scholarly journals Hardware Design of a High Dynamic Range Radio Frequency (RF) Harmonic Measurement System

Instruments ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 16 ◽  
Author(s):  
Ram Narayanan ◽  
Kyle Gallagher ◽  
Gregory Mazzaro ◽  
Anthony Martone ◽  
Kelly Sherbondy

Radio frequency (RF) circuit elements that are traditionally considered to be linear frequently exhibit nonlinear properties that affect the intended operation of many other RF systems. Devices such as RF connectors, antennas, attenuators, resistors, and dissimilar metal junctions generate nonlinear distortion that degrades primary RF system performance. The communications industry is greatly affected by these unintended and unexpected nonlinear distortions. The high transmit power and tight channel spacing of the communication channel makes communications very susceptible to nonlinear distortion. To minimize nonlinear distortion in RF systems, specialized circuits are required to measure the low level nonlinear distortions created from traditionally linear devices, i.e., connectors, cables, antennas, etc. Measuring the low-level nonlinear distortion is a difficult problem. The measurement system requires the use of high power probe signals and the capability to measure very weak nonlinear distortions. Measuring the weak nonlinear distortion becomes increasingly difficult in the presence of higher power probe signals, as the high power probe signal generates distortion products in the measurement system. This paper describes a circuit design architecture that achieves 175 dB of dynamic range which can be used to measure low level harmonic distortion from various passive RF circuit elements.

Author(s):  
О. V. Shefer

As part of the article the scientifically grounded synthesis of the algorithm of adaptive compensation of nonlinear distortion (ACNLD) of radio devices based on the use of the mathematical apparatus of a theory of nonlinear analysis (Voltaire series). Actual speed and accuracy of adaptation were determined by choosing the optimal value of transmission coefficient. Some actual causes of limitation of dynamic range and appearance of internal noises of radio equipment were established. The estimation of ACNLD noise influence on its efficiency was carried out, and also the influence of signal component of the reference input ACNLD on radio quality indicators


2018 ◽  
Vol 1067 ◽  
pp. 072032 ◽  
Author(s):  
Z. K. Liu ◽  
F. Y. Chang ◽  
L. H. Chang ◽  
M. H. Chang ◽  
S. W. Chang ◽  
...  

Author(s):  
Caio Dias Fernandes ◽  
Bruna Hartmann Coutinho ◽  
Bruno Hashinokuti Iwamoto ◽  
breno borges ◽  
Dimitri Zuave Costa da Silva ◽  
...  

Author(s):  
Vladimir Anfinogentov ◽  
Kamil Karimov ◽  
Artem Kuznetsov ◽  
Ilnur Nureev ◽  
Airat Sakhabutdinov ◽  
...  

Abstract: Nonlinear spectrum distortions are caused by the peculiarities of the operation of charge-coupled device elements (CCD), in which the signal exposition time (TINT) is one of the significant parameters. A change of TINT on a CCD leads to a nonlinear distortion of the resulting spectrum. Nonlinear distortion of the spectrum, in its turn, leads to errors in determining the central wavelength of Fiber Bragg Gratings (FBG) and spectrally sensitive sensors, which, in general, negatively affects the accuracy of measuring systems. The paper proposes an algorithm for correcting nonlinear distortions of the spectrum obtained on a spectrum analyzer using CCD as a receiver. It is shown that preliminary calibration of the optical spectrum analyzer with subsequent mathematical processing of the signal makes it possible to make corrections in the resulting spectrum, thereby leveling the errors caused by measurements at different TINT.


Author(s):  
Antonio Ramos ◽  
Abelardo Ruiz ◽  
Enrique Riera

Ultrasonic imaging & NDE applications can greatly improve their signal-to-noise ratios (SNR) by driving each transducer (composing piezoelectric arrays) with a spike giving pulsed power of k-Watts, repetitively at a PRF = 5000 spikes/s, by using a HV capacitive-discharge generator. However very-high levels, of pulsed intensities (3-10 A) and voltages (300-700 V) must be considered for a rigorous spike modeling. Even though the consumed "average" power will be small, the intensity through each transducer achieves several amperes, so the pulsed powers delivered by each HV generator can attain levels higher than in CW high-power ultrasonic applications: e.g., up to 5 kW / spike. This is concluded here from a transient modeling of the loaded generator. Then, unforeseen phenomena rise: intense brief pulses of driving power & emitted force in transducers, and non-linearities in driver semiconductors, because their characteristic curves only include linear ranges. But fortunately, piezoelectric devices working in this intense regime do not show serious heating problems, because the average power remains being moderate. Intensity, power and voltage, driving a broadband transducer from a HV capacitive pulser, are calculated to drastically improve (in ≅ 40 dB) the ultrasonic net dynamic range available, with emitted forces ≅ 250 Newtons pp and E/R received pulses of 70 V pp.


2019 ◽  
Vol 39 (6) ◽  
pp. 0612003
Author(s):  
马冬晓 Dongxiao Ma ◽  
汪家春 Jiachun Wang ◽  
陈宗胜 Zongsheng Chen ◽  
王冰 Bing Wang ◽  
刘洋 Yang Liu

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