scholarly journals Design of a reconfigurable front-end for a multistandard receiver for the frequency range of 800 MHz to 2.5 GHz

2018 ◽  
Vol 46 (6) ◽  
pp. 1144-1165 ◽  
Author(s):  
G. Zare Fatin ◽  
Z.D. Koozehkanani ◽  
Ali Fotowat-Ahmady ◽  
Jafar Sobhi ◽  
Ronan Farrell
Keyword(s):  
Frequency Range ◽  
Front End ◽  
Multistandard Receiver

scholarly journals Operational Amplifiers Revisited for Low Field Magnetic Resonance Relaxation Time Measurement Electronics

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 1
Author(s):  
Najlaa K. Almazrouei ◽  
Michael I. Newton ◽  
Robert H. Morris
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
Field Measurements ◽  
Time Measurement ◽  
Operational Amplifiers ◽  
Frequency Range ◽  
Sensor Applications ◽  
Low Field ◽  
Front End ◽  
Resonance Relaxation

Advances in permanent magnet technology has seen more reports of sensor applications of low field magnetic resonance. Whilst most are either in the 10–20 MHz range or in the earth’s field, measurements at below 1 MHz are beginning to become more widespread. This range is below the need for careful radio frequency electronics design but above the audio domain and represents an interesting cross over. Many commercial spectrometers do not include the pulse power amplifier, duplexer and preamplifier as these depend on the frequency range used. In this work we demonstrate that, with the current specifications of the humble operational amplifier, the most simple form of an inverting design using only two resistors and decoupling, can effectively provide this ‘front end’ electronics. The low powers used mean crossed Ge diodes provide an excellent duplexer and it is suitable for battery powered applications.

scholarly journals Runaway electron diagnostics for the COMPASS tokamak using EC emission

2019 ◽  
Vol 203 ◽  
pp. 03006
Author(s):  
Michal Farnik ◽  
Jakub Urban ◽  
Jaromir Zajac ◽  
Ondrej Bogar ◽  
Ondrej Ficker ◽  
...  
Keyword(s):  
Runaway Electron ◽  
Horn Antenna ◽  
Runaway Electrons ◽  
Electron Cyclotron Emission ◽  
Frequency Range ◽  
Front End ◽  
Suprathermal Electrons ◽  
Cyclotron Emission ◽  
Heterodyne Radiometer ◽  
Generation Mechanisms

An electron cyclotron emission (ECE) diagnostic of suprathermal electrons was utilised for runaway electron (RE) experiments purposes in the COMPASS tokamak. Our vertical ECE (V-ECE) system consists of a 16-channel heterodyne radiometer and an E-band horn antenna with a 76.5-88 GHz frequency range front-end. Simulations used for the design of the diagnostic showed a possibility of detecting the emission of low-energy (50-140 keV) runaway electrons. We realized measurements with both extraordinary (X-) and ordinary (O-) mode linear polarizations. The amplitudes of the X-mode and O-mode signals are similar, which can be explained by depolarised reflected radiation. V-ECE measurements in low-density flattop discharges and in discharges with massive gas injections of high-Z elements show correlations with other RE diagnostics. Our results are in the agreement with the principles of the primary runaway generation mechanisms.

Design of Local Oscillator Based on DDS of High Performance Short-Wave Receiver

2013 ◽  
Vol 834-836 ◽  
pp. 1140-1144 ◽  
Author(s):  
Yong Tai Chen ◽  
Chang Jing Sun ◽  
Bin Zang ◽  
Long Cheng ◽  
Jing Tang ◽  
...  
Keyword(s):  
High Performance ◽  
Gain Control ◽  
Local Oscillator ◽  
Short Wave ◽  
Frequency Multiplier ◽  
Test Results ◽  
Frequency Range ◽  
Front End ◽  
Tracking Filter ◽  
Spurious Signals

Phase noise and spurious signals of local oscillator will affect the performance of short-wave receiver. The structure of receiver's front-end part based on DDS is introduced to realize a high-performance local oscillator of short-wave receiver. Then measures were taken to improve the LO's performance, including using external directly frequency multiplier as DDS' clock to improve the purity of frequency spectrum, tracking filter to degrade harmonics and gain control circuit to remain constant amplitude in the desired frequency range. At last, test results show that the above-mentioned measures improve the receiver's performance.

Surface Micromachined Dielectrophoretic Gates for the Front-End Device of a Biodetection System

2005 ◽  
Vol 128 (1) ◽  
pp. 14-19 ◽  
Author(s):  
Conrad D. James ◽  
Murat Okandan ◽  
Paul Galambos ◽  
Seethambal S. Mani ◽  
Dawn Bennett ◽  
...  
Keyword(s):  
Phase Separation ◽  
Radio Frequency ◽  
Fluorescent Labeling ◽  
Frequency Range ◽  
Flowing Fluid ◽  
Separation Device ◽  
Air Samples ◽  
Biological Particles ◽  
Front End ◽  
Biological Analytes

We present a novel separation device for the front-end of a biodetection system to discriminate between biological and non-biological analytes captured in air samples. By combining AC dielectrophoresis along the flow streamlines and a field-induced phase-separation, the device utilizes “dielectrophoretic gating”to separate analytes suspended in a flowing fluid based on their intrinsic polarizability properties. The gates are integrated into batch fabricated self-sealed surface-micromachined fluid channels. We demonstrate that setting the gate to a moderate voltage in the radio frequency range removed bacteria cells from a mixture containing non-biological particles without the need for fluorescent labeling or antibody-antigen hybridization, and also validate experimentally basic relations for estimating the gate performance.

scholarly journals Design of Tunable Monopole Arm Planar Spiral Antenna for Cognitive Radio

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Rahul Yadav
Keyword(s):  
Cognitive Radio ◽  
Frequency Tuning ◽  
Impedance Matching ◽  
Ground Plane ◽  
Excitation Frequency ◽  
Antenna Design ◽  
Frequency Range ◽  
Spiral Antenna ◽  
Front End ◽  
Quarter Wavelength

This paper presents a spiral antenna design operating in the frequency range of 1–15 GHz having both selective notch bands and wideband response. The main feed arm of spiral antenna is configured as rectangular monopole of width quarter wavelength to achieve impedance matching with standard 50 Ω excitation. Frequency tuning in the design is achieved by placing varactor diode at an appropriate position along the spiral arms and in the ground plane. The design offers a peak gain of 3.4 dB (simulated) and 3 dB (measured). The unique frequency response of antenna makes its suitable to be used for front-end system of cognitive radio for sensing the spectrum in various modes.

Visualization of Acoustic Pressure Radiation From Complex Vibrating Structures

1999 ◽  
Author(s):  
Nassif Rayess ◽  
Sean F. Wu
Keyword(s):  
Acoustic Pressure ◽  
Complex Structure ◽  
Excitation Frequency ◽  
High Fidelity ◽  
State University ◽  
Passenger Vehicle ◽  
Frequency Range ◽  
Wayne State University ◽  
Front End ◽  
Helmholtz Equation Least Squares

Abstract This paper demonstrates visualization of the radiated acoustic pressures from a complex structure by using the Helmholtz Equation Least Squares (HELS) method (Wang and Wu, 1997; Wu and Wang, 1998; Wu and Yu, 1998). The structure under consideration has the same geometry and dimensions as those of a real, full-size passenger vehicle front end. Random noises generated by a high-fidelity loudspeaker installed inside the vehicle buck are measured at certain distances away from the vehicle surface. These measured signals are taken as the input to a computer model based on the HELS method. Experiments are conducted inside a 12’ by 12’ by 6.5’ walk-in size, fully anechoic chamber at the Acoustics, Vibration and Noise Control Laboratory of Wayne State University. The reconstructed acoustic pressures on the vehicle buck surface and in the field are compared with the measured data at the same locations. Also shown are comparisons of the reconstructed and measured acoustic pressure spectra at various locations on the vehicle buck surface. Results show that good agreements can be obtained with relatively few expansion functions in the low-to-mid frequency range. The accuracy of reconstruction, however, decreases with the increase of the excitation frequency and measurement distance as expected. Nevertheless, the HELS method is shown to be relatively insensitive to the complexities of a vibrating structure, which may make it potentially a viable noise diagnostic tool for engineers.

scholarly journals DEVELOPMENT AND INVESTIGATION OF INPUT AMPLIFIER FOR THE OSCILOSCOPE

2020 ◽  
Vol 12 (0) ◽  
pp. 1-5
Author(s):  
Andžej Borel
Keyword(s):  
Dynamic Range ◽  
Step Response ◽  
Signal Acquisition ◽  
Response Distortion ◽  
Frequency Range ◽  
Variable Gain ◽  
Input Amplifier ◽  
Front End ◽  
Vertical Scale ◽  
Sensitivity Range

Digital oscilloscope’s structure has analog signal acquisition circuit, which transforms signal’s amplitude to fit ADC dynamic range. This circuit is commonly called oscilloscope’s vertical or front-end amplifier. Difficulty in designing front-end amplifiers in GHz range largely affects higher frequency range oscilloscope’s price. This work is focused on designing a front-end amplifier using discrete and openly sold components. We propose a design for attenuator, buffer, variable gain circuits. Amplifier’s prototype is designed. Main characteristics of the amplifier were measured. Measured bandwidth is 3 GHz. Amplifier’s gain and attenuation can support vertical scale sensitivity range from 10 mV/div to 1 V/div. Step response distortion is under 10 %. SMD and PTH relay model attenuators were evaluated. In this paper we review oscilloscope’s front-end purpose and structure. We review amplifiers design and provide the results of experimental measurements.

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