range for the lifestyle biomarker detection are quantified in this research demonstrating its suitability for translation into a wearable device.

scholarly journals Аdaptive broadband low-noise RF amplifier

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 66-74
Author(s):  
I. Yu. Malevich ◽  
P. V. Zayats
Keyword(s):  
Dynamic Range ◽  
Noise Figure ◽  
Low Noise ◽  
Technical Solution ◽  
Radio Communication ◽  
Switched Networks ◽  
Rf Amplifier ◽  
The Creation ◽  
Transformer Feedback ◽  
Overload Capacity

Adaptive broadband low-noise radio frequency amplifiers (ABLNRFA) are widely used in the construction of systems for protecting radio receiving paths from nonlinear damage in a non-stationary electromagnetic environment (EME). One of the promising focus areas on the creation of ABLNRFA is the development of devices in the class of circuits with switched networks. The creation of such devices has certain features, since, along with the need to ensure a low noise figure and digital control of the regulation characteristic, it is required to provide high linearity and a large dynamic range (DR) of the device. This paper presents the results of the logical-heuristic synthesis of ABLNRFA with an adaptively adjustable transducer gain, which changes due to switching of transformer feedback circuits. In order to check the functional and technical characteristics of the synthesized ABLNRFA and optimize its parameters, a model was developed and studied in the ADS environment. The proposed ABLNRFA technical solution provides a discrete (23, 14, 10 and 5 dB) wideband change in the transmission coefficient, while the DR for third-order intermodulation in terms of a 1 MHz band is 83, 92, 98 and 104 dB, respectively. A step change in the transducer gain in the circuit of the lossless feedback circuit developed by ABLNRFA avoids the accumulation of additional noise in the structure and provides a low-noise figure that does not exceed 1 dB. The technical characteristics of ABLNRFA allow one to adaptively increase the overload capacity of the radio receiving path with a proportional expansion of its DR in the conditions of non-stationary EME, and thus increase the efficiency of the level protection system against nonlinear damage to the receiving paths of radio communication, radar and radio navigation.

scholarly journals Increasing the noise immunity of radio receiving paths with automatic sensitivity control

Doklady BGUIR ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 74-82
Author(s):  
Р. V. Zayats ◽  
I. Y. Malevich
Keyword(s):  
Transmission Coefficient ◽  
Noise Immunity ◽  
Dynamic Range ◽  
Response Speed ◽  
Significant Loss ◽  
Radio Communication ◽  
Electromagnetic Environment ◽  
Sampling Step ◽  
Radio Navigation ◽  
Sensitivity Control

 The relevance of the study of automatic sensitivity control systems (ASC) is determined by their demand for the creation and modernization of radio receiving paths (RRP) with increased noise immunity for radar systems, radio navigation and radio communication. The article analyzes typical attenuating ASCs, which are traditionally widely used to match the dynamic range (DR) of the RRP with the DR of a group radio signal, determined by the current state of the electromagnetic environment at the receiving system location. The fundamental possibility of increasing the noise immunity of RRPs with attenuating ASCs is shown on the basis of the current analysis of the resulting output signal in the IF main filter band. At the same time, it was found that the procedure for determining the optimal value of the attenuator transmission coefficient is characterized by low response speed. In addition, an increase in noise immunity in a RRP with such ASC leads to a significant loss of sensitivity. To overcome the disadvantages of attenuating ASCs, structures that implement the exchange of the transmission coefficient of the RRP to DR and linearity are proposed. Studies of various possible ASC structures have shown that with a proportional exchange of the transmission coefficient for the DR, an improvement in the noise immunity of the RRP is provided while maintaining a high sensitivity of the system. An original ASC system is proposed, which is invariant to the sampling step of the transmission coefficients of controlled elements with increased performance. The considered structural solutions and algorithms make it possible to optimize the technical appearance of RRPs for radar, radio navigation and radio communication with increased noise immunity and to adapt their characteristics to the conditions of nonstationary electromagnetic environment. 

A Stable Field Emission Electron Source

1977 ◽  
Vol 35 ◽  
pp. 58-59
Author(s):  
W.R. Bottoms ◽  
G.B. Haydon
Keyword(s):  
Field Emission ◽  
Signal To Noise Ratio ◽  
High Brightness ◽  
Electron Sources ◽  
Brightness Field ◽  
Current Densities ◽  
Properties Of Materials ◽  
Stable Field ◽  
Stable Current ◽  
Careful Design

There is great interest in improving the brightness of electron sources and therefore the ability of electron optical instrumentation to probe the properties of materials. Extensive work by Dr. Crew and others has provided extremely high brightness sources for certain kinds of analytical problems but which pose serious difficulties in other problems. These sources cannot survive in conventional system vacuums. If one wishes to gather information from the other signal channels activated by electron beam bombardment it is necessary to provide sufficient current to allow an acceptable signal-to-noise ratio. It is possible through careful design to provide a high brightness field emission source which has the capability of providing high currents as well as high current densities to a specimen. In this paper we describe an electrode to provide long-lived stable current in field emission sources.The source geometry was based upon the results of extensive computer modeling. The design attempted to maximize the total current available at a specimen.

Slow-Scan CCD Observation of Backscattering Patterns in SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1308-1309
Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Lens System ◽  
Wide Dynamic Range ◽  
Peltier Cooler ◽  
Diffraction Patterns ◽  
Scanning Electron

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).

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